Philae settles in dust-covered ice

Before going into hibernation in the early hours of 15 November 2014, the Philae lander was able to conduct experiments and return its data to Earth. In this blog post we look at the preliminary analysis conducted by the lander’s Multi-Purpose Sensors for Surface and Subsurface Science instrument package, MUPUS.

Focus on MUPUS. Credits: ESA/ATG medialab

Focus on MUPUS. Credits: ESA/ATG medialab

MUPUS began observing the environment around Comet 67P/Churyumov-Gerasimenko once Philae was released from the Rosetta orbiter at 08:35 GMT on 12 November (this is spacecraft time; the signal confirming separation arrived at Earth just over 28 minutes later, at 09:03 GMT).

The first touchdown recorded by Philae occurred at 15:34 GMT (with the signal arriving on Earth at 16:03 GMT), but it later transpired that the harpoons and ice screws did not deploy as planned and the lander subsequently rebounded, experiencing two further touchdowns, at 17:25 and 17:32 GMT (spacecraft time), respectively.

Because part of the MUPUS package was contained in the harpoons, some temperature and accelerometer data could not be gathered. However, the MUPUS thermal mapper, located on the body of the lander, worked throughout the descent and during all three touchdowns.

At Philae’s final landing spot, the MUPUS probe recorded a temperature of –153°C close to the floor of the lander’s balcony before it was deployed. Then, after deployment, the sensors near the tip cooled by about 10°C over a period of roughly half an hour.

“We think this is either due to radiative transfer of heat to the cold nearby wall seen in the CIVA images or because the probe had been pushed into a cold dust pile,” says Jörg Knollenberg, instrument scientist for MUPUS at DLR.

The probe then started to hammer itself into the subsurface, but was unable to make more than a few millimetres of progress even at the highest power level of the hammer motor.

“If we compare the data with laboratory measurements, we think that the probe encountered a hard surface with strength comparable to that of solid ice,” says Tilman Spohn, principal investigator for MUPUS.

Looking at the results of the thermal mapper and the probe together, the team have made the preliminary assessment that the upper layers of the comet’s surface consist of dust of 10–20 cm thickness, overlaying mechanically strong ice or ice and dust mixtures.

At greater depths, the ice likely becomes more porous, as the overall low density of the nucleus – determined by instruments on the Rosetta orbiter – suggests.

Looking to the future, Tilman Spohn says, “MUPUS could be used again if we get enough power. Then we could perform direct observations of the layer that the probe is standing in and see how it evolves as we get closer to the Sun.”

While the full analyses of the lander’s multiple touchdowns and the data collected during descent and landing are on-going, the Rosetta orbiter continues its science mission at Comet 67P/C-G. Over the next year it will follow the comet as it draws ever nearer to the Sun, watching how its surface and surrounding environment evolves.

The thermal probe of MUPUS was originally developed at the Institute of Planetology of the University of Münster together with the Space Research Centre in Warsaw and other international partners. It is maintained and operated by an international team led by the DLR Institute of Planetary Research in Berlin.



  • Paul Rybak says:

    A truly phenomenal achievement!

  • Jacob nielsen says:

    This info, I predict, will lead to this comment: " it is not ice, it is solid rock"

    • Ross says:

      Yeah hopefully some samples were obtained. I need to read the papers that will be published because I can't believe any honest scientist would conclude definitively with no prior bias that ice is the only possible material able to produce the data we observed.

      Why would a solid she'll of ice be on the outside of a loose conglomerate? Maybe if the sun's heat melted/sublimated the present layer to solid ice, but then we'd expect a softened relief without the evident craters, mesas, cliffs, and peaks.

      • Jacob nielsen says:

        Ther is a wery interesting process called sintering, which readily explains why a crust can form on top of a fluffy snow-cone even with no melting. I'm no expert though, but I've seen snow do that.

    • THOMAS says:

      @ Jacob nielsen

      Not so fast with your scoffing, Jacob. Read the presentation again. It is not “info”, it is mere SUPPOSITION made on the basis of what is EXPECTED and HOPED FOR by the standard theory. The title is way too affirmative, given the actual content of the presentation.

      Note in particular what Jörg Knollenberg actually said:
      “We THINK this is EITHER due to radiative transfer of heat to the COLD NEARBY WALL seen in the CIVA images OR because the probe had been pushed into a cold dust pile,” says Jörg Knollenberg, instrument scientist for MUPUS at DLR. (My capitals in the quote)

      Then note what Tilman Spohn, principal investigator for MUPUS, said:
      “If we compare the data with laboratory measurements, we THINK that the probe encountered a HARD surface with strength COMPARABLE TO that of solid ice,” says Tilman Spohn, principal investigator for MUPUS.

      And presumably comparable to the hardness and strength of various types of rock too, but he forgets to add that….

      Doesn’t sound like hard fact to me. But I guess people hear and understand what they want to hear and understand.

      Now look again at that close-up photo Philae sent back of that “cold nearby wall” Jörg Knollenberg refers to. Nobody will fortunately ever be able to claim that that is simply a “cold dust pile” and not solid rock (in which, BTW, I recently pointed out in this post: a number of embedded features which closely resemble spiral roofing nails but which can only be the result of electric discharge machining of the rock).

      Don’t forget, finally, that the hypothesized “solid ice” model poses nearly as much of a problem for interpreting the density data (allegedly “40% of the density of water” for the comet nucleus as a whole) as the solid rock model does. Who can seriously believe that a rock-solid outer crust of ice (or rock) suddenly gives way to something much less dense a few metres below the surface, all over the comet, including in the neck region? It beggars belief!

      Personally, I can’t wait for the findings of the CONSERT radar instrument to be released. Those will settle once and for all the debate about whether the comet is virtually hollow or not and whether it is made of solid rock or not.

      • Jacob nielsen says:

        @THOMAS, the expression on my face was a smile with a frown, and yes I had you in mind: this text per se is a perfect crack for driving wedges. But THOMAS, really, roofing nails? On a comet? They are rivets for sure and the big bright object is a fragment of a Spitfire wing.

        • THOMAS says:

          @ Jacob nielsen,

          I can understand the smile, but why the frown? (Personally, I laughed out loud when I read the article). Was it because the two tentative, unfounded suppositions made by the scientists were a complete let-down after the triumphant headline?

          No need to drive any wedges, a child could pull the internal logic of this article apart with the tips of its fingers. I'm surprised you didn't see the flaws in the "evidence" yourself.

          You apparently also had a problem reading my above post, but perhaps you have too literal a mind: I speak of "a number of embedded features WHICH CLOSELY RESEMBLE spiral roofing nails BUT WHICH CAN ONLY BE the result of electric discharge machining of the rock". It’s what we call a “comparison”, and one which is not only strikingly valid when you compare the feature I have observed with the sort of spiral nail commonly used by roofers, but which also pinpoints its MACHINING origin.

          Do I need to spell it out, Jacob: spiral roofing nails are machined by MEN, whereas the feature I have observed was necessarily machined by NATURAL FORCES. And the only natural force capable of machining the feature I have pointed out is ELECTRICITY, via a perfectly understood process called EDM (electric discharge machining) which is widely used for industrial purposes down here on Earth but also observed in space as no doubt being the origin of such things as “impact craters” and “cometary activity” (with the resulting coma). The “spiral” effects seen in the image are produced by the rotating action of the twin filaments of an electric current, generated by an electric discharge phenomenon.

          Look at that picture again, Jacob (but perhaps you didn't bother, such are your certainties). How would YOU (and other guardians/theorists of the standard model) account for this observation of obviously machined features on the surface of 67P within the framework of YOUR model?

          For those who are interested but who haven’t yet seen this observation or picked up on its implications, my original comment is here:

          • Jacob nielsen says:

            @THOMAS, I'm sorry if I am being to provocative. English is not my native tongue, and therefore I sometimes unknowingly use an unfortunate wording. You should know that I would be thrilled if it turned out you were right all along: 67p is a solid rock after all. I was chipped off some planet by a giant flash of lightning, that at the same time dyed it soot-black. The mass of 67p turns out to be grossly underestimated, because gravity is suppressed by an electrostatic (?) repulsion (didn't quite get that part). It would be great fun... Even if just in part, for instance: the crust of 67p is indeed a substance that could be best described as 'rock', or: gravity does not rule the mechanics of the galaxies, high voltage does. As you probably know it would come as a surprise to me, but I can tell you I would be thrilled! As would be the whole scientific community (I don't count myself in there) they would be, because their world would not then be shattered, but more complete. But we are not there yet: it works the other way round: If a new theory explains a set of phenomena in a simpler, more coherent way it replaces the old theory. The old theory is not replaced because it is getting old and there is a new kid on block. I realize you have a strong faith in a theory that feeds on electricity, so when you see a bright spot you think: could be it! Something hot and electric. I have no particular idea about the bright parts i Philaeas cave, but I tend to think of some of them as frech fractures. I too see the 'dotted pattern' that may resemble roofing nails, I just don't think: electricity did that. What I do think is: strange, could be an imaging artifact? or just something I am unfamiliar with? I other matters I am unbearable confident, that goes for gravitation and matter: I can't do what Andrea's team does, but I trust their toolkit blindly. I will cross my fingers for you, but I think it takes more than that. Besides the headline should have been: " Mupus found something hard beneath dust". The mention of ice caused a stir.

          • Steve Kasian says:

            BTW, that instrument has a name: "CONSERT"

          • Seedling says:

            That comment no longer exists, THOMAS. But I find it interesting that you assume your explanation is the only possible one and that the established scientific model has to defend itself against the ever-debunked pseudoscienctific EU model... when proper scientists are most likely still sifting through all the data rather then assume they are right and pick-and-choose whatever data fits their assumption.

      • Marco says:

        Hi THOMAS, I completely agree with you as far as the assumption of ice goes. The title of the blog is particularly presumptuous of the standard model. No "dust" or ice has been imaged on the surface by Philae, yet the proclamation is that Philae is in dust covered ice. Yet no evidence of direct electrical effects disturbing Philaes electronics is found either.
        The overall density, however, is not scientifically negotiable. And yes, I hope CONSERT data will specifically explain that. Basically, there is no way around it: The surface is not indicative of what is below. There is lots of empty space, somehow, below the crust.

        • originalJohn says:

          Marco, the overall density is indeed scientifically negotiable. There is no fundamental understanding in physics of gravity or mass. There are plausible theories that mass is not fixed for a particular body but related to state of charge. And measurements of the gravitational constant on Earth throughout the 20th century have shown it to vary by considerable amounts.

          The density figure for this comet nucleus is a glaring anomaly ( by a factor of 6 or 7 ) in view of the apparent hard, solid rock characteristics of the surface features. If measurements were to demonstrate that the material of the nucleus was solid and non porous rock it would be a serious red light for the scientific community.

          Too much I know for many people with closed minds but such is the way of progress.

        • THOMAS says:

          Hi, Marco.

          Glad that we can agree on some common ground, at least (and at last)!

          I take your point: no electromagnetic effects shorted out Philae's systems, to be sure. My surmise is that there was insufficient charge imbalance, after 4 months of Rosetta/Philae orbiting the comet, for discharge between the comet and Philae to be an issue any longer. (I’m deeply relieved that this was the case since otherwise we would have no information whatever from Philae to look forward to). The jury is out on that one.

          If Rosetta itself is now also in electromagnetic phase with the comet, though, it may still become a serious issue for Rosetta in the coming days/weeks/months, as it will increasingly be for the comet itself. In which case, the jury will come back in….

          As for your belief that the « overall density » is « not scientifically negotiable », however, we remain in total discord: there can be no “empty space” whatever below the surface, especially given the huge volume of empty space needed to meet the “40% of the density of water” requirement. Given the overwhelming evidence we have now acquired to prove the totally rocky nature of the comet (not only the photographic evidence, but also Philae’s huge rebound after its harpoons literally pinged off the surface), it necessarily follows that that figure of “40% of the density of water” has been obtained without integrating into the equations the defining electromagnetic properties of the comet. Once the findings from the CONSERT instruments finally prove that 67P is solid rock through and through, then the reality of the electromagnetic component of “gravity” will at last have to be acknowledged and we will, as a bonus, have a totally plausible explanation for the “anomalies” (according to standard theory) which have been observed in the trajectories of numerous space probes during banal flybys.

          I look forward to having further discussions with you (but don’t expect me to go along with you on the panspermia road, at least as regards the composition of comets …).

          • Marco says:

            I am not sure why you are so adamant in regards to the density. A low density doesn't disprove EU in any way. Insisting on solid, high density rock in the interior without the possibility of voids that make the correction, is a way for EU to look embarrassingly stupid.

      • stuartiannaylor says:

        What if this is some sort of deuterium / hydrogen blob that is a remnant of the big bang?

      • Scott cosmi says:

        I work with lyophilization of solutions under vacuum...freeze is often seen that solutions form a skin that is denser and harder than a porous middle...

    • Wayne Christensen says:

      I agree. Several scientists have remarked that the 'dirty snowball' hypothesis should be thrown out. The Thunderbolt Project ( offers an alternative theory. That this comet is solid rock. So far there has been no evidence for water ice.

      • MikeWhittaker says:

        Except the very low density would preclude solid rock ... unless it was pumice which is far from solid !

    • M. Lebert says:

      I'm still waiting for the comets are rocks-folks to explain the tons of materials evapoating from the comets when they heat up.

      • Star0bserver says:

        That is called plasma or the energy field of the coma that consist of two tails streaming off. One is a plasma ion tail and the other a dust tail. Through electrochemical processes the oxygen streaming off of the negatively charged body combines with the hydrogen rich solar wind and creates water throughout the coma as the comet gets closer and closer to the sun. The creation of water in this process creates light and causes the coma to brighten and tail to expand. Some comets like comet Holmes grew to a diameter twice that of our sun. As the comet creates this water, the ultraviolet strips away one hydrogen molecule leaving hydroxyls (H101)

        A hydroxyl is a chemical functional group containing an oxygen atom connected by a covalent bond to a hydrogen atom. It is sometimes called the alcohol functional group because when bonded to carbon in a molecule that otherwise contains only hydrogen and carbon the hydroxyl group defines the molecule as an alcohol, resulting in a name ending in -ol. A hydroxyl group bonded covalently to the carbon of a carbonyl group (-C=0) produces a carboxyl group (-COOH) that is the defining group of a carboxylic acid. When the -OH group participates in an ionic bond, the [-OH−] anion is called the "hydroxide" ion. From Wikipedia

        The reason the Comet seems to be dead is its position to the sun. It is not close enough yet to "light up" All asteroids can be considered comets as well, (google Lazarus comets) They are pretty much the same thing. They just have different electrical potentials. The ones that stay out in deep space longer have more time to gather charge from collecting electrons and not having the opportunity to discharge as often and these seem to put on more of a show where an asteroid in closer orbit to the star will balance its differential potential by being in the field of resistance for longer periods of time. Similar to what they did on the rosetta mission by staying in orbit to balance the electrical differential between the craft and the comet to avoid a electrical discharge. Comets and asteroids are pretty much the same thing with very similar compositions. That is to say chondrite or the results of a planetary collision or catastrophic destruction that a planet can endure or leaving it severely damaged through the electrical discharge and machining away of its surface materials. Search for "When planets gave birth to comets" No ice needed and the ORT cloud explanation is a mythical total bullshit explanation not based in reality but fantasy and delusions of a creative mind. They are not dirty snowballs period, but highly conductive electrically charged bodies.

        see."When planets gave birth to comets" or
        Episode 3 Symbols of an Alien Sky: The Electric Comet (Full Documentary)

      • George Canning says:

        Wait until it starts to emit the so called water. You will see it comes from edges points and scarps - not holes or cracks. Particles will be typical of that of planetary rock.

    • Sovereign Slave says:

      Good prophetic call, Jacob, and here's its fulfillment. Although the accomplishments of the scientists and this mission have been spectacular, absolutely laudable, and incredibly exciting, it does seem like ESA's ongoing demand that this "solid rock" is in fact cleverly disguised ice is boarding on irrational. Nothing in this article seems support the article's heading. It’s especially hard to imagine they didn't design a drill that could handle ice, no matter how hard, especially when ice is what they were expecting to find. Solid rock may be another matter though, which is obviously what we see in Philae’s picture and in my mind the more obvious conclusion as to the drill’s lack of progress. Yet we continue the "Where's Waldo" ice hunt fueled by an increasingly apparent faith based collective belief. I just hope that the future scientific discoveries aren’t presented in such an obviously biased manner.

      • Jacob nielsen says:

        Not ice as we know it, not rock as we know it, but 'coroice' comet rock ice: a rock with a low melting point, composed of many substances; silicates, water, organics, etc. Hard as hell when solid, mud or gravel when 'liquid' or 'dry'. I think it has been suggested numerous times in different ways, and 'coroice' I think, is a term used only once.

        • THOMAS says:

          Jacob, you should patent the term, just in case it turns out to bear any faint resemblance to anything finally discovered on Earth or on comets.

        • Sovereign Slave says:

          Jacob, I’m certainly not in a position to say you’re wrong. My point is that it would be refreshing to simply have the facts and the science results presented as is without the inevitable overlay of standard model mythology. There were three paragraphs of facts in the article above related to the science activities, the rest was pure speculation. And make no mistake, the standard model of the universe is totally based on imaginative speculations that are then based on other speculations and assumptions on and on. It is a many-decades-old creation story mythology which has supernatural characters even greater than the gods of old, and everything observed and encountered in the universe has been enslaved by it to the point where its hard to imagine its not true. But its still just a myth. Its just a myth. Its…just…a…myth.

      • THOMAS says:

        @Sovereign Slave: "I just hope that the future scientific discoveries aren’t presented in such an obviously biased manner."

        I'm becoming increasingly worried, in particular, about the non disclosure of the CONSERT radar data which must have proved once and for all that the interior of this comet is made of solid rock and is not the virtual void required to account for the "40% density of water" figure. Why is the CONSERT data not forthcoming?

        I'm getting a funny feeling that the CONSERT radar instrument will eventually be announced as not having functioned correctly (like the harpoons...!) and that, finally, the data they thought they had acquired has not actually been acquired (or that it is "unusable"...).

        Otherwise, I don't see how that data can be spun in the same way as the MUPUS "findings".

        • Marco says:

          Thomas, remember that CONSERT data requires a detailed knowledge of the exact position of both Rosetta and Philae at the time of the experiment. They have used this in reverse, from what they think they know about the interior, to hone in on a location for Philae, without confirmation yet. The data is there, and presumably, once they verify Philaes location, scientists will be able to piece the puzzle. I guess we are obliged to believe them, whatever they come up with.

        • originalJohn says:

          You could be right about CONSERT THOMAS but I hope not. I have wondered a similar thing about ions versus neutral gas in the jets. A simple measurement with preliminary results long overdue.

      • logan says:

        "...It’s especially hard to imagine they didn't design a drill that could handle ice, no matter how hard, especially when ice is what they were expecting to find."

        You have a 'Sovereign' argument here, Slave.

        But this was one of the last experiments, don't know if done on the V & A needed.

        Design was made under very clear assumptions. On the behalf of science as a discipline, it would be very interesting if those setting instrument specifications chat about it 🙂

        All of us should show the needed respect about what was accepted knowledge about comet dynamics at that epoch. (15-17y?). Also about the budget limitations of the time.

        • logan says:

          Also saying that Philae was not designed to land on 'primary' surfaces...

          • logan says:

            Surely there is a thermal profiling of Agilkia. That profile telling clearly that it is not simple, solid ice, what lays under that dust.

        • THOMAS says:

          @ Logan "All of us should show the needed respect about what was accepted knowledge about comet dynamics at that epoch. (15-17y?)."

          I have also stated this in several posts on other threads, going on to point out that the Rosetta mission was planned and launched before the observations of the clearly rocky, electrically active nature of other comet nuclei (in particular Wild 2 and Tempel 1) had been obtained.

          It is therefore indeed not surprising that the Rosetta mission engineers were unable to fully cater for the conditions they found on 67P, since they were still basing their design work on the "dirty snowball" model which the theoretical scientists were still clinging to at the time.

          The engineers have, despite everything, still done an amazing job.

    • Mr Grey says:

      or "there's a giant UFO craft stuck in ice!"

    • Mike Philbin says:

      my thoughts initially... exactly, so to speak.

      I don't put REAL MONEY on 'comets bring the oceans of Earth' in their fiery trails entering Earth's atmosphere. I mean, I really don't.

    • Steven says:

      No, it'll lead to it's surface rock with a "hidden" icy core. Got to keep the old myth of dirty snowballs alive, long after they died a natural death years ago. After Stardust and Deep Impact, there was never any reason to prolong a theory long shown to be wrong.

    • more like diamonds and graphite core and icy gas top layer. 7 out of 13 covalent molecules of rosetta contained carbon and impact crators all around the world contain diamonds which are made from carbon ... it has always been stated that the diamonds formed on impact however one can only imagine that these comet/planetoid fragments have collided multiple times and been exposed with the harshest of forces enouth to melt away the other elements and leaving behind the carbon to form graphite and diamonds

  • Sepp von der Olm says:

    I am surprised to read that MUPUS can be used again. I thought after using power mode 4, the "desperate mode" the tool suffered substancial damage.
    However, thank you for the update - looking forward to learn more about tschuri!

    • Daniel says:

      MUPUS is, I belive, three different instruments. There is the penetrator (PEN, whose hammering mechanism broke), a thermal mapper (TM) attached to the body of Philae and finally temperature sensors inside the harpoons. So I would assume it is the thermal mapper that they can expect results from if Philae wakes again. I suppose they might still get temperature readings from the penetrator rod as well, maybe?

  • Dave says:


    Its good to have some feed back so soon after an event.

    There are also many questions though. If its solid ice, then the density for the comet looks a bit low.

    Also if its ice, why have the other instruments, including Rosetta not detected it. There are plenty of areas where there is no dust covering, so there is a big surface area to search.

    I guess we need some corolating info from some of the other instruments.
    Phillae will hve plenty of surprises for us even though it only had a brief chance to collect data.

    • Ross says:

      Be weary of these press releases. The writers are in an awkward position between feeding the public information they demand without giving too much useful information away inside the "proprietary period."

      However, the title of this blog post really bothers me as it is extremely misleading. "PHILAE SETTLES IN DUST-COVERED ICE". The evidence, if you can call it that, is entirely indirect. If this solid ice is hidden only a gem millimeters beneath the dust, then how is there ZERO exposed ice anywhere? I hope these writers loosen their death-grip on the illogical snowball model.

    • louise seager says:

      If there is ice then there's water...we must send a second craft, is out there of luck David/ elle.

    • M. Lebert says:

      As far as I know even some of the high-res images that have not been released to the public very clearly indicate glittering ice. And some of the other instruments will surely indicate that as well. It's just that MUPUS released more info than the other teams so far, which btw. I am very thankful for.

      • Dave says:

        M Lebert,

        All that glitters is not ICE.

        Ice is so central to the std model, that if it had really been detected, on any of the comets it would instantly be trumpeted, not only as proof of the std model but as a huge success for the mission.

        The mission is a huge success with or without ice!

      • daposter says:

        oh yes, and looking at some ot the pics there are awesome powder ski slopes there 😀

    • Prof Harvey Rutt says:

      There is no reason to expect large areas of exposed ice.
      If it starts as a conglomerate of ice, solid CO2, other volatiles, and involatile material, as the volatiles sublime it will tend to concentrate the involatiles on the surface.
      Some of those will get ejected by gas jets, but it's unsurprising the surface would concentrate involatile material.
      Even on earth, in some areas you walk on a glacier on a layer of rock and dust and don't see ice.
      Whatever it is with a density of 0.4kg/L it must be porous. In fact if indeed it was rock, VERY porous!

      • Marco says:

        Hi Prof Harvey, I really do like your posts. They are patient, scientific and well thought out. I however find the word porous to be quite presumptuous as it implies small pores such as in powdery snow, pumice or aerogels that allows air or liquid flow, rather than the possibility of rather large chambers, hollows or honeycombed structure that may In fact seal off gas or liquid. Whatever it is, it has a net low density- some or all of the solids below the surface may be non- porous.

        • Prof Harvey Rutt says:

          You read rather too much into my use of the word 'porous'. As yes, we have no data on the structure leading to a density of ~0.4kg/L. What sort of scale size the voids have I have no idea.
          What is clear is that there will have to be a great deal larger void fraction if it is mainly rock with a density of 2.5-3 as opposed to ice plus some rock etc with a density a little over unity.
          Re the surface. The comet has been exposed to ablative processes repeatedly on passage near the sun. Each pass will tend to cause a concentration of involatiles on the surface as compared to the bulk. The processes which might expose deeper material will be utterly different on 67P to a glacier, and I would not take the analogy too far.

          Furthermore the comet is exposed to hard UV and the particle flux, which may cause some interesting organic chemistry.
          It would, perhaps, be a bit surprising if absolutely no ice is exposed anywhere; but that little is exposed I don't find remotely surprising.

          • Marco says:

            Cometary scientists have been using the word "porous" habitually as a fallback for any low density calculation such as the one for C-P. I would invite you to look up the word for yourself and see that it is based on a clear assumption of internal homogeneity. Imagine that you were handed a balloon and a piece of aerogel with the same net density and told that porous is a fair description of both of them based on the density, it would be equally rediculous.

      • Dave says:

        Hi Prof,

        I also have been on many Glaciers, yes the surface is often covered, but when its not covered You do see ice!

        And when the ice sheet moves and fractures, when you look down the fracture, guess what yo will see? ICE.

        We do have dust covered comet surfaces, but we also have large areas with no dust, also there are many features where a new surface is exposed where the instruments cannot detect Ice.

        So far there is no direct evidence of ice on the comet.

        I am more than ok if it has been detected but we have not been told, so until then, where is the direct Evidence ? (the numbers)

        Even with the lander on the ground with its instruments looking at what looks like a solid substance, not covered in dust, No direct evidence of Ice.

        • logan says:

          Hi Dave. You are right. But zero is not the same as undefined. It could show some little love just to tell the Reach Team: 'That data is undefined (or unknown) by the team'. SD2 Team have just done that.

        • logan says:

          My assumption -due to lack of updates in this issue- is that there are 'dirty' ices here and there. Visible, at small boulders and patches.

      • @Prof Harvey Rutt, referring to porous ice, Aero© chocolate bars come to mind. 🙂

        Near the surface of the comet, any ice would have been sintered, due to the heat and solar wind effects as it nears the sun. The surface ice would also have lost any volatile material, and what remains would be compacted without pores, and possibly mixed with rock dust near the surface.

      • logan says:

        Hi Prof Harvey. What about a super-extreme porous rock [Styrofoam level] filled with volatiles? [Of course volatiles no more at most of comet's sunny surface] [and allowing us for a moment no to think in the phenomenology] 🙂

  • frankebe says:

    "If we compare the data with laboratory measurements, we think that the probe encountered a hard surface with strength comparable to that of solid ice,” says Tilman Spohn, principal investigator for MUPUS."

    How about--the probe encountered solid rock?

  • Indira Montejo Lamas says:

    Thank you for keeping us inform. There was no way to have known for certain the comets terrain composition.

    From what I read. All is needed is power. And once the comets hopefully continues its trayectory. Philae would powered the battery.

    Cross our fingers, for that little fellow.

  • CAN Sr says:

    It just keeps getting better & better. How fantastic that all my life comets were heavenly bodies scientists speculated on and now practically every day I'm reading factual information about them from ESA + Rosetta/Philae. To all the scientists & Support staff at ESA involved in this amazing adventure......thank you for sharing your dreams, knowledge and efforts with the world.

  • Jon Hancock says:

    How do you know that the subsurface the probe was trying to hammer into was ice and not some kind of rock? The photo from the surface (with the foot of the lander showing) seems to show a large boulder, is that made of ice? Also, are we talking about water ice?

    Huge congratulations to all involved.

  • louise seager says:


  • Great article -- I did not know that there was ice on 67P. That's intriguing. Minor corrections in your last para -- "I guess we need some [corolating] (correction= *correlating* or *corroborating*) info from some of the other instruments.
    Phillae will [hve] (correction= *have*) plenty of surprises for us even though it only had a brief chance to collect data."

  • My corrections above are for @Dave in his comment, not for the author of the article! Sorry for the confusion! 🙂

  • Michael Reid says:

    Fascinated and hungry to hear more

  • logan says:

    So the dirty solid ice is there. Just below the dust. This news bring 'liquids' closer to both surface and argumentations 🙂 The blacker material to the left is a lot more 'organic' than the dirty ice you are describing 🙂

    • logan says:

      Hi Robin. Your foamy candy modeling is coming closer to reality 🙂

    • logan says:

      But until densities are given my mind sees a lot of adittional possibilities.

      • Robin Sherman says:

        As Thomas points out the CONSERT data should be the clincher. If however as I suspect Philae bounced off the head of the comet and onto the lower lobe or neck region only a limited cross section of the inside of the comet will be revealed. This was the reason Site C was not made the primary site. Agilkia was chosen in large part because it gave the best chance to get the best view using CONSERT. As we know that plan has been scuppered.

        A lot of doubt has been expressed about the "evidence" for the subsurface being made of a very hard icy material, based solely on the probes inability to penetrate the solid layer. The piece above specifically states that evidence from temperature mapping was used in conjunction with this data. The thermal properties of rock and ice are different and those observed match those of a type of ice. The subsurface was found to be hard therefore it is hard ice. It was hoped the probe could penetrate the surface to measure the thermal gradient. This probe was not designed as a drill, or to provide data on the hardness of the material. It had four settings and thus could only give a series of resistance to penetration readings analogous to the going on a racecourse. It was intended to "tap" the surface and operate in similar manner to sonar. The harpoons contained the measurement devices to ascertain the mechanical properties of the surface/subsurface as a part of the MUPUS suite of 3 instruments.

        Having thus ignored the evidence that is inconvenient to their case, the statement that the hard subsurface layer is rock is made without a trace of physical measurement or even visual evidence to justify that assertion as being fact. It is an opinion, one that is in denial of the measured evidence.

        The MUPUS team tell us the probe they used indicates the subsurface is hard. The thermal mapping says the subsurface is ice. The two together leads to the preliminary assessment that the subsurface is hard ice. There is no information to say what the structure, chemical composition, refractory content, mineral content is, or what organic molecules may or may not be present. By definition a preliminary assessment is one that is incomplete and not the final description, which is what we got. In the particular spot Philae settled the surface was found to be covered in a layer of dust that was colder than ambient and a hard subsurface layer with the thermal properties of ice lay beneath it. The whole rest of the comet could be covered in rock, ice or black truffles.

        • Marco says:

          Robin. Given the evidence, the fairest thing that can be said regarding ice is that ice of some description and mixture cannot be ruled out. I think scientists fear a loss of face if they just say that, even after many measurements that they do not know what it is. The convention is always to favour parsimony, keeping to incumbent models while they remain plausible given new measurements. There appears to be no visual confirmation from any cameras of loose dust being disturbed at this site. Not sure why they have, nonetheless, decided that the initial drop in temperature was from dust. I haven't heard much from the "ground truth" aspect. I guess it doesn't help that we do not know what the remote measurements are for this spot....

          • THOMAS says:

            Marco, you summed up the mission scientists' dilemma perfectly by saying that they "fear a loss of face". Beautifully euphemistic! They have NOT, however "DECIDED that the initial drop in temperature was from dust". They speak of TWO possible causes:

            “We think this is EITHER due to radiative transfer of heat to the cold nearby wall seen in the CIVA images OR because the probe had been pushed into a cold dust pile,” says Jörg Knollenberg, instrument scientist for MUPUS at DLR.

            In my book, the "cold dust pile" is a straw-man, created precisely so as not to "lose face" too soon. The most probable hypothesis in the scientists' view is certainly the first-mentioned alternative: "radiative transfer of heat to the cold nearby wall". A wall that is visibly, 100%, made of rock.

      • Kamal Lodaya says:

        Hi, From the DLR portal,
        the emphasis is mine. It is not clear to me whether "this landing site" in the last sentence refers to the final one.

        The instrument CASSE, which sits in the feet of the lander, was turned on during the descent and clearly registered the first landing as Philae came into contact with the comet. From additional data, the mechanical properties of Churyumov-Gerasimenko will be derived. SESAME's two other instruments suggest that cometary activity at this landing site is low, as well as revealing the presence of a large amount of water ice under the lander.

        • Kamal Lodaya says:

          More precise statement from DLR:
          The two other components of SESAME, the Dust Impact Monitor (DIM) and the Permittivity Probe (PP) experiments, performed measurements and sent data back to Earth during Philae's more than 60 hours of operation... The PP experiment used a number of electrodes to transmit alternating current through the comet surface and was able to detect that there is a large quantity of water ice under Philae.

  • Tim says:

    If it is ice, and if the lander comes back to life when it gets closer to the sun, it will be fascinating to observe the ice melting as the surface warms.

    Good work ESA.

  • logan says:

    "...Tilman Spohn says that MUPUS could be used again,..."

    That is extraordinary good news 🙂 🙂

  • logan says:

    To the Great Web Master:

    Could it be possible a module for blog search? Just if there is a rapid answer. Don't want to distract anybody 🙂

  • B says:

    Hearing Phailae running out of power after such a long journey was heart breaking.

    Regardless, it's a great time to be an astronomy / space enthusiast!

  • Vincenzo says:

    My fantasy for interpretation of the data has received an appropriate input: dusty state of coat... Any atom analysis? semi qualitative to explore composition and absence (presumed) of cohesion at +150*C apparent T?
    I share the posted hypothesis of structure of core, and wait for additional data with real interest...
    The received info is outstanding and coherent with the historical expectation... Organics with this spot are improbable... The formation of dusty substance on surface, fits with a mechanism of formation helped by progressive cycles of micro change of crystallization variety structures (f of T)...
    Thanks and patient waiting time...

    Forza e bravissimi!

  • JC says:

    This is really impressive work.

    Could you explain how the instrument is able to drill down effectively without Philae beeing correctly fixed to the comet, does it have some influence on the performance of the hammer?

    Thanks for your answer.

  • Ross says:

    August 1 on the blog,
    "ESA’s Rosetta spacecraft has made its first temperature measurements of its target comet, finding that it is too hot to be covered in ice and must instead have a dark, dusty crust."

    So many conflicting observations....

    It was too warm, now cold as it moves closer to the sun, no ice possible, to covered in ice, to no ice detected, to landing in icy dust. From fluffy and soft to hard as solid ice.

    I believe a literature review is necessary, at least for failed predictions which are sure to be observed... but then ignored.

    Just as the conflicting dats of Deep Impact showed a very hard nucleus yet it's small crater was speculated to be due to dust falling back down, "partly healing" the crater (lol).

    • Marco says:

      Yes. So much for "ground truth". Results are contradictory in the sense that at least for the data point of Philaes location, remote data comes to different conclusions, without much of a clue as to which assumption basis has been incorrect.
      Eg. Remote data conclusions about the top layer being "insulating" contradicts Philae's result where temperature appears to be quickly conducted through the solid wall.
      Is the assumption of the interior being frozen and solid incorrect?

  • Steven Bergens says:

    This is fascinating! One wonders what the origins of the water are. Can't wait for the mass spectrometer's results.

  • John Patrick Lee says:

    Fantastic achievement congratulations.

  • MikeWhittaker says:

    During winter of 2011 I noted that the railway platforms in Lund, Sweden were not fully cleared of snow/ice but gritted in layers. Hence there was built up a strong composite material after several weeks !
    Perhaps on the ISS in zero-G they could try creating a composite of regolith-like dust and water vapour at low temperatures, and checking its mechanical properties ...

  • Mike Mahl says:

    This entire event was fascinating! I've been a fan of space exploration since the beginning missions. Man's interest in space is only natural. I wish we'd turn our efforts towards Mars , being it's the closest planet to earth. I 'd like to see manned missions there in the next 10 years.

  • Moana says:

    One picture I saw of the Lander it had one foot in the air.
    So this has been corrected and its now resting on all three feet?

  • Mike Lentsch says:

    “If we compare the data with laboratory measurements, we think that the probe encountered a hard surface with strength comparable to that of solid ice,” says Tilman Spohn....

    In other words, we've got NO idea about what's going on anywhere, so we'll just presume that our dim observations match up with our old theory.....

  • slappy says:

    Wow it's crazy! So now comet looks like some porous sponge with hard crust???
    I can't wait for results from CONSERT!

    • THOMAS says:

      Nor can I. Those will be one of the "game-changers in cometary science" which the ESA mission scientist, Matt Taylor publicly referred to (if they are ever disclosed).

    • gnappi says:

      It´s like a termite mound: hard and dry on the outside and moist and tender on the inside !!!

      • logan says:

        Hi Gnappi. Don't forget the thermo-electric cooking [just happy guessing] 😉

  • Johan Prins says:

    jay! Hollow Earth theory finally proven in form of a hollow cometl, which explains presence of rock and low overall density? Jjust kidding!!! I hope Philae will wake up again, maybe it even can make it around the sun in that shady place, but will still get some more sunlight than now. I
    Could it get ejected from there, or is it pinned down now?
    I wonder if the PV panels drive the heaters directly, otherwise charging will only begin when the scarce sun heats the whole lander over 0°C. Many crossed fingers and a deep bow to what the various crews achieved. You made history!

  • anjin says:

    Cheers to the MUPUS team! That was awesome ! Well done - specially under those tricky conditions ! and keep coming with more details. Very fascinating !

  • Serban Laurentiu says:

    What does Philae intend to do in the next days, maybe weeks ?

  • Jose Gavila says:

    I am sure Philae will eventually wake up and bring more exciting data. Kudos to all the team for this incredible project!

  • Leo Vuyk says:

    Simple question : Why was MUPUS not able to hammer into solid ice?

    • THOMAS says:

      Because it was actually solid rock, just like the solid rock it took a photo of.

  • Gerry says:

    What rotten luck on the landing... ummm... landings! If I were on the team that designed the harpoon system I'd be attempting to approximate the conditions that *could* have caused the 'failure'. This may provide an insight as to what #Philae *did* encounter; particulates covering very, very, hard, impenetrable ice?... as against a 'friendly' mushy-like surface. Let's hope a future ray of sunshine (!) provides enough power that we can get images of the surroundings and proceed from there.

  • mike says:

    comet Bernice no hair theory newest constellation rotating non rotating charged non charged black hole mn(comet) backwards in time alphabet city

  • Bill says:

    My thoughts are that a comet is composed of the primordial star-stuff of the Solar System. A mixture of a clathrate hydrate (water ice) containing a full spectrum of the C-H-O-N (carbon, hydrogen, oxygen and nitrogen) gases, plus trace amounts of other gases, plus a variety of "volatile and refractory organics", whatever "organic goo" that was cooked up in the Primordial (or even pre-Primordial) Solar Nebula since the beginning of time. And mixed generously in are the olivines and pyroxenes (silicate minerals), whatever varieties crystallized from the Si-O-Al-Fe-Mg-Ca of the Primordial Nebula. The ices serve as the matrix for the silicates or _vice-versa_, depending on whether this is a dirty snowball or an icy dirtball. And all this is of pre-planetesimal chunks that accreted from smaller chunklets that have been forming since the beginning of time.

    Think of it as a big Cosmic S'Mores bar. Bite in and you don't know what you're going to get. Think of a world designed by MC Escher.

    And with a comet, this body swings by the Sun, partially thaws and simmers, then moves back to the deepfreeze til the next perihelion passage. Over and over again til it becomes a cinder.

    No wonder the Ancients were scared silly of these comets. They is some serious stuff....

    --Bill 🙂

  • Outstanding in all areas ,As Philae goes into hibernation Rosettta will give us the best view of a comet slowly waking up.Unforgettable times for all concerned , many congratulations from Chipping Norton Amateur Astronomy Group , UK

  • Annie Desrochers says:

    Can't wait to get more info on this, this is truly fascinating!

  • Bill says:

    And I just read on The Beeb that COSAC has discovered organic molecules:


    • Ian McWeen says:

      Thanks for that link Bill. I have been searching the web for more info but hadn't seen that one. This is taken directly from the BBC page:

      "The Philae lander has detected organic molecules on the surface of its comet, scientists have confirmed.

      Carbon-containing "organics" are the basis of life on Earth and may give clues to chemical ingredients delivered to our planet early in its history.

      The compounds were picked up by a German-built instrument designed to "sniff" the comet's thin atmosphere.

      Other analyses suggest the comet's surface is largely water-ice covered with a thin dust layer." (Dr Fred Goessmann).

      There it is folks. Water ice and organics. Please correct me if i'm wrong but are either of these discoveries mentioned anywhere in this blog? I read this site daily trying to get info and I have just learnt more in five minutes on the BBC than a couple of months here. Come on ESA. I think Logan suggested a search function for this blog. It might make it easier for us to find results.

      Ian McWeen

    • logan says:

      "...It's more likely there's sintered ice..".

      Continuous crystallization processes is my guess too 🙂

  • Daniel Marie says:

    thanks for the update. What does it mean for the ice to be more porous below? Does it mean mixed with rubble?

    • THOMAS says:

      This claim means absolutely nothing, Daniel.

      Concretely (and NOT theoretically…), in the thermally hostile, rocky environments typically encountered down here on Earth (as in the European Alps in winter, for example), we invariably observe bedrock at the BASE, then solid ice ABOVE it, covered by different types of snow, with the least dense type of snow (“la poudreuse”, much sought after by skiers in the Alps) at the very TOP. Above that, there is only THIN AIR.

      On 67P, strangely, standard theory would lead us to believe in the reverse order, just as in the topsy-turvy world of Lewis Carroll’s “Alice Through the Looking Glass”, where everything is portrayed as the exact opposite of how it appears in the real world and where the White Queen proudly boasts that “sometimes I've believed as many as six impossible things before breakfast ».

      On 67P, according to standard theory, the order is totally and literally reversed, just as in “Alice Through the Looking Glass, with the outer visible crust of rock on the surface, then below that “solid ice”, then (hypothetically) different types of “snow” and finally, in the middle, THIN AIR (!!!). The void in the centre of the comet nucleus is REQUIRED by the equations of standard theory. Otherwise, the measured density of “40% that of water” (which means that 67P would float on any of the Earth’s oceans like a Champagne cork) cannot be true (as measured by standard theory).

      (For those who know little about English literature, may I point out that Lewis Carroll was actually the pen-name of the highly respected, late 19th century, Oxford professor in mathematics and logic, Charles Dodgson, who wrote the two world-famous“Alice” books ostensibly to amuse two young girls of his acquaintance but also, for a more adult readership, to denounce what he already perceived as the risk of purely theoretical mathematics gaining a literally absurd ascendancy over the logic of the natural sciences).

    • THOMAS says:

      This claim means absolutely nothing, Daniel.

      Concretely (and NOT theoretically…), in the thermally hostile, rocky environments typically encountered down here on Earth (as in the European Alps in winter, for example), we invariably observe bedrock at the BASE, then solid ice ABOVE it, covered by different types of snow, with the least dense type of snow (“la poudreuse”, much sought after by skiers in the Alps) at the very TOP. Above that, there is only THIN AIR.

      On 67P, strangely, standard theory would lead us to believe in the reverse order, just as in the topsy-turvy world of Lewis Carroll’s “Alice Through the Looking Glass”, where everything is portrayed as the exact opposite of how it appears in the real world and where the White Queen proudly boasts that “sometimes I've believed as many as six impossible things before breakfast ».

      On 67P, according to standard theory, the order is totally and literally reversed, with the outer visible crust of rock on the surface, then below that “solid ice”, then (hypothetically) different types of “snow” and finally, in the middle, THIN AIR (!!!). The void in the centre of the comet nucleus is REQUIRED by the equations of standard theory. Otherwise, the measured density of “40% that of water” (which means that 67P would float on any of the Earth’s oceans like a Champagne cork) cannot be true (as measured by standard theory).

  • Guili says:

    Hi there,

    Since this comment will contain some critics, I want to emphasize that this has been a thrilling and well executed mission. I want to congratulate everyone for a job well done. Also, for the record, I'm a space engineer.

    My critics, now. Basically, there has been too much haste to communicate successes and results. We were watching the live event of Philae landing in my company and when I saw everyone cheering at ESOC, I was worried. I understood you had a telemetry telling you "touch", but the mission responsibles translated this into "we are at the surface of the comet". Well, considering the real deal was to stay attached on the surface vs touching it, this statement was prematurate. And of course, you were not on the surface but rebounding at 1km high. At that point, luckily enough, Philae went back to the surface. But imagine the consequences if philae would have rebounded to space after you announed you were on the ground ? ESA would have looked like a bunch of people not understanding what is written on their screen.

    With the drilling, the misommunication started again. This time we could read "the first drilling on a comet is now a fact". And I was like "oh really ?" You didn't know accurately the attitude of Philae on the ground, you didn't know how far was the comet surface, but you still announced that ou drilled the comet. What you should have said was "we deployed our instrument and hope it will have penetrated the surface but this will be confirmed later on". And again, surely enough, later events showed you celebrated much too early : no samples returned in the oven: no drilling.

    And here comes MUPUS. I've been following their twitter account. The more the hype around Philae, the more twits were embarassing : tweets about "oh I'm so tired working on saturday", " I don't have 4G", "I need a bratwurst". Could you please forward them this message : for personal tweets, use your personal account, not the account of an instrument on a mission paid by the taxpayer. I felt like the scientists behind MUPUS really wanted to attract the light to themselves. In light of this, I have a different reading from this blog entry : again, you didn't penetrate the surface. You conclude that the surface is very hard. Well, are you sure again that you reached the surface ?

    So, my advice, take it or leave it : improve the control on your statements/communications, don't rush announcing successes when you are not 100% sure.

    Makes me think it is a very bad habit: remember the latest Arianespace/Galileo launch, it was announced successufull until NASA announced it was not. We looked so stupid.

    • THOMAS says:

      @Guili: Thanks for this insight. I honestly thought it was high-level spin. Of course they didn't "penetrate the surface", they just pushed Philae up a few centimetres because the rock was too hard to penetrate (and Philae's uncomfortable position had not been planned for, for obvious reasons...).

      I repeat what I have said many times before on this blog: the ENGINEERS have done an unbelievable job during the design and operating phases over the years in getting Rosetta and Philae where they are and in sending back to Earth all the raw data.

      I do NOT share the same view of the "scientists", however (with the possible exception of Matt Taylor who has publicly admitted that the findings already achieved will prove to be a "game-changer in cometary science": we must wait to see exactly what he meant by that enigmatic statement). They are still defending the standard theory and will only grudgingly (if at all) disclose the more compromising data (e.g. the CONSERT data, already definitively acquired, on the internal make-up of the nucleus).

    • Jan says:

      thanks for your realistic attitude.

      Many congratulations to the team. As many others I've been overwhelmed by amazing results already achieved by this great project. Obviously we all want to hear good news.

      Despite I'm also slightly disappointed by some formal aspects of the affair like interpretation of findings you described, social-networks hype, or rather poor quality of A/V transmissions during Friday hangouts.

      Nevertheless I've been eager of any upcoming news. Hopefully some "hard", realsitic data will be provided to allow the community to base it's debate on something reasonable.

  • AB says:

    Thank you information. It is great to hear that MUPUS (Made in Poland at Center of Space Research) is in good condition at so low temperature (-153 deg. C). Well done for everyone involved in this project!

    By the way is it some place to check ststus of the mission and read data from Philae?

  • Bas van Duijn says:

    I am so proud that humankind has pulled this off! Great example of multidisciplinary and multicultural teamwork. Proud of ESA! Also thumps up for the excellent media coverage. Makes me feel part of it!

  • JohnM says:

    The BBC Sky at Night programme reported that the hammer probe - presumed to be MUPUS broke because the surface was so hard. This report indicates it was still functional when the lander went into hibernation. Which is correct ?

    • THOMAS says:

      I no longer trust the BBC that much for reporting science (especially "climate science"), but in this case they've probably got it dead right.

  • Ingo Althöfer says:

    Question from a greenhorn:
    How hard is water ice at -150 degree Celsius
    or below?


  • Cometstalker says:

    Its cold and hard, this does not mean ICE of water. What was tested in the laboratory CO2 ice? Ice of any mixtures? How cold? I bet no one knows just about anything yet of what this comet is all about. Lets wait for some proper science once Philae wakes up again.

  • Bram says:

    Why solid ice and not plane rock?

  • ASauler says:

    Ice or Stone? Was it giving off the typical "Comet" tail? Whatever it's made of, we've landed on it (positively mind blowing), and we're going for a ride around the Sun!
    When we get close to the Sun, will we take pictures of the Sun also?
    This is going to be some trip!

  • Maarten Roos says:

    Excellent work and very exciting science!!

  • Wayne says:

    Still clinging to the dirty snowball theory? I doubt it. This thing is blacker than coal, it appears to have been exposed to intense heat. I think the electric universe theory is more sensible. It does explain the strange formations on Mars that everyone speculates about and could be how this remnant was formed. Pure speculation on my part, like the dirty snowball theory.

  • Anthony says:

    Remarkable, looking forward to the upcoming discoveries when Philae gets it's batteries up again. This is huge.

  • Craig Jenkins says:

    Trying landing one in Buffalo right now 😉

  • Robin Sherman says:

    I don't wish to sound sarcastic, but a "preliminary assessment" at last. Thanks Emily thats excellent work, some information, but still with some amount of doubt and uncertainty to permit further speculation.

    The term "ice" here, I presume refers to a mixture of frozen volatiles, mainly Water and Carbon Dioxide, but the other volatiles detected already in the coma, also. From it's appearance in dust free areas, the specific ratios of ingredients, including mineral dust, have a significant affect on the external texture and the mechanical properties of the solid.

    So what sort of structures and mechanisms can we come up with to explain this "Malteaser" like structure of the comet? A hard solid crust encasing a very light, porous interior.

    First conclusion, the comet is not a continuous solid lump of volatile ices and dust, the so called "dirty snowball". We sort of knew that anyway from the density figure.

    Accretion of material of various shapes, materials and sizes is the basis for other theories for the formation of the comet. If the comet is made up of say a dozen or so very large lumps surrounded by accumulated ice and dust, this would imply the majority of the mass of the comet is located inside the comet and the outer surface would have to be very light and porous. Not so. This model then, seems to be ruled out too.

    So too would a collection of medium sized objects, in the order of tens of metres in size, the gravity of these objects would be significant enough to tend to conglomerate into larger lumps in the porous, powdery, almost fluid matrix, that would be required to still give the observed density and a solid crust. The majority of the interior would have to be hollow. the larger clusters of objects would be like peas in an almost empty pod, leading to all sorts of rotational fluctuations and irregular spin, also not seen. ESA were very happy that the plane of rotation of the comet was very consistent, very little "tumbling" could be seen. The change in the rotation period of 67P is more likely to be due to changes in mass distribution following large mass loss during the comet's last close approach to the sun.

    This leaves the accretion of a myriad of small planetesimals of the order of centimetres in size within an icy/dusty matrix. Gravitational consolidation of this material would be very slow and balanced if not overcome by centripetal force ensuring a more homogeneous spread of the larger planetesimals. Denser materials may well travel through the interior to collect at the extremes of the object, leaving the lighter more volatile material in the middle close to the axis of rotation. The collected denser material at the ends of the comet would then start to induce tidal effects on the tiny dust and ice particles of the matrix. The result a dumbbell shaped object, seen in a number of icier bodies examined previously. Such a density distribution and very loose conglomeration could give an overall low density if the movement of materials is restricted by a surface crust. So a plausible model if you can account for the solid crust over the whole comet, in the absence of external thermal energy. This comet spent most of its evolution outside the orbit of Jupiter and the vast majority of comets way outside the orbit of Neptune.

    So the crust has to have been formed from some internal source of heat to melt and consolidate it. The size of 67P, not to mention the density, eliminates a radioactive internal heat source of sufficient energy. Tidal heating may occur in a few specific bodies to provide enough energy to create cryovolcanism and extrude a surface crust, but this would not explain the general case of billions of other comets in the solar system. Another source of energy is the Kinetic Energy of impacting objects hitting the comet, penetrating the interior, tunnelling through the low density material and heating up the interior and directly allowing heated gas, liquid and solid to travel up that tunnel to the surface powered by the rapid sublimation of material surrounding the tunnel. Once at the surface this material is deposited as cryolava to make the crust. This process would also allow the homogeneous mixing of ice and dust and remove more volatile gases and ices from the surface layer, making it far less porous and concentrate the more refractory, harder ices on the surface.

    Long time readers of this blog will have read this conjecture before based on the volcanic appearance of the surface terrain. The evidence that the surface crust is probably ice or a mixture of ice and dust, is some tangible evidence for this scenario, though its hedged assertion that it is preliminary conclusion means the conjecture is only a little less speculative.

    Others surely have other mechanisms for the creation of the crust, I would be interested in other possible scenarios from those with more specialist knowledge.

    • Ross says:

      I believe that comets are the byproducts of planetary-wide discharges. The arcs of plasma extract enormous volumes of rock from the rocky surfaces, emitting numerous charged rocky bodies into space along with a scar on the planet. This comet is not primordial and was not gravitationally accumulating to the size it is now, only to be eroded by the sun. It is a mountain, devoid of all interior ices, leaving a volcanic resemblance.

      Comets were feared by ancient people as devastating events which rained fire and oil. This sounded ridiculous when filtering your thoughts through a dirty snowball model, but an electrically active body with a coma full of hydrocarbons... we're getting a bit closer to reality.

      So review all of your observations at face value and plug them into this perspective and see if you achieve the same correlation that I do.

    • THOMAS says:

      @ Robin Sherman: "Others surely have other mechanisms for the creation of the crust"

      There's no crust, Robin. It's plain rock all the way down and through and through. The radar results from CONSERT will prove as much.

    • logan says:

      Hi Robin:

      "...a collection of medium sized objects, in the order of tens of metres in size, the gravity of these objects would be significant enough to tend to conglomerate into larger lumps in the porous, powdery, almost fluid matrix, that would be required to still give the observed density and a solid crust."

      Remember the "rocket launchers"? I speculate those are your medium size objects (made of 'core' material). As regular objects they are, conform another organizative level: the superstructures.

      • logan says:

        The superstructure 'matrix' being secondary, metamorphic material.

    • Ross says:

      No offense to Emily, but I'm a bit disappointed that the AMA doesn't include any of the project scientists. If her writings on this blog are interpretive of the quality of science we are to expect during the Reddit event, then I'm not going to bother getting exciting to read more about icy dirt balls, dirty snowballs, or any combination of these terms

      • logan says:

        Hi Ross. Emily is talking there on the Behalf of the Planetary Society. Assuming his responsibilities. Emily is doing the best of the best polished work at the ESA OutReach Team, too.

      • logan says:

        I'm nobody here Ross. No intention to apply any pressure to free expression here. The most planned of this kind of endeavors is fully stochastic and public discourses and lexicons about space are still infantile. Completely sorry about my upset a minute ago.

  • David says:

    Philae will surely discover that P67, like all comets, are actually asteroid-like bodies. They are not dirty snowballs or snowy dirtballs, or any kind of snowy object at all. They are essentially asteroids with pockets of interstitial ice.

    That this is so is a long-time prediction of the satellite model of the late Tom Van Flandern, former head of the celestial mechanics branch of the U.S. Naval Observatory. P67 is an asteroid. It's too bad the science team was banking on encountering a fluff ball instead of a rocky object. Otherwise, the lander might have employed a tool strong enough to penetrate P67's surface!

  • tim smith says:

    How is Rosetta able to keep in orbit?

  • John Pescod says:

    Why the stubborn idea that it is ice when all views rosseta has photographed show rock and dust. Later it will be realised that comets and asteroids probably stem from the same source and are not things left over from the formation of the solar system.

  • Cathryn Easthope says:

    Thank you for this. I'm still not entirely sure of the disposition of Philae on the surface, but I imagine that if the hammer is facing downwards, that it must be fairly upright.
    ESA are often quite circumspect when it comes to releasing information (which we European taxpayers pay for) so a blog like this is very welcome.

  • Hansart says:

    To echo the comment made by Sepp von der Olm, could the MUPUS team clarify whether the hammer is still functional or not. I have seen on Twitter that the hammer was destroyed, after using the "desperate" mode 4 power. Thank you

  • Jimmy says:

    It is not ice, it is solid rock. (good call Jacob). This is obviously a rocky body. If you want to know what's in the core of Churry, just look in the middle. The core is completly exposed. It's time to quit scraping to verify old theories and time to start observing what is right in front of us.

  • seema says:

    well done Philae...amazing. Just waiting to meet you in you Philae. Sleep tight on icy comet.

  • dnussb says:

    Maybe it's only lack of information, but being a sceptic and as a non-professional, I find that results of hammering and drilling subsurface experiments have little reliability but are even missing, due to the lander's still unknown position and orientation and the overall lack of controlled fixation. Regarding MUPUS, as I understand the lander's orientation changed with deployment, and regarding SD2 I can easily imagine, that drilling went to empty space.
    But, I'll wait for the whole paper and as for now, it's not the end of the mission.

  • Ian Stirling says:

    Dave - with strength comparable to that of solid ice,' - I think was the comment from the actual scientist.
    The writeup seems to take this and assume it's actual ice.

  • Ed Whitney says:

    What kept the lander oriented correctly during and after the bounces? Yes, an unbelievable feat. I am glad to see it happened in my lifetime. How did we get this far this fast in 100 years?

  • Joao Prates says:

    Can someone please explain this paragraph:

    "Because part of the MUPUS package was contained in the harpoons, some temperature and accelerometer data could not be gathered. However, the MUPUS thermal mapper, located on the body of the lander, worked throughout the descent and during all three touchdowns."

    What does ESA mean with "WAS contained"? When did we lost the harpoons??? How and when did that happen?

    I had the idea that the harpoons had failed to deploy, nothing more than that. Having lost them is news to me.

    • THOMAS says:

      The MUPUS temperature data from the harpoons could only have been gathered if the harpoons had actually got a grip on the surface as planned. Instead, the harpoons bounced off the rock they encountered (hence Philae's 2-hour long rebound...), so the information was never recorded.

      • ptr says:

        actually the harpoons didn't fire...

        • THOMAS says:

          That was ONE version among several others. It was also stated that the harpoon CABLES were successfully reeled in...! Which clearly means that the harpoons were fired, didn't get the planned grip and were then reeled back in.

  • Brian says:

    Where are the promised pictures from the lander as it was bouncing around from point to point before it came to settle down for the last time?

  • Paul says:

    Perhaps the inner core is warmer than the surface, due to pressure? As the comet is approaching the sun, material from inside is molten, channelled through veins and released by vents on the surface, leaving the comet with an "empty stomach". This would explain the lower-than-expected mass.

    My second guess would be, that the ice is made from a lower density material than water...

  • Gordon Jenkins says:

    Ice? What kind of "ice"? Amorphous ice? Low Density amorphous ice? High Density amorphous ice? Very High Density amorphous ice? Ice one h? Ice X? Ice XV? Ice vee one one? There are many types of ice and each one tells a different story of comet nucleation and formation. Is the comet ice like a geode (hollow inside) or like a glacier? Did it form by nucleation or deposition or by rapid thermal cooling that you might expect from a collision between two or more deep space objects?

  • Gordon Jenkins says:

    Ice? Low Density amorphous? High Density amorphous? Ice one h? Ice XV? Ice VII? Ice X?
    What kind of ice? Is at all one kind or are there ratios of two or more different ratios at depth? Ice matters! Different kinds of ice in contact can lead to catastrophic avalanches. In space, ice can form by vacuum vapour deposition, rapid thermal cooling, rapid depressurization, chemical processes, etc.

  • Gordon Jenkins says:

    What kind of ice is Comet 67P/C-G made from?

    • THOMAS says:

      No ice at all, Gordon, just the rock which we see everywhere.

    • Andrew R Brown says:

      Hi Gordon,

      The predominant water ice, perhaps with some ammonia ice makes up the vast majority of this and all other comets.

  • originalJohn says:

    When a probe fails to hammer itself into a surface it is unreasonable to conclude it is hard therefore it must be ice, when other hard things exist, like rock..... particularly when it looks exactly like rock.

  • Bill says:

    I just read a paper on the Philae Harpoon Anchoring System:

    Seemed to be well-thought out system with redundancies.
    Have we heard anything on the telemetry for it? I figure that the gas-thruster didn't fire and with no hold-down thrust the harpoon kicked Philae back off.


  • Al says:

    If the surface is so much harder than expected, is it possible that the harpoons deployed but bounced off? Or is it known for sure they didn't work?

    And if they didn't work, has a reason been determined?

    Congratulations to all involved!

    • Paul McMahon says:

      I was wondering if the harpoons not working was a blessing in disguise. With the comet being reported as being very hard could/would the harpoons have rebounded and done some serious damage to the lander?

  • YolantaH says:

    Phenomenal achievement, well managed public outreach.
    Future of Rosetta suggestion: After comet comes back what's the possibility of Rosetta hibernating until the next P67 flyby? Does it have or can it store enough power to me moved to observe something else between the Mars / Earth space?

  • Dorisvaldo says:

    I would like what is the gas pressure on comet surface?
    thanks for any reply.

  • Frank Dooley says:

    The comet landing is a significant step for humankind! I am reminded of T.S. Eliot's words:
    "We shall not cease from exploration, and the end of all our exploring will be to arrive where we started and know the place for the first time."

  • Carmine says:

    If there is ice below the dusty surface, does that mean that water has been detected on or below the surface of the comet?

  • rowby says:

    I am sure the excellent scientists will be able to take advantage of the data gained in the 3 bounces to find some unexpected fascinating science.

    All of this is good. Let's hope as the comet travels closer to the sun, and perhaps wobbles a bit, Philae might wake up.

    We'll see -- in the meantime, bravo to the dedicated geniuses at the European Space Agency for their amazing work so far!!

    From Los Angeles...


  • mark says:

    Once the rosetter orbiter has follow the comet
    around the sun. What will happen then. Will it conitune to follow the comet.

  • This is a question for ESA. I read in another article @ Space(dot)com that 'ice' on a comet may refer to various compounds, not just water ice. For example, the frozen state may refer to ammonia, carbon dioxide, carbon monoxide and/or methane as well as water. Have the instruments on Philae been able to detect any of these other compounds in the hard, frozen material underneath the dust layer?

  • Coacervate says:

    Could someone help me find journal articles when they are published? Is there somewhere a list of publications from science teams?

    This has got to rank among the greatest science acheivements in human history. And now more than ever, I believe you help elevate humanity from the terrible depravity that brings us all down. So sublime. Godspeed Rosetta/Philae

  • Sajid Rabbani says:

    There must be some technical reasons why Rosetta could not come more closer to the comet and rotate around here and there in order to find Philae's exact location! !!

  • daposter says:

    very interesting, how did yhou measure the stress-strain curve to come to the conclusion that what you see is ice?

    That ice is very cold, much colder than any ice we encounter on earth except in your laboratory where you tested the response of -120some Celsius ice?

    I would agree it hit something 'harder', but what it is I'd be very careful. This is an agglomerate of pebbles of rock, ice cubes, black dust (like moon dust?)...

    everything in space seems to turn black after spending time in that radiation, including parts (metal) on that moon lander one of the Apollo did visit...

    I know, there are people eager to prove their guess that comets brought water to earth and are 'dirty snowballs', but is this 'something like ice' not like leaning a little too far out of the window....

    something hard of not yet determined nature, maybe?

    (you did test your hammer on minus 120some Celsius ice before and have data to compare, right?)

  • Robert Johnson says:

    Sounds like Philae may have been wedged in tight somewhere, if the hammering of MUPUS didn't push them off the surface.

  • PAK2 says:

    Just a comment about Philae becoming active again. Several statements after Philae landed seem to imply that he is destined to remain mostly in shadow. Actually, one wouldn’t expect Philae to remain in shadow unless he is shielded by terrain in multiple directions . The rotational plane of the comet is tilted at a large angle to its orbital plane around the Sun. Assuming the rotational axis doesn't drastically change direction, most areas of the comet should be well illuminated during some portion of its orbit (for example, the side of the comet in shadow now will become the lit side as it swings around the Sun). Hopefully, Philae will have good sunlight for a lengthy period later in the orbit.

  • Macro says:

    Next lander should be designed with 6 or more spider like legs to allow movement across whole comet body. At 1 gram weigh don't have to be extremely powerful, and being few meters long, with grippers at the end (maybe hand like ?) could serve also as practical "hands" to grip instruments, dust off solar panels. Could also release tether like thin extra strong line dangling of the comet km into space...Centrifugal force should keep it there. BTW 3D printer should allow to print out other tools and items at will using comet raw materials.

    • Guili says:

      "Hands" mechanisms usually contains hinges and bearings which are extremely difficult and prone to failure when operating in deep space. They are also very costly, would require a dedicated thermal control etc, etc.
      3D printing is being experienced in micro gravity on the ISS. Using comet raw materials to print should be possible only if know all the properties of this material in advance, which is not the case.

  • SoZa says:

    How are things like "solid shell", "ice" or "rock" be consistent with a density of the comet around 0.4 ? Is it due to vacuum and low temperature, or the very low gravitational force ?

  • Edward cox says:

    the landers total weight vs the strength of the pen hammer movements would result in the landers inability to do anything to a hard surface but vibrate and lift the lander away. No drilling possible much like what happens in Zero g with an un anchored drill. A near weightless lander cannot deal with the torque of the drill.

    • THOMAS says:

      @Edward: The only way the drill could have functioned properly is if the harpoons and ice screws had managed to anchor Philae tightly to the comet surface on its first landing.

      That didn't happen because the harpoons bounced off the rocky surface and the ice-screws then drilled futilely into the near vacuum which Plilae flew through for nearly two hours after rebounding.

      Philae was indeed "lifted off the surface” of its final resting place by the drill, as a final desperate resort to get something from the MUPUS instruments. The drill obviously couldn’t penetrate anything (and especially not the rocks Philae finally landed in the middle of).

      The supposition about Philae "settling in dust-covered ice" can thus henceforth safely be taken with a proverbial pinch of salt.

  • Adolfo says:

    Most people report here in this blog that the material in the surface it is made of rock instead of ice, take into account that a mixture of ice and dust could give to the formation of a structure as solid as concrete. Just make battered egg mixture with ordinary sand and let it dry and the result will be a compound as hard as concrete. It is not surprising that the hammer of MUPUS went broken in the case the ice of the comet is formed as a mixture of dusty material with ice in their insterstices as an amalgamate.

  • Koos Hollema says:

    I was also emotionally relieved, that Philea landed
    on the comet and congratulate the clever scientists
    with their splendid successes.

  • Dave says:

    Ice or not will clearly not be settled by the hammer data alone. The difficulties with seemingly not penetrating, could also be the problem with the drill, was it turing in space or was the torque consistant with penetrating the surface? After all the Comet looks to be at a stange angle to the ground.
    I think most people what ever their pet theory would of expected some ices (but ices of what?) somewhere on the Comet.
    However up to now, instruments have not detected ice on the surface, not on the surfaces that look to have recently lost their dust, or the large areas that dont look like they have never been covered in dust. So how do we make the leap to ICE when the hammer hits something hard?
    I am happy if there is ice on the surface but there is little or no data to suggest it is there so far.
    The other strange comment is that one of the reasons given for the change in temperature of the probe could be that it was pushed into a cold pile of dust?
    from the pictures at the comet location, we can see the surface has many features, but piles of dust dont seem to one of them, there are some piles of gravel but mostly it looks pretty solid.
    I am confused, and beginning to doubt that that the data from both the drill and the hammer is telling us anything at the moment.

    • THOMAS says:

      Carry on doubting, Dave, you're on the right track!

      And what could have "PUSHED" Philae "into a cold pile of DUST"?

      "PUSHED"??? What physical force could have "pushed" Philae?
      "DUST"??? According to the photos, Philae is surrounded by ROCK.

  • cornet françois says:

    If philae is not strongly fixed how could a drill could be used considering the very little weight of the lander on the comet.

  • Adolfo says:

    First of all, I applaud the outstanding achievement to soft land a probe in a comet, but I have some critics to the public release news.

    From the lack of scientific results announcement this is my guess on the results obtained so far.
    - MUPUS hammer is broken (I doubt it would be used after awakening)
    - SD2 drilled on empty space (no sample collected) probably due to the soil being farther than SD2 full extent
    - COSAC functioned with no sample
    - PTOLEMY functioned with no sample
    - APXS cover was closed (no results)

    I think it would be very difficult to come to a conclusion about the composition of the cometary material in the surface.
    Ice covered by dust is something quite superfluous and seems obvious from CIVA pictures.

    I see how bad is the ESA communication channel, with lot of contradicting messages, I hope this would improve.

  • David Allon says:

    harpoons did not catch, screws did not engage, MUPUS was broken... must be much harder than expected. Have we met Arthur C. Clark's RAMA?

  • Guy Gibson says:

    Basiclly a block of ice as always expected but as we have now seen that during the 4.6 billion years that 67P has been looping around the sun resulting in a recuring cycle of warming and cooling of the comets surface, that this has produced a hardened type of "Super Ice".
    Added to this, the millions of collisions with asteriods and other proplanet debris, the impact of the comet upon these objects would instantly melt thier "ingredients" into the ice. On seeing the photo of the "rocks" around the lander one can imagine the forces that took place to produce such a catastrophic chaos of materials.
    I´m convinced that there would be elements that would be new to science on these incredible objects.

  • Marco says:

    Great Achievement! Its good to see the first real measurements coming in, like what the comet’s surface is really made of. Looking forward to see more!

    • THOMAS says:

      @ Marco "Its good to see the first real measurements coming in"

      What "measurements", Marco?

      Sorry, they must have escaped me (and not only me apparently, given the distinctly critical tone of the majority of the comments posted on this thread so far).

      Just take a look at the very recent update on this blog "DID PHILAE DRILL THE COMET?":

      I believe it's called "back-tracking".

      Like you, I'm "looking forward to see[ing] more!" (but presumably NOT for the same reasons...).

  • Neil Wilkes says:

    To continue with the "ice" claims is insanity given the images we have, and I do not believe there are any images that show "glistering ice" as stated above otherwise they would have been touted far & wide as "proof of the model" and the images I have seen & downloaded all show a landscape that could easily be the Moon, Mars, or even a desert in this planet (if there were an atmosphere) this giving a lot of credence to the EDM theory of cometary origin - which makes a hell of a lot more sense than the hypothetical & utterly unproven "Oort Cloud" theory.

    Another worrying aspect to that claim is "why are there images we are not allowed to see"? Who paid for this in the first place?

  • Bob says:

    Does a comet rotate the way the earth and other objects in space do?

  • Andrew R Brown. says:

    Could you imagine a game of Rock, Paper, Scissors with an Electric Universe woo?

    It would be ROck, Rock, Rock 😀

    Could you imagine an Electtric Universe weirdo in a bar?

    "Please can I have a vodka and tonic with rock" ? 😀

  • Solar Panel says:

    I remember during one briefing from mission control center in Darmstadt, Germany a mission operator said that Philae needs about 6 hours sunlight to charge properly its batteries and operate and now it gets maybe 1,5 hous. Even if the solar panels get sunlight only 1,5 hours they still should become fully charged in 4 days? Why that has not happened, i.e. why the probe is in hibernation? Probably the panels became covered by dust? Then it is not likely to operate even closure to the sun at later stage?

    • Adolfo says:

      The reawaken sequence of Philae includes a pre-warm phase by the activation of heaters that consume power, once the temperature of Philae and specially the electronics and batteries are in a proper level then the recharging sequence will start, that is the reason Philae is in safe mode and does not charge batteries with 1.5 hours of sunlight that far from the Sun. The solar constant at that distance is very low several tenths of Watts per square meter, insuficient to maintain heaters on enough to warm the Philae enclosure.

    • Prof Harvey Rutt says:

      It requires a certain amount of power to keep the batteries warm enough to function. Until that threshold is passed, they won't charge. Once above operating temperature, your argument applies, approximately.

  • Cesar says:

    Wow, the McCanney School of Phony Science and Crackpottery is preparing a lot of cometary scientists ready to do their "science" in comments...

    • Are you instead referring to Jim McCanney, whose "theoretical work additionally stated that comets were not dirty snowballs, but were large electrical *vacuum cleaners* in outer space. The comets were drawing in vast amounts of material by way of powerful electrical forces and there was potential for very large comets capable of disrupting the planetary structure that was already in place" -- ?

    • Andrew R Brown says:

      There are some dreadful posts being allowed on what is supposedly a science board on here.

      It's as bad as all the nauseating Nibiru hoax, Electric Universe hoax, UFO hoax, etc videos on YouTube. No wonder why Europe and USA are losing ground to China, India, etc in science.

      • THOMAS says:

        @Andrew R Brown: "dreadful" from whose viewpoint?

        It's not at all an issue of the aging Western World losing ground to the youthful eastern economies. (I suggest we leave politics out of the debate, anyway since, as you say this is supposed to be a "SCIENCE board").

        It's more a case of the natural sciences regaining their rightful place as the true basis of correct scientific method and relegating mathematics to its rightful place as an indispensable tool to set up the required experiments and help to interpret the results obtained.

        The mathematical constructs/variables/fairy dust invented just to make the equations work in the way the master theoreticians of the time require them to work ("cosmological constant","inflation", "black holes", "dark matter", "dark energy", etc. etc.) have nothing whatever to do with the real world as we observe it.

        I'm absolutely confident that, as ESA mission scientist Matt Taylor has already announced, the Rosetta mission will indeed turn out to be a "game-changer", whether the supporters of the standard theory like it or not.

    • Robin Sherman says:

      Devil's Advocates?

    • Adolfo says:

      To Cesar.

      People are not doing "science" in comments, they are just airing their frustration about ESA policy to hide Rosetta/Philae results several months arguing their pre-proprietary period for just a bunch of scientist, even that the taxpayers paid for that mission.

    • Njoroge Gitonga says:

      Try reading some of these comments with an objective mind because they contain some interesting insights. In time the theory that states comets are made of ice will rank alongside, the earth is flat thesis and the earth is the center of the universe story. The latter two dogmas were held as the bible truth by scientists in the medieval ages. I believe Galileo was even killed by the medieval church for stating that the earth was not the center of the universe.

      Debunking commonly held but false scientific dogmas is very difficult. The debunked scientists often get personal when their theories are challenged and proved to be false. Indeed they even have the publishing powers in academic journals to prevent unpopular but correct ideas that disprove popular myths from being published.

      Believe me the dirty snow theory of comets is about to be thrown out of the window in spectacular fashion by the Philae lander and the Rosetta orbiter.

    • logan says:

      Hi Cesar! Welcome 🙂

    • Jacob nielsen says:

      Yeah, you should contribute too. It takes a lotta wrongs to produce a right, and with all the wrongs in here, some rights should come along. Somewhere. Eventually.

  • Guili says:

    I hope the reason for chosing to explain the telemetries by "The surface is so hard, what a discovery !" vs "We unfortunately didn't penetrate the surface" has nothing to do with the temptation to put one's name on a scientific paper to secure one's career.

    It is obvious that with Philae unattached to the ground, the MUPUS team has no clue about the force they were able to apply on the hammer.

  • Dave says:

    @ Ian Stirling
    You are right that is the statement attributed to the scientist but the article then goes straight on to dusty comet covering hard ice.
    It's hardly surprising that the blog has exploded today, just look at the title, it bears no resemblance to the picture we see below phillae. It not therefore surprising that people are now questioning all the instruments. Its a shame that what little factual statements there are, are caught up in this way. From todays blog it looks like it could damage credibility

  • ptr says:

    Wow, observations directly from a comet surface! I find this very exiting, can't wait for more!

    The problem with the rock theory would be that the comet'd have to have a much greater mass, or be hollow like an eggshell (as I see it - I'm not an expert). Plus I think if you look at a glacier e.g., ice can look very much like rock, especially when it's dark and mixed with other things. Really can't judge this from looking at a photo.
    But you never know ...

    esa are doing amazing, groundbreaking science here.

    BTW DLR also covers the MUPUS results with a little more detail here:

  • Prof Harvey Rutt says:

    A question to the 'it's the solar wind that machines it' community.

    It's a rather simple calculation to show that at 1AU the power density in the solar wind is around 0.000024W/cm2. That is about 24uW/cm^2
    For comparison, the optical power density is around 0.13W/cm2., nearly 10,000 times higher.
    I have some difficulty understanding how this minute power density is supposed to do anything much.
    Could you explain please; preferably with some *numbers*.

  • Prof Harvey Rutt says:

    actually even more interesting if you consider the current; around 50pA/cm^2., or 0.00000000005a/cm^2.
    Again, for comparison, by electric kettle takes around 10A.
    As it happens, I regularly use an Electric Discharge Machining device to make odd shaped things in difficult materials. It's difficult to do an honest comparison, but the average of the pulsed current density is many, many order of magnitude greater than 50pA/cm^2

    • originalJohn says:

      You keep on about this Rutt because your deductions are based on a naively simplistic model. The heliospheric current flow is far from uniform. Ion current streams are naturally influenced by mutual attraction between plasma filaments, ion acceleration in double layers and magnetic pinch effects. These can result in local increases in current density of many orders of magnitude which could easily account for the observed discharge activity at the surface of this comet nucleus.

      Plasma sputtering of silicate rock is not a communal dream Rutt whereas your fantasy ice sublimation is.

      • Prof Harvey Rutt says:

        The plasma round 67P is extremely tenuous and it does not have a magnetic field strong enough to do anything to ~500keV protons. You just throw words about in an entirely meaningless way.
        If any such thing were occurring it would be blindingly obvious in innumerable ways, spectroscopically, from the plasma measurements, radio noise etc etc. It demonstrably is not.
        Proton sputtering occurs; and its many, many orders of magnitude too weak to explain the *tons of water a second* measured from Kuiper back in 1986 from Halley.
        No one has yet told me why our moon isn't producing vast amounts of water, on the same scale as that seen from comets; it's currently far closer to the sun than 67P. Yes it probably does produce *tiny* amounts of course.

      • THOMAS says:


        Totally agree.

        The problem is that standard theorists (AKA pure mathematicians) always demand numbers to make their equations work so as to be able to stay in their comfort zone. And if the numbers don't work out right, they simply invent new constants, variables or unknowns to make sure their equations do work. It's a bit like playing chess against an opponent who's allowed to change the rules of the game whenever he finds himself in a losing position so as to be sure of wining in the end. But so what, the games the theorists play bear as much relation to the real world as does a game of chess.

        We Urgently need to back-track and once again acknowledge the absolute priority of pattern recognition in actual observations and thus restore the natural sciences as being the true foundation of real scientific method. And the observations being provided by the Rosetta mission will ultimately be seen as a complete "game-changer" in comet science, as Rosetta mission scientist, Matt Taylor, recently stated.

        Meanwhile, the complex workings of electromagnetic phenomena in space, which standard theorists are not trained to understand, are way outside their comfort zone. Small wonder, then, that they desperately cling to their outdated model.

        • Marco says:

          Thomas - I'm just going to say that the numbers don't lie - People can lie, can see patterns when there aren't any, believe the impossible, and make huge errors of judgement. Engineers have a background in the "numerical" sciences and they rely on the "laws" of gravity and electromagnetism, in the same numerical sense that Prof Harvey is promoting. The "exceptionalism" that EU is promoting saying that electromagnetic phenomena in space breaks all the same "laws" machining comets and breaking rock off planets, making a solid rock appear UN-dense etc. appears not only non-numerical, but also non-scientific. The question is, to what degree, and who, is making a misjudgement on the evidence given?

          • THOMAS says:

            Nobody is saying that numbers “lie”, Marco. We all know that 2+2=4. This result is required by the ages-old internal logic of arithmetics and nobody disputes it. But it’s only an internal logic.

            As regards the figure of “40% the density of water”, it’s more a matter of how you define “TRUTH” (rather than “lies”) in the much wider context than that of simple maths.

            And no "exceptionalism" whatever is claimed by EU advocates, quite the contrary: the Electric Universe theory is, by definition, HOLISTIC, since the electric force has been shown in laboratory conditions to be scalable to tens of orders of magnitude. It can thus account for the fundamental workings of everything from the almost-infinitely small to the almost-infinitely large (including how the cells of all living organisms work), via the totally basic +/- electric charge principle.

            As for “believing the impossible”, I stopped doing that around 15 years ago when, after decades as a naively faithful mainstreamer, I finally woke up to the fact that standard cosmological theory required us to “believe six impossible things before breakfast” (like the White Queen proudly manages to do in “Alice Through the Looking Glass”): e.g. 1/“the Big Bang”, 2/“inflation”, 3/“black holes”, 4/“dark matter”, 5/“dark energy”, 6/“neutron stars” (amongst many others). It sometimes takes you to have grown-up kids to finally stop believing in these sorts of fairy-tales. (Though I still fervently believe in others and above all in Hans Christian Andersen’s magnificently prophetic tale “The Emperor’s New Clothes”, which says it all:

            The announced figure for 67P of "40% the density of water" is, by definition, not a “lie” since it has allowed the Rosetta and Philae engineers to perform the extraordinary feats of navigation which we have witnessed over the past weeks and months.

            But it represents no ABSOLUTE truth because it takes absolutely no account of the electromagnetic force which is demonstrably an essential part of what we call "gravity".

            It is all a question of the RELATIVE weighting, in the calculations, of intrinsic mass on the one hand and, on the other hand, the force of induced electromagnetic repulsion (or attraction) due to charge imbalance. The anomalies admitted but not explained by standard theory which are observed in the behaviour of space probes (including Rosetta itself) during planetary flybys are perfectly real but are extremely small, given the overwhelming preponderance of the mass of the planets concerned (= "gravity") over the electromagnetic force which these planets also necessarily exert on nearby passing objects and which is no doubt the source of the observed anomalies.

            It is a totally different kettle of fish in the case of the vanishingly small intrinsic mass of objects (relative to that of the rocky planets) such as comets. In their vicinity, the preponderance of the electromagnetic force evident in the observed, ongoing electrical (EDM) machining processes (AKA “outgassing” in the standard model) on the surface is MAJOR compared with the intrinsic mass. Hence the clearly anomalous "40% the density of water" figure.

            This same object, Comet 67P, if somehow brought back to Earth and then somehow gently lowered through Earth’s magnetosphere without causing a cataclysmic electrical discharge in the process would, in an induced state of electromagnetic equilibrium with Earth, have a measured density of around 2.6 times that of water (i.e. the average density of most types of metamorphic rock) and would immediately plunge to the bottom of any ocean.

            Once the long overdue CONSERT radar findings are finally published and Comet 67P is eventually acknowledged by mission scientists to be entirely made of rock (with all the organic compounds which rock also contains down here on Earth), the totally RELATIVE value of the "40% the density of water" figure will hence also be established once and for all and we shall at long last be able to move on and get along with replacing mathematically driven “gravity-only” myths by the observation-driven models which include the phenomenon of electromagnetism as part of the “equation”. The natural sciences will thus at last regain the place they lost to Einstein and his followers nearly a century ago.

            This mission will not just be a simple “game-changer” as Matt Taylor has already announced. It will truly be the Rosetta stone of early 21st century cosmology, though no at all in the way that was originally meant....

          • Marco says:

            Hi Thomas. I have read it, and I insist it is you who is making a misjudgement on the evidence given in this case. The relationship between mass, density, gravity, acceleration, and the particles that make up matter is extremely well scalable, highly accurate, not modulated by any particular electrical property and experimentally verified at all scales up to a planet.
            Adding a convenient impossibility that an electrical property can be an aspect of a gravitational property is an extreme form of what dark matter and dark energy represent as similar inventions to make a theory fit with observations where the numbers don't add up otherwise.
            Who's to say that the electrical properties won't completely muck up the CONSERT data and give the impression of a snow drift? If you don't take the mass/density at face value, why would you accept other data as representative of reality?

          • THOMAS says:

            Thanks for responding Marco.

            You say “The relationship between mass, density, gravity, acceleration, and the particles that make up matter is extremely well scalable, highly accurate, not modulated by any particular electrical property and experimentally verified at all scales up to a planet.”

            I see no problem in broadly agreeing with your statement. I would simply make the not-so-minor proviso that the as yet unexplained “flyby anomalies” undeniably observed in several recent gravity-assist flybys (including Rosetta’s own Earth flyby in March 2005) tend to rather mitigate what you claim as having been “experimentally verified at all scales up to a planet”.

            These unexplained anomalies logically introduce a serious doubt as to the validity of the “experimental verification” you refer to. If there is indeed a heretofore unacknowledged electromagnetic component in the force of gravity, which “modulates” the apparent mass (hence measured density) of the object, then in the case of a planet flyby it would necessarily be infinitesimal (but apparently observable nevertheless…), given that the mass of the planet is clearly overwhelming with respect to the possible electromagnetic attractive/repulsive force it may exert on the spacecraft.

            In the case of the unique objects which we call “comets”, on the other hand, which are identified as being such precisely by virtue of their coma-producing “activity”, the EU model contends that the observed activity, far from being a simple form of thermo-kinetic “outgassing” as in the standard model, is driven by the electromagnetic relationship which a largish lump of electrically charged rock increasingly entertains with the wider environment of the “solar wind” as it speeds towards (or away from) the Sun. The mass/electromagnetic force relationship will be totally different. Proportionally, the electromagnetic component being exerted on a spacecraft will necessarily be very significantly larger in relation to the simple unmodulated “mass” component than is the case during a simple planet flyby.

            This hypothesis has not, of course, yet been proved empirically. I believe it will be finally established if and when the CONSERT data demonstrate that the core is composed of rock through and through, as the surface appearance suggests. The “40% density of water” figure will thus be shown to be a figure which “works” in terms of its usefulness in enabling the correct calculation of Rosetta’s and Philae’s flight dynamics, but which is underestimated by a factor of five or six in terms of the comet’s absolute, “unmodulated” density.

            If I may take a final analogy from the natural sciences to illustrate how little we as yet really know about the extraordinary workings of natural forces in extreme environments: as you probably know, it came as a huge surprise to marine biologists over 30 years ago to discover that vast colonies of animal and bacterial life-forms (most famously the giant tube-worms: exist in symbiosis around hot (400°C!) vents spewing out supposedly toxic substances several miles deep in the Pacific Ocean. If we hadn’t been there to photograph them for ourselves, the very idea would have been dismissed out of hand as being totally absurd. (Incidentally, the team that first imaged these life-forms in 1977 were actually *geologists*, not biologists, who were merely seeking to prove the existence of hydrothermal vents on the ocean floor: the discovery of not only the vents but also the super-mega-bonus of tube-worms et al. was thus one of the most famous examples ever of scientific serendipity. It totally changed our perception of the limits to possible life-forms).

            Similarly, this is the first time we have been able to study in such depth the extreme environment of a comet nucleus. I am convinced that it will reveal the same sort of serendipitous surprises and be the “game-changer” ESA Mission Scientist Matt Taylor has already announced. Starting with the extremely solid composition of the core and the necessary resulting re-appraisal of the “40% density of water” figure.

          • Marco says:

            I see no hope for EU at all with a continuing claim of contiguous gap free solid rock interior of comets. Also that "emissions" from comets originate from the surface(phenomena) rather than below. These are fantastical claims with no evidence whatsoever, and are not even at the core of what EU is about. They stem from a belief that what is at the "neck" is representative of the "interior" of the comet, and thus solid inside and out including neck. This, from Rosetta data, is exactly the assumption of the standard model that is MOST challenged. From the Rosetta data, it is *physically impossible* for the interior to be solid rock or solid ice.

          • THOMAS says:

            Hi, Marco. You say "it is *physically* impossible for the interior to be solid rock or solid ice."

            What you mean is that it is *theoretically* impossible for the interior to be solid rock or solid ice (and I would add, "or liquid H20"...), on the (sole) basis of the "40% of the density of water" figure.

            You've presumably seen the latest extraordinary NAVCAM image posted this afternoon: Look at the enhanced version in particular.How can anyone still seriously be claiming that this object is mainly hollow, as the "40% of the density of water" figure would require?

          • Marco says:

            I have no issue with it being partly hollow. As I've said, I have a problem with it being called rock. Crude oil, or a mix of hydrocarbons, will have a density lower than 1, be as hard as ice at these temperatures and be structurally sound. However, it would also be pliable enough to stretch. Being microgravity, it is easy to "design" a structure that would easily hold these masses together and be lightweight, It is just hard to imagine how it would get there "naturally". Well, nature is strange and complex, and comets doubly so.
            Maybe comet splitting events are gradual, and we are seeing it part way through the process.

  • Prof Harvey Rutt says:

    For all the 'it's not degassing water, all they see is OH and that's solar wind/silicates' people.

    Several of us have already pointed out that there are not enough protons by many orders of magnitude.

    MIRO on Rosetta explicitly and unambiguously detects H2(16)O2 and can detect (17) and (18). It detects a pure rotational transition, for (16) at 556936MHz and can measure, and has measured, lines shapes and shifts giving pressure and Doppler data. It is absolutely calibrated (and recalibrate a itself regularly) enabling quantitative flow field modelling. It can see a column density down to 10^13.

    However it's been known unambiguously for decades that comets do produce vast amounts of neutral H2O. This was done using infrared bands, a different method. See the reference below, where its producing vast amounts of it.

    How does 'solid rock' manage this?

    Science. 1986 Jun 20;232(4757):1523-8.
    Detection of Water Vapor in Halley's Comet.
    Mumma MJ, Weaver HA, Larson HP, Davis DS, Williams M.
    Gaseous, neutral H(2)O was detected in the coma of comet Halley on 22.1 and 24.1 December 1985 Universal Time. Nine spectral lines of thev(3) band (2.65 micrometers) were found by means of a Fourier transform spectrometer (lambda/triangle uplambda approximately 10(5)) on the NASA-Kuiper Airborne Observatory. The water production rate was approximately 6 x 10(28) molecules per second on 22.1 December and 1.7 x 10(29) molecules per second on 24.1 December UT. The numbers of spectral lines and their intensities are in accord with nonthermal-equilibrium cometary models. Rotational populations are derived from the observed spectral line intensities and excitation conditions are discussed. The ortho-para ratio was found to be 2.66+/-0.13, corresponding to a nuclear-spin temperature of 32 K (+5 K, -2 K), possibly indicating that the observed water vapor originated from a low-temperature ice.

  • Prof Harvey Rutt says:

    Since only about two other people bother with numbers, FYI The measured 1.7*10^29 molecules (yes, molecules, that's what they measured, not hydroxyl) amounts to some 5400kg/second.
    Some going for a lump of rock.

  • Kamal Lodaya says:

    What physics happens when we bake a thick crust pizza, or when we toast bread, or when we make a crisp chapati? Why does the thicker material assemble on the surface? Repeated perihelia might be thought of as applying such a process to the outside of the comet.

    • Jacob nielsen says:

      Where's the cheese? I'd go for chocolate souffle! But I think you're right.

    • Prof Harvey Rutt says:

      Well thick crust pizzas don't ablate much, but comets do. As it approaches the sun, volatile materials such as ice ablate (sublime, (evaporate) mainly.) rock does not. So it's utterly unsurprising the surface would be 'enriched' in rock compared to the interior.
      Your intuition, 'what things look like', is completely useless. This is a very low gravity, high vacuum environment, exposed to hard UV and high energy particles. Nothing at all like earth and completely different processes operate. All those saying 'it's obviously.....(anything)' from its visual appearance are deluding themselves. We simply have no experience on which to make that judgement.
      But I like the thought of a cometary pizza:-)

    • Kamal Lodaya says:

      Harvey: Agree with you. But why has "dirty snowball" stuck? I would say because it jells with some physical intuition which people have. Trying to find good metaphors which people understand. Which one will turn out to be correct we have to wait and see.

      • Harvey Rutt says:

        'Dirty snowball' is just a simple analogy people can visualise. I dont thing anything means it anything like literally.
        Some variant of it seems broadly consistent with the observations.
        Sold rock models clearly are not; they can't account for the water, & lead to pretty crazy internal structure, maybe 80% open space.
        Sold ice models clearly aren't consistent with the data either; because its black & we don't see ice & the density is too low; but at least its only 50% 'porous' (on whatever scale.)

        Any statement thats starts 'its obviously xxxxxxx' basically is likely to be wrong. This environment is so alien in the processes forming it that terrestrial intuition is far more likely to misslead than to inform.

      • Kamal Lodaya says:

        The analogy sticks because it works for very many people, even those like me who have never seen a snowball in their lives. As you point out people are also clear that this is a jocular reference, no one expects to find an actual snowball 4 km in size out in space.

        Later in this blog you argue against theories which make sense for a few people, which they are convinced about, and which they hope to convince others reading this blog. Unfortunately that does not go any way to establishing the theory, since this is just a forum for discussion and not for serious review.

  • frankebe says:

    Just a quick aside for all those who cannot tolerate alternate theories. From today's (11/21/14) Spacewheather site (

    "Although sprites have been seen for at least a century, most scientists did not believe they existed until after 1989 when sprites were photographed by cameras onboard the space shuttle. Now "sprite chasers" regularly photograph the upward bolts from their own homes..."

    Wasn't there a time when scientists refused to believe that rocks fell from the sky? What crackpots would talk such nonsense, right? ...Hmmmm...

    How about let's forget the ad hominem attacks and wait for more data—and analyze what comes in objectively.

    Wasn't it Paul Samuelson (Nobel Prize in economics) who said something like, "when events change, I change my mind. What do you do?"

    Well, what are we going to do? I propose, let's be scientific, not dogmatic. No matter what happens now, it's exciting!

    • Harvey Rutt says:

      There is a rather good history of 'Sprite' observations here:
      Could we have some *evidence* 'most scientists did not believe they existed' please? I wonder how that fact was ascertained? I wouldnt be surprised if there was some school of thought that said they didnt; that's scientific debate; but the *data* proves who is right.
      The modern ability for amateurs to photograph them has more to do with the development of sensitive electronic imaging than anything. Lots of amateurs now take deep space images for the same reason.
      Most scientists (most, not quite all, see my other post) do exactly that; change their theory & model to fit the data.
      'Dogma' usually gets short shrift IM glad to say.

  • Dave says:

    Exactly Frankebe, who would of thought an economist could make so much sense

  • Jacob nielsen says:


    • Jacob nielsen says:

      I ment the pizza, but the comment missed it's goal.

    • Kamal Lodaya says:

      Burnt toast?

      • Jacob Nielsen says:

        no, because toast is porous on the outside. When combining all the pieces of evidence: Density, overall structure, color, temperature, known orbit(s), known chemistry + recently the likely hard surface, we get something like a frozen creme brulee. (or a well done pizza). By the way none of this is in any contradiction with what was known previously, that is: before Rosetta. It is all added detail... unless taken literally 🙂

        my personal status - as if anyone cared 🙂 :
        [I find it possible that all of this exists on 67p: (silicate) rocks, small, large, dust. cryorock, dense, porous, extremely porous,radiation sintered surface layers consisting of: ices, silicates, organics, sulfurous, hard organic sulfur-crosslinked material ("rubber") soft organic "fatty" pools (tar), patches of "destilled" (purified to some extend) CO2, H2O, methane etc. I believe it is likely that must of the surface, the "chin" and "valley"-area are dry regarding most volatiles.]

  • Prof Harvey Rutt says:

    I have nothing 'invested in' the so called dirty snowball theory whatever. I look for an explanation consistent with the measurements and known physics. Quantitatively consistent.
    Right now the only real discrepancy seems to be the surface temperature. That's a bit odd, but probably explicable in terms of the spectral variation of the emissivity of the surface, and the internal structure. We don't have any good data. But pretty much everything else is entirely consistent with a 'porous' mix of ice and rock, surface rock 'enriched' by successive ablation, and darkened by hard UV etc exposure.
    The 'inconvenient' density figure is challenged with no evidence whatever. ESA have navigated to the comet, and round the comet, with superb accuracy. Yet it seems they've achieved all this using equations based on entirely the wrong mechanism. Is that credible?
    There is no shred of evidence supporting these 'electrical' theories at all, and a great deal that is totally inconsistent with it. Where are the spectral emissions, evidence in images, radio emissions etc?
    Many of the claims made are just factually wrong. It's been repeatedly said measurements are always OH ions. This is simply not true. There are multiple direct measurements of neutral water vapour by at least two different techniques,mating back to at least 1986.
    It amuses me, on the main protagonists web site, to see a picture of the surface of an EDM item compared to 67P.
    The structures are 20um across, on a metal, and EDM is done *under oil*, I know, I use it. To compare this to structures hundreds of metres across, formed on an insulator, in vacuum, beggars belief. You cannot EDM insulators, I wish you could, it would be useful to me. Similarly a grain of hematite is compared; no scale, but it's probably mm at most, formed in a high pressure environment, and one of who knows how many shapes. Again the comparison is ludicrous.

    If evidence appears that actually does challenge the 'dirty snowball' theory I'll chuck it out in a second, and be happy to do so. Something new is always fun. But right now all the evidence, thermal anomaly glitch aside, is that's what it is. A fascinating 'dirty snowball'.

    • Marco says:

      Hi Prof - I agree mostly with this assessment; however, I perceive a dismissal of (for one) the surface temperature issue with the same aplomb as the aforementioned dismissal of the density issue of EU. The more I read about the scientific details and measurements both from Philae and remotely by Rosetta, the less your spectral variation of emissivity or other "simple" explanations make any sense at all. And to say that other things such as the shape and features of C-P and other comets are neither here nor there with regards to dirty snowball theory is again dismissal with a hand waving enough to make an EU proponent proud.

      • Prof Harvey Rutt says:

        I certainly do not dismiss the temperature discepancy; that's why I mentioned it. But it doesn't look like something that would require anything too exotic or improbable to explain. However, in the end, it has to be explained in a self consistent way with the rest of the data.
        The shape, certainly, is still a matter of debate. Contact binary, result of ablation, we don't know.

        The EU 'theory' however is no such thing. It never, as far as I can see, makes any quantitative predictions at all. It takes mechanisms that do exist at one scale, and happily assumes they still work at scales many, many orders of magnitude different, in completely different circumstances. The comparison of 20um EDM pits generated by pulsed currents, under oil, on a metal, to 67P is a joke. Any inconvenient bit of data is just vehemently attacked, such as the density. It's logically completely inconsistent; we navigate to 67P, deliver Philae with stunning accuracy - using, apparently, physics that is completely wrong.
        I have absolutely no reason whatever to support one model over another. There are plenty of problems with the detail, plenty of surprises, much to learn. But broadly, what we see is consistent with a 'dirty snowball', inconsistent with a lump of rock, and provides no support at all for 'EU'.

        • Marco says:

          Hi Prof, As scientists, we DO have a reason to support one model over another - Parsimony. More specifically, Occam's razor implies a shift in the burden of proof. Although it is an unacknowledged shift, a lot of aspects and assumptions of the Whipple model are protected from the burden of proof. take the existence of water ice. On the moon, we (still) haven't proven beyond reasonable doubt the existence of water in the shaded polar regions as there are still alternative explanations to sift through with further probes. While with comets, the same remote, and now in situ observations have found no comparable detections of ice, yet ice is still proclaimed confidently.
          As independent observers, we are obliged to not spend our time debunking obvious myths, but putting new ideas and perhaps making suggestions outside of parsimony to get all the disparate results together.

          • Harvey Rutt says:

            Most working scientists would regard Occam's razor/'Parsimony' as a very weak way to decide an outcome.
            It lasts just as long as there is no data inconsistent with the explanation favoured by 'the razor'.
            I dont really think it shifts the burdon of proof, though I see your point. Most will have strongly in mind the fact that there were two or more viable theories we couldnt decide between; & be only too pleased to have an evidentially based way to decide it.
            Indeed many would *seek* a way to decide it.

            Water on the moon is cleatly still an uproven hypothesis as far as I'm aware. I think models support the possibility, but till we see it, its a hypothesis.

            But comets degas vast amounts of water, & contrary to assertions here, there are quantitative measurements of neutral H2O egassing rates going back to 1986. It has to come from somewhere, in Halley's case some 5000kg/second of it. Given that & the low density & temperature, ice seems a pretty good bet,

          • Marco says:

            Prof, with the moon, I remember the Clementine mission was going to decide conclusively where previous probes didn't. The detection was as it was expected to be for water ice on the moon. I thought - case closed. But it is like the "false positive" medical test. If a disease (or water on the moon) is thought to be a one in a biillion thing, positive test results can always be regarded as inconclusive, no matter the sophistication. Equally on believed "false negatives" (about ice) on comets. If it is believed 99.99% certain to be ice on there, no negative result will be "believed". Thus our preconceived beliefs become the science of the gaps. Every limitation of every test gets multiplied by how improbable we believe the unexpected result to be. This is parsimony at work, pure and simple, at the individual experiment level.

      • THOMAS says:

        @ Marco "I perceive a dismissal of (for one) the surface temperature issue with the same aplomb as the aforementioned dismissal of the density issue of EU."

        Marco, Electric Universe proponents do NOT "dismiss" what you call the "density issue", with or without aplomb. They positively ACCOUNT for it by an electromagnetic mechanism whose existence mainstreamers consistently refuse even to acknowledge. (See my post above).

        You are absolutely right, on the other hand, to point out that the same proponents of standard theory who invariably require their gainsayers to provide figures in support of alternative theories curiously have no such demands on themselves whenever the facts and figures are shown to falsify their own theory (yet again, and again!).

        They of course have nothing whatever to say, for example, about the hugely inverse temperature curves (inverted compared with the expectations of standard theory) observed between the chronosphere and the corona of the Sun: they presumably don't like the observed figures and they certainly don't have the foggiest idea of how to explain them. The policy is simply to ignore “discordant” observations and figures (whether on the Sun or on Comet 67P) and hope they will just go away.

        Though we may also soon be reading peer-reviewed papers which aim to prove that the observed "shape and features" of 67P were actually predicted by standard theory. In the world of pure theorists, anything is possible.

        Nuff said.

        • Marco says:

          Thomas. Like I said - numbers don't lie, and people are easily convinced by mechanisms that just don't add up. That goes for the mechanism to "account" for the low density calculation. If it "accounts" for it- show me the numbers. It also goes for surface and close to surface ice, of course.

          As well as CONSERT data, perihelion loss of mass/volume and how that transforms the comet will help in understanding and predicting how comets work. Neck stretch? Or neck ablation? Other kinds of mass loss?
          Collapse of features due to mass loss below surface? Or direct surface changes?
          At the moment I'm leaning towards a "cement" kind of surface rather than rock. Considerable voids below surface in the form of "pipes" in a kind of bronchioles network, also chambers. The outer layer holding quite firm as a kind of exoskeleton. Of course, considerable water melt areas inside. I am quite confident that the neck is stretching rather than ablating. Given this complexity, I would predict CONSERT data to be inconclusive as they may not capture the complexity through lack of resolution. Long term Rosetta data would confirm or contradict some of this.

          • THOMAS says:


            Totally stratified cement, in that case?

            In my above post, I referred to an earlier, much longer one which I submitted over 36 hours ago on 23/11/2014 at 23:11 and which is still "awaiting moderation". I've just asked the moderators to finally publish it - I'm sure I didn't say anything rude in it...

            If they do publish it, read it because without it, my above post loses much of its meaning. (In particular, I again in that earlier post address the "40% density of water" issue, which the defenders of the standard theory are still clinging to as their remaining hope despite all the nay-saying ocular evidence, and which you understandably give credence to yourself, as supporting your panspermia model).

          • Marco says:

            Hi Thomas, not stratified - these are *Stretch Marks*. I just thought of an easy way to test which! Stratifications will be in parallel *Planes* while stretch marks on the neck at least will be in parallel *Helical/spiral* segments. Planes viewed from opposite directions will appear diagonal in mirror-opposite direction, while helical segments will appear diagonal in the same direction.
            Data should be convincing no?

          • THOMAS says:

            Marco, what sort of naturally occurring material can be "stretched" in this sort of environment and by what physical process?

            The stratification can be see in every image, in every cliff-face, in every jagged outcrop and even in certain large free-standing boulders. Hardly "stretch marks".

          • Marco says:

            I was thinking frozen/amorphous crude oil. At these temperatures it would look like coal ( or black rock, if you will)
            "Stretching" would occur due to a complex combination of centrifugal force from spinning, tidal force from both the Sun and Jupiter, as in certain alignments tidal forces would be greater than gravity at certain points in its rotation each day. Also other energy transformations such as chemical energy, even nuclear energy and of course.... Electromagnetic energy as well...

        • Harvey Rutt says:

          I'm fascinated to know how ESA navigate Rosetaa with exquisite precision to and around the comet, when there is a force completely unknown to their models which totally falisifies the mass of the comet.
          Its not only 67P of course, but a panolpy of other such spacecraft navigation & orbital calculations. They work, supremely well.
          There is of course the very small 'Voyager discrepancy' (the concensus is its *probably* not 'fundamental in nature, but people were still looking last time I checked), & I agree entirely 'dark energy' & 'dark matter' seem very contrived & unsatifying, but are irrelevant at this scale.

          On this scale, gravitational models *demonstrably* work supremely well; how is that poissible if a force which could grossly falsify the mass is operating?

  • Tom Barnaby says:

    This is a gem:

    "“If we compare the data with laboratory measurements, we think that the probe encountered a hard surface with strength comparable to that of solid ice,” says Tilman Spohn, principal investigator for MUPUS."

    Well, ice is a solid because it's the solid state of water. Since the Rosetta team thinks that comets are dirty snowballs, didn't they design their drills for ice? In which case, their drills should have worked just as in pre-flight tests on, yes you guessed it, ice!

    The Rosetta team seems to be avoiding a statement of the obvious - 67P is rock, with rocky detritus.

  • Dave says:

    Copernicus, did the maths and it was a revelation until Newton did the maths and it was astonishing, We still use this all over the place, as an engineer, i couldnt do without it. But as we got to the 20th century we discovered that Newtonion was not quite right. relativity held sway, even then Eistien could not make it fit all observations even on the large scale, hence he could not decide whether his constant was required or not.
    If Relativity did not quite work, quantum theory sure streched our imaginations even further, and that did not quite work either.
    To make things work, we now have dark matter and dark energy, black holes and I think something like dark curved space.
    All of these are supported by numbers, but we are asked to believe that we can only see less than 3% of the universe! Does it really seem to you that the NUMBERS have given us the right answers, just because we can use them to model some of the reality we can see?

    What should come first, theory or the numbers?

  • Edward cox says:

    A reminder everyone the mash of the spacecraft relative to the strengths of the drill is exceedingly low and as a consequence of the torque of the drill so unless a spacecraft were anchored to the surface The action of the drill or penetrator would be sufficient to cause a spacecraft to lift away each time the drill was used.

  • Marco says:

    I think a citizen scientist detective has found Philae in the latest NavCam picture before ESA scientists could :-O.

    • THOMAS says:

      Yeah, I already checked that out and the evidence looks pretty convincing.

      But what makes you think that this was found "before ESA scientists could"?

      I've been thinking for several days tha the Rosetta scientists must necessarily have already located Philae via a combination of the images and the CONSERT data.

      They've just been sitting on the information, as they are sitting on the vast majority of the other information. It is a policy which was announced well in advance, so why should we be surprised or complain about it?

      They'll perhaps have a little explaining away to do and look a little silly, though, if the simple "citizen scientist detective" you refer to is correct in his detective work and has upstaged them in divulging the information they already had....

      • Marco says:

        Well, Thomas, the silence from the Rosetta team has been deafening since they published the spots they have been looking. I take the silence as them being speechless at being upstaged. Like you, I think they may be "not believing" the data from CONSERT. If an experiment finds what they believe to be impossible, they will insist on the possibility of instrumental failure or calibration error. Although what I think is in the interior of the comet is completely different from what you think is; neither is one of the possibilities they have simulated or postulated....I think this is very sad, as preconceived ideas should not control the interpretation of data. I don't agree with the prof about these scientists. if the data says that the model is very wrong, they will doubt the data- not think of a new model. At the margins, they may modify the model in that the words they were using will mean something different - eg. Porous, rubble pile, etc.

        • Jacob nielsen says:

          If you are working with a very well established scientific principle / figure: at first doubt you setup etc. If working on the white map areas: doubt everything, most of all your own mind & senses. Right?

          • Marco says:

            Yes. But at what stage do you stop assuming the setup etc. is wrong? Anyhow we are not talking about fundamental scientific laws - we are talking about what is inside the comet. There should be no preconceived ideas other than the net density. Everything else should be given an equal starting probability.

          • Marco says:

            I might like to add that it is a copout. Despite protestations by scientists to the contrary, the burden of proof of surface or near surface ice has been *REMOVED*. Time and time again tests that would be considered a conclusion of dry on the moon, are consistently doubted as conclusive on C-G. The burden of proof has been laid squarely as "prove that there is definitively no ice on the surface or subsurface" That is a much higher bar than reasonable, as there are no contradictions with any laws of ohysics if there is no water on the surface or near subsurface.

        • THOMAS says:

          I fully share your fears, Marco.

  • Harvey Rutt says:

    A number of people here seem to have no concept at all of how real science actually works, in two respects.

    Firstly the relationship to mathematics. This has very little to do with 'pure mathematics'. Its applied math, & it is essentially the 'language of' the physical sciences. To claim science should get away from the math is like saying French Literature should abandon the French language; the two are inseparable. You can say pretty much anything; but its the numbers that tell you if you are right or not. The models have to be verified by experiment; 'the data is king'. The models must be 'falsifyable', make concrete, testable, quantitative predictions. To talk of science 'getting away from the maths' or whatever the phrase was is, quite simply, to *stop doing science*.

    The other aspect is the reaction of *most* (not quite all) scientists to data that does not fit their pet theory. I've been around them for my entire career, & *most*, will, probably after looking for some sort of cross check, shrug their shoulders & start looking for a new theory that *does* fiit. In fact most of us enjoy such a situation; its fun, interesting, I always tell my PhD students that the most interesting data is often the bit that *dooesnt* do what you expected; never reject it, explore it.

    Now there are a few who get wedded to some theory. My personal experience is they are a small minority. They only see things which agree with their model, blind themselves to what doesnt; yes, I've seen that a handful of times. Its unconscious self deception, usually in a small 'clique' or single lab. There is an even smaller minority where it is deliberate fraud; never encountered it for sure, but was suspicious once.

    But there is a *srong* corrective mechanism. Whilst a small group gets like that, or comits fraud, the wider community tends pretty quickly to be 'on it'. If you have the right model, & they are sticking like grim death to the wrong one, you can get a good career jump out of that, write some highly cited papers etc etc. OK, you might suffer a spat with a biased referee from that 'in group', it can happen. But you can get past that, in the longer run, 'truth will out'.

    Its clear most, probably all, those espousing the EU model are not working scientists. I do not, from a lifetime's experience of real science, recognise how they seem to think science 'works'.
    This idea of a huge community hanging on like grim death to an impossible model just makes no sense at all. In modern times, small sub sets of people, for limited periods, yes, it can happen. On the scale proposed here, no, it doesnt.

    On top of which you have quantities of scientifically competent people, who can run the numbers, watching from the sidelines. I'm one of them in this case. If there were a gross problem, many of them will cry 'FOUL' too; as I would. And some have enough 'weight to get heard'.

    If anyone is distortng, missrepresenting & ignoring evidence in this its the EU community. And they never, ever provide *numbers*. Many of the processes they mention *do exist*; but are utterly irrelevant on the scales appropriate to this problem.

  • Prof Harvey Rutt says:

    To ask which comes first is a rather chicken and egg question.
    Often we have numbers first, then build a model, and test its predictions. So in some sense the numbers came first.
    Sometimes we have a model which predicts a completely unexpected effect, and we make measurements that confirm that; so in a sense the theory came first.
    I'm not sure it matters much.
    But science rests on *quantitative* predictions which are then tested by measurement.
    When we find a discrepancy, as we did from Newton's model at high enough velocity for example, we look for a better theory.
    That is not remotely what is happening with EU 'theories'. They simply rubbish, without reason or evidence, inconvenient results, and bandy words about - never, ever, numbers - when it is pointed out that a proposed mechanism is orders of magnitude too weak etc. Frequently the comparisons are outrageous, EDM marks to comet craters, grains of haematite to comets. Some statements, often repeated, are simply untrue, such as 'only OH is measured....'
    That's not scientific evolution to a better theory, if accurately described, I'd probably get banned 🙂

    There are certainly aspects of the large scale universe where our understanding is lacking, and aspects of the current theories that seem very unsatisfying. However there is no rule of the Universe that says humans have to find its laws satisfying! Many aspects of modern quantum mechanics (which I use routinely) people find deeply unsatisfying - as Einstein did - but every test we do confirms them. In the end, what matters is does the prediction fit the measurement.

    • Marco says:

      Hi Prof, EU theory, to me is a symptom of a greater ill of science. I find it hard to get a hearing criticising scientific consensus because it is seen as a stalking horse for quasi-religious or religious views. I criticise the consensus of ice, as comet after comet is shown to have large solid cross connected features (features connect to each other and/or the comet) that are also devoid of volatiles. How's this for a number - solid volatiles confirmed on the surface or subsurface by Rosetta or Philae 0. Choose any units you like. Ablation of volatiles from a mixture would leave behind actual dust - not a solid dry crust. I criticise the use of the term "rubble pile" when the solid features are solidly connected to the whole contiguous nucleus. I criticise the use of the word "porous" (unless in the understanding that it just means an unknown structure that has low net density). Although "modified" Whipple model theory might explain away the fact that the original model failed to predict, well, anything that was actually observed, it rings hollow if it still just predicts what was already known via Earth observations. If no scientist has any particular "investment" in modified Whipple theory, why not drop it and say individual details and assumptions are up for grabs- Just not the tried and tested laws of physics.

      • THOMAS says:

        @ Harvey Rutt

        « To claim science should get away from the math is like saying French Literature should abandon the French language; the two are inseparable.”

        No, Prof. Two fallacies in a single sentence of 23 words:

        1/ NOBODY is claiming that “science should get away from the math”, and especially not EU proponents. The NATURAL sciences necessarily use different branches of maths as essential TOOLS, to help to confirm or invalidate a given hypothesis based on actual observation, just as a gardener uses a spade, a fork, a hoe or a trowel, etc. to plant then grow a given vegetable or flower. Without maths, for example, we obviously could never have built up the genome, with all the considerable benefits in the treatment of numerous diseases it has brought us.

        2/ The comparison you then make with the idea that it’s as if we’re saying that “French Literature should abandon the French language” is quite literally invalid and suggests that you are probably more at ease with figures than with literature or logic. “French Literature” necessarily uses the French language as a TOOL, just as English, German Spanish or Italian literature also use the language they are expressed in as TOOLS. (And, as we have just seen, the natural sciences also use maths as a LANGUAGE TOOL to express themselves). The corpus of “French literature”, on the other hand, (like that of all other national literatures), has been built up by people voting with their feet through buying books and going to the theatre (even Molière or Shakespeare, originally). So whereas any banal scientific paper can get through the peer-review process as long as it contains enough maths and doesn’t tread on any illustrious scientific toes, all the unnecessary, pretentious rubbish which seeks to dress itself up as literature just doesn’t get over the very first hurdle of long-term public acceptance.

        You are wrong to think, Prof, with your “argument from authority”, that you are one of the chosen few who know “how real science actually works”.

        I suggest you start reading up about what EU proponents are really saying rather than rejecting their theses out of hand or simply caricaturing them. Perhaps you could begin with the work of the 1970 Nobel Physics Prize winner, Hannes Alfvén, the father of modern plasma physics and take it from there.

        In the meantime, I’d love to hear, for example, about how the standard theory, with all its gravity-only entities, equations and numbers, accounts for the totally unexpected and inexplicable (by standard theory) phenomenon of the inverse temperature curve at and above the surface of the Sun, with the outer corona being several thousand times hotter than the chromosphere below it. The standard model is going from one surprise to another in being totally unable to account even for how our nearest star is driven.

        Not surprising then that it will be equally astonished by the “game-changing” data which is being grudgingly released on the totally unexpected (by standard theory) Comet 67P.

        • Prof Harvey Rutt says:

          Maths is indeed a tool; which I note you never use. But in the end the formulae provide a way to predict the results of observations, the numbers, which tells us whether that model is adequate for the particular circumstances.

          Nobody, certainly not me, claims our current models explain everything. In fact as it happens in some sense the high temperatures in the corona probably *are* caused by what one might describe as an 'electric universe' effect, namely magnetic reconnection, though there is much to understand there.

          Scientific papers gets selected out much like literature. The boring rest unread and uncited, the important, including Alfven's work, live on, re read, cited. So what?

          None of this has any bearing at all on mysterious forces falsifying the mass of 67P. Since you agree that maths is a useful tool, could you apply it to demonstrate what charges the required forces imply, and how they were achieved?

          I won't bother too much with the ad hominem attacks on my literacy, or knowledge of language; 頑張ってください

          • THOMAS says:

            @ Harvey Rutt

            Sincere apologies for any perceived ad hominem attack.

            I no doubt over-reacted to your proposed analogy between science/maths and French literature/French, which I still consider to be invalid, for the reasons given. (I have lived and worked in France for several decades and know quite a lot about literature in general and French literature in particular…).

            I actually find your comments fairly balanced as regards the observational aspects of the question, as in your admission that the EU model might have some bearing on the observed behaviour of the Sun. I simply take issue with your insistence that nothing can be scientifically true if it is not immediately backed up with numbers. How do you reconcile this requirement with the ‘chicken and egg’ dilemma which you point out yourself in your above post: You say “I'm not sure it matters much". I disagree.

            In the world of the natural sciences, there are observations which are sufficient in themselves to totally overturn currently held perceptions and paradigms, without any need whatever for supporting numbers. I have just posted a reply to Marco on this thread ( in which I speak of the human exploration of extreme environments and draw a comparison between the utterly unexpected appearance of 67P and the utterly unexpected and totally serendipitous discovery of large thriving colonies of previously unknown life-forms around hot (400°C!) vents feeding on supposedly toxic substances at a depth of several km on the floor of the Pacific Ocean. The latter observation represented a total paradigm shift in our understanding of the conditions in which life is possible. No need whatever for numbers in these cases (which possible numbers?), the pictures speak for themselves.

            As regards 67P, there is an evident and total contradiction between the utterly robust, solid, rocky appearance of the nucleus as it has constantly been imaged from the beginning back on August 6 and the “40% density of water” figure which has indeed apparently enabled mission scientists to manage the flight dynamics with extreme precision but which would necessarily require the nucleus to be totally hollow beneath a hypothesized “crust” (not even filled with ice or water…). My approach to science (like all natural scientists, and hence like the EU people) is to begin with the real world observations so as to formulate a theory and then to seek to account for any apparently conflicting data, such as the “40% density of water” figure (again, see my post.

            In all humility, could you please translate “頑張ってください" into English for me?

  • Dave says:


    My point really was sometimes observation is much more important than the numders.
    I am sure that sailors new for hundreds of years that the earth was not flat before it was proved.
    They even managed to sail round the world before maths proved that is was round. no maths was required for the proof.

    Also just when we get comfortable with a mathmatical proof we seem to find that it was not quite as good as we thought, observation is important long after the maths is settled.

    Dogma is a killer. whether flawed observation and or measurement, or flawed mathmactical descriptions of our percieved reality.

    The odd temperature of the Comet and the odd density, which does not seem to fit any of the theories at the moment are a good thing. It means every body has to venture outside of the dogma, untill all is explained again.
    Then we can all settle down with a new dogma.

  • Harvey Rutt says:

    Out of interest, what evidence would you cite that 'sailors knew for hiundreds of years the earth was not flat.....'. I cant think of any. It might be true; I could not disprove it; but I cant think of any evidence whatever to support it.

    We are certainly agreed that 'dogma' is a killer. Where we disagree is how much 'dogma' there is in science. Having worked in it rather a long time, I see very little. Some, yes, but the corrective mechanisms i described act to elliminate it pretty well. There are, contrary to common belief, absolutely NO 'scientific laws'. Everything is always up for grabs, valid just as long as the data supports it. Now if you seek to overturn a cornerstone, 'exceptional claims require exceptional evidence' - but if you are right, you'll win. 'Dirty snowballs' are hardly in that league anyway.

    Currently I really dont see anything that overturns views on such a scale. They may falisy some detailed model; but seem quite consistent with a some model based on a 'porous dirty snowball with a crust', and with known physics.
    In contrast EU is more full of holes that 67P seems to be 🙂

    • Dave says:

      I agree with you Harvey.

      apart from the last paragraph, but that could be true if someone can find some ice.

      I guess Columbus was the best evidence that someone thought he could get round the world. There are various other anecdotal, evidence that others thought it was curved (No evidence I know of that they thought they were on a sphere). They could not understand how ships were first sited by the top of the mast.
      I am sure Columbus would not of been first, but he did raise the money and try. Probably at that time you could still get burnt at the stake for an opinion that the earth was spherical, I don't know.
      The dirty snow ball was ok as a laymans desciption based on the information available at the time, I have no issue with that. The focus on it seems to have come because, even if it is not a snowball, it appears as if its not even ice, data from Phillae may tell otherwise if it gets going again.
      So this presents a problem, most of the models proposed on the blog can not get round the absence of ice. This has been apparently true on the handfull of comets we have got close enough to, to have a look at.
      All of the theories discussed on the blog can be shown to have a major flaw in one way or another at the moment.
      Its easy to say there is water in the coma so it must come from the comet, its a statement of the obvious, but that statement does not prove or disprove any of the models. At the moment there is no proof one way or another how that water gets there.

      Hence right now we just have theories, hopefully when we get some more information, there may be some convergence of views.

      Once we have some convergence then the maths will be important because we will be for the first time since Mr Whipple, be able to prove a new theory of comet formation, or at least some of it.

      It may be frustrating for you that none of the theories on the blog can be proved, especially it seems the EU theory, but I have not seen anything at the moment that proves any of the theories shown on this blog.
      We are all in the same boat.

      We need more observation, then the maths.

      Then we can all debunk what ever is left.

  • Harvey Rutt says:

    Over coffee, I thought it would be interesting to see what happens when a 500keV proton his 'a suitable target material', using SRIM, a very widely used program which Monte Carlo simulates ion implanation etc. It has been extensvely validated.
    What target to use..... actually, it won't change things *that* much, but of the easily available list I chose concrete; a concrete comet 🙂 Yes, changing it will change things in detail, but not that much.
    The results of a couple of hours on a 24Gb, Intel Core i7, '12 processor', 3.33GHz machine can be found here:
    (SRIM does not use the '12' processors efficiently. You can download SRIM for free & its easy to use, but like most Monte Carlo codes, it will sweat your machine.)
    The results are interesting. The protons of course have a rather well defined range, of just over 5um. They get very efficiently buried. After 1545 injected protons, *not one* has backscattered, and *no substrate atom has sputtered.*
    If this is the major mechanism - as it might be say on an asteroid perhaps - then eventually, it will sputter down to the buried proton layer, which will have moved forward as the surface retreats. So you will start sputtering out the protons injected long ago.
    But if other processes are erroding the surface, or indeed covering it, the situation will be very different.

    I dont actually draw any particlar conclusions from this; but others might find it interesting, & it might provide some insight into the solar wind interaction. (If anyone really wants me too, I could set another case running in the background & post the results.)

  • Ed Johnson says:

    Congratulations to to the MUPUS scientists for getting some preliminary results posted.
    There are nine (?) other experiments on the lander. Where are these readings? Even if not fully analyzed.

  • THOMAS says:

    My post originally submitted on 23/11/2014 at 23:11 has finally been published in the last couple of hours.

    • Prof Harvey Rutt says:

      For some r a son your other post has no 'reply' button, so placed slightly randomly here.
      頑張ってください,which in kana is がんばってください or in Romaji ' ganbatte kudasai' is a very common Japanese phrase. It comprises the 'Te form' of the verb ganbaru, literally 'to persevere', plus kudasai, a polite version of 'please'. It can be translated in many ways; most literally as 'do your best' or 'soldier on'; here used somewhat ironically, as it can be in Japan. I speak a fair bit of Japanese (though not fluent) and read kana, but I don't know enough kanji to read properly. Haiku and tanka in the original are very different to translations, and mercifully short.
      It also happens that I am fairly fluent in French and have shelves full of French literature, and have read a lot of Portuguese too. Where to put books and classical CDs is a persistent problem in our house.
      So I found the comment rather amusing.

      • THOMAS says:

        Thanks for the explanation; I must say I feared something slightly less mentionable...

        It sounds very similar to the French 'Bon courage' , which can, as you presumably know if you are fluent in French, also be used ironically if the speaker has serious doubts about the venture which the other is engaged upon.

        Speaking of literature and irony, my all-time favourite work of French literature is Diderot’s “Jacques le Fataliste”, in which Jacques’ philosophical catch-phrase “C’est écrit là-haut (sur le Grand Rouleau)” I find particularly apposite in the context of our discussion, in various ironic ways I will leave you to explore. If the book isn’t already crammed onto one of your bookshelves, I urge you to buy it and read it. In addition, for a work published towards the end of the 18th century, I find the delightfully and constantly digressive unfolding of various disparate (and often trivial) narratives, with the narrator regularly haranguing the reader about his disappointed expectations, to be a striking precursor of our modern blogs, including scientific blogs such as this one….

        Coming back to much more mundane matters, my “other post” had no ‘Reply’ button simply because the column-width had become too narrow. You should have posted it as a reply to your own original
        27/11/2014 at 00:21 comment, in which case it would have lined up neatly beneath my post.

        A bientôt....

        • Prof Harvey Rutt says:

          Rather off comets, but yes, 'Bon courage' would be a decent translation of ganbatte (kudasai.)
          I'm might go back to reading more French, but for the moment Japanese occupies available language time. If so I'll try the Diderot. I tend to prefer modern French authors like Modiano, well deserved N prize.
          'A bientot' would be 'mata, ne'.
          (Very colloquial, only to similar age/status person.)
          Sorry don't have accents set up on the iPad.

  • THOMAS says:

    This comment was meant more specifically for Marco (I don't know why it was sent to the bottom of the page).

    But there's also stuff in my heavily postponed post above ( for people like Prof Harvey Rutt who trash everything in the EU approach out of hand for so-called lack of numbers while seeing no problem at all with accepting the mountains of unobserved, unproven and unfalsifiable assumptions which are supposed to underpin the Big Bang theory which the "dirty snowball" model is another impossible part of.

    • Harvey Rutt says:

      So, please remedy the 'so called' lack of numbers.
      It's an A level physics calculation to work out what charges would be needed on Philae & 67P to generate the force you say exists. (Well it's the product of the charges of course that determines the force, we'd need to decide how to distribute them. Equal charge density perhaps?) That leads to a voltage, & requires a charging mechanism.
      To make life simple, we can used the physicists beloved spherical approximation, lets call 67P a 1km radius sphere, and Rosetta maybe a 2m radius sphere. They will show us the ball- park results.
      I have yet to see a number in your posts, can you supply some?

      Red herring arguments re the big bang, dark matter etc are utterly irrelvant to the measurements on 67P.

      • THOMAS says:

        @ Harvey Rutt

        I've answered one of your previous posts above ( It has just been published.

        As regards the required calculation being no more difficult than an 'A level Physics calculation', I don't quite see your point since, to my knowledge, even the most basic principles of plasma physics are not part of the A Level curriculum nor even of most Higher Education astronomy courses. The guardians of the standard theory are ever on the watch-tower….

        If the EU hypothesis is correct, there is no question of "equal charge density": the observed jets are the result of intense, highly *localized* currents impinging on the comet surface in preferential but unpredictable locations and machining matter away via discharge activity into the coma. We presently know as little about the precise origin, location and strength of the discharges as we know about the fundamental mechanisms driving lightning strokes on Earth (despite the fact that we have been observing and studying them, in some fear and trepidation, since the beginning of time). I assume you are not able to forecast where and when the next one is going to strike in your neck of the woods, let alone what voltage will be involved. It is not because we can’t quantify a physical phenomenon as you seem to require that it doesn’t exist.

        The major difference between lightning strokes on Earth and discharge events on the surface of a comet is that terrestrial lightning is manifested in arc-mode and cometary discharge events most often in glow-mode (except when comets “explode” as seems to have happened, for example, to Comet 17P/Holmes in October 2007 when it was suddenly observed to brighten by a factor of around half a million – there’s a number for you!– within just a few hours, out past the orbit of Mars: the cause was presumably a mega-lightning bolt – standard theory has absolutely no explanation for this sort of event). Both types of phenomena are demonstrably the result of an electrical connection with the Sun (though in the case of terrestrial lightning, this is only just beginning to be realized through the observation of electromagnetic phenomena called “Upper-atmospheric lightning” high up in the magnetosphere above areas of everyday lightning discharge which takes the form of “red sprites”, “blue jets” and “elves” as explained here: ).

        Sorry, no numbers, but so what? These observations are “game-changers” for astrophysics (even without numbers) in the same way that back in 1977 the observation of vast colonies of animal and bacterial life-forms (most famously the giant tube-worms: around hot (400°C!) vents spewing out supposedly toxic substances several miles deep in the Pacific Ocean was already a game-changer for our understanding of the limits to possible life-forms. No numbers, just observations…

        • Prof Harvey Rutt says:

          We were not discussing the discharges; we were discussing the force acting on Rosetta which is apparently falsifying the density measurement. The so called discharges are utterly irrelevant. You need a force *that mimics gravity* or ESA could not conceivably navigate near 67P. there is no way whatever some 'discharge jet' can produce a constant, consistently radially directed force which scales as 1/r^2. As usual, no response to the post pointing out that only the electrostatic part of the Lorentz force does that.

          As it happens, I ran a section of my division simulating strikes on aircraft for some years. (The loud bangs weren't very popular.) The voltages, currents and waveforms are very well known. The charge separation mechanism known, but details still to sort. The link to the upper atmosphere phenomena I've not looked into, but not all storms produce them, and storms happen at night. No, exact locations can't be predicted, but I wouldn't stand too close to a lightning conductor in a storm personally.

          But let's think about these supposed, never observed, gargantuan discharges a bit.

          Glow discharges are low current density, low pressure, long Debye length phenomena. They generally *do not* damage the electrode - which is why plasma TVs and neon signs continue to work. Arcs are high pressure, short Debye length discharges, which do damage the electrode typically - EDM in fact. Glows can construct into arcs at the electrode - but -

          But this requires a high current density. You need to feed in the charge from a large area of the body storing the charge; so you need a highly conducting surface. EDM is done on metals, not insulators. Last time I looked lumps of rock were rather good insulators.

          You need some sort of impulsive discharge, or it would be a track, not a round crater. So you need to store the energy and discharge it suddenly to generate craters. But capacitive storage is actually a very poor way to store energy - compare a MJ capacitor bank to a few hundred grams of TNT. On top of which the discharge path would have huge inductance.

          How did it get charged up? The solar wind peaks around 5keV, trifling, though it has minor constituents to hundreds of keV, and tiny ones still higher. Thunderstorms manage MVs. But the solar wind is neutral; it contains electrons too. As soon as something moves significantly positive, crudely put, it will start dragging in electrons, limiting how far it can shift potential (and vice versa.) Sure it can charge a bit; but it has no way to store the TJ or whatever scale it is to dig multi km craters.

          There are lots of lovely problems explaining Holmes etc etc. The EU proposals generate more problems than they answer.

          However, I wouldn't totally rule out some sort of discharge activity in some circumstances. Especially closer in, if hit by a CME, maybe, it could drive some secondary processes. But as the prime power source of most cometary activity, I'll stick to the power supply with umpteen orders of magnitude more power density until there is evidence otherwise; and if there is evidence, I'll happily switch.

          Oh, why wasn't there a big flash bang when Philae touched down?

          "No numbers, so what" - no credibility, that's what.

  • Harvey Rutt says:

    Out of interest, I let SRIM/TRIM run overnight on three cases.
    The results are probably not relevant to Philae where more rapid ablative/redeposition mechanisms probably overwhelm this. But they would apply to asteroids & the moon, to Philae when remote from the sun possibly, & indeed a quick look suggests there are a good few papers about it regarding recovered lunar material.
    This is a continued run, 500keV protons into my concrete comet, 13502 ions, just improves the statistics.
    Interestingly no sputter events, just two 'backscatters'. I think SRIM/TRIM defines 'backscatter' as the incident ion leaving the surface - but its remote from the entry point, you can probably see the two 'backscatter' events below the impact point. Normal incidence 500keV protons are extremely inefficient at sputtering things. A quick look in the literature suggests the 10^-4 to 10^-5 sputter/incident ion range, so none in 13000 odd is unsurprising.
    It occurred to me oblique incidence would be different, & it is. I ran it again but at 80 degrees, very oblique. Now we have 48 'backscatters' in 5000 ions, and 7 oxygen, 2 silicon, three calcium & one magnesium atoms get sputtered, total 13, so a sputter yield of ~0.3% (poor statistics of course.) Small, but far higher than at normal. I suspect, but can't easily check, that the sputter events are actually caused by the backscatter ions exiting the surface.
    What this might lead to is strange looking microstructures caused by angle of incidence variation of sputter yield. Such things certainly happen in the Lab, & it seems are known from lunar samples at a quick glance.
    For no very sensible reason I also ran 'liquid water' (it doesn't provide ice) though quite how one would irradiate liquid water with 500keV protons I'm not sure! Ice would be very similar. Basically again no backscatters or sputter seen at normal incidence. Of course even a few microns of anything on the surface means this would not apply; exposed ice only, which has not been seen on Philae.

    • Harvey Rutt says:

      Sorry that should read 'to 67P when remote from...'

    • Prof Harvey Rutt says:

      In fact these were run at an inappropriate proton energy. I looked up solar wind energies and there was a unit error on the Web site I happened to use. There certainly are 500keV protons in the solar wind and higher energies still, but not many; 5keV is far more typical.
      This will *increase* sputter yields I suspect (but raise further problems re charging and power densities.)
      Amusing that no one picked this up; but numbers and actual calculations don't figure much here.
      I can re run SRIM/TRIM if anyone cares.

  • Prof Harvey Rutt says:

    More red herrings, this time from the deep sea.

    Can we please have a calculation of the charges, voltages and resultant forces on the spacecraft, and a mechanism to achieve them, which are consistent with the orbital mechanics. The force on the spacecraft at 30km won't be much affected by charge distribution; if it won't work for a couple of spherical bodies, no amount of localising it etc will help.

    It's not much more than A level physics. It's not plasma physics, it's electrostatics.

    • THOMAS says:

      Hi, Prof.

      Still not addressing the issue of paradigm-shifting *observations*, Prof? Riftia pachyptila can hardly be called "herrings" whether red or not. Terrestrial lightning strikes, “red sprites”, “blue jets”, “elves” and what happened to Comet 17P/Holmes have nothing to do with the "deep ocean". It would be nice if *you* stopped eluding the challenging questions posed by actual observation.

      Why only "electrostatics" and not "plasma physics"? Because you know much more about electrostatics? It's a natural reaction to want to stay in one's personal comfort zone fenced in by reassuringly solvable equations. But please don't claim it has much to do with correct scientific method, the starting point of which is invariably *observation*. The maths, when required, comes next.

      • Harvey says:

        Thomas, every time you descend to ad hominem attacks you lose further credibility.
        I really can’t be bothered with it; do a little research if you want to confirm my ‘numeracy’.
        As ever, no physics, no formulae, no numbers, just assertions.

        There is a very, very obvious reason I stress the electrostatic force.
        The force from the electrical effects results from the Lorentz equation.
        F=q.(E+v X B)
        The first, ‘electrostatic’ term can be written
        Fes=(Q1.Q2)/(4*Pi*e0*r^2) ie Coulomb’s law for the force between two charged objects.
        The direction points along the vector from one charge to the other, repulsive for same sign, attractive for opposite.
        Now if you are trying to claim ‘electric’ forces are falsifying the mass, yet ESA can navigate accurately using purely gravitational equations, this has one HUGE advantage. It closely mimics the gravitational force in its functional dependence
        Fg= (G*M1*M2)/r^2 with the direction being the M1 M2 line but always attractive.
        So *at large distances*, it would work; you could partially cancel out the gravitational force with an electrostatic force, & your equations would all work.
        Of course *close in* where Rosetta & Philae have certainly been, you need a pretty bizarre situation that the charge distribution & mass distribution are coincident, or it won't work.
        But if you put *numbers* in, the required cancellation of some 80% of the gravitational force by the electrostatic force is completely unfeasible.
        Do the sums & prove me wrong please. What charges, potentials, fields are implied, how did they arise?

        So what about the second term?
        No need to bother with ‘the numbers’ here.
        It’s a vector cross product. The force vector will point all over the place during the orbit. Rosetta would be wobbling violently all over the shop; I think ESA might have noticed.
        The numbers almost certainly won’t work either in nT fields at the orbit velocities for any feasible charge, I’ve not bothered to check.
        The functional form is sufficient.

        So we have a clear observational fact to explain.
        ESA can navigate with superb precision, based on gravity alone (maybe plus a little drag close in?)
        And there is no numerically credible model of electric forces which explains that.
        So I see *NO* basis to challenge their density, & so *NO* way it can be solid rock; based, as you wish, on observation.
        (PLEASE don’t bother with conspiracy theories that they have some EU model ESA navigates by, which scores of scientists are hiding rather than someone booking a Nobel prize with it, because its patently ridiculous.)

        It’s perfectly well known there is, crudely put, an ‘electric connection’ between the Sun & comets. It’s been known since the work of Alfven, the description of the Parker spiral, it’s obvious from the direction of the ion tail. Nobody doubts or denies that.
        That does *NOT* mean that connection can do any of the things ascribed to it by the EU ‘theories’.
        These are very tenuous, very low density, very low magnetic field, very long Debye length plasmas, not lightning strikes or EDM discharges.

        I did not introduce, & have repeatedly dismissed, deep sea vents, sprites etc etc as irrelevant; they remain so.

    • hossners says:

      Hi - new here, been reading awhile. I find the 'rock' idea intriguing and simple in some ways (Occam says simpler is better). The 0.4 density seems to be a stumbling block for many. For those that say (THOMAS et al) that some sort of electrostatic charge is abating some of the gravitational force due to mass) my question is this:

      Will the 'Density' figure change as the orbit progresses?

      As the comet continues to draw near to the sun, the hypothesized electro-machining should transfer charge to/from the comet. This should accumulate and change the static field, yes? If this is a true component of the attractive force (used to calculate the comet's mass), we should see a (hopefully measurable) change in gravitational force -> mass calculation -> density figure.

      Does EU predict this?

      • THOMAS says:

        @ Hossners "Will the 'Density' figure change as the orbit progresses?"

        Excellent question, which popped into my own mind as I was writing my 27/11/2014 at 12:38 post. This would indeed be a logical expectation of the "electromagnetic-component-of-gravity" idea but perhaps the change would be too slight for Rosetta to detect it.

        May I also add that I have no idea if "EU predicts this" since I am in no way a spokesman for the EU community, nor do I have any connection with it outside forums such as this one. The ideas I express are exclusively my own, based solely on my reading of the literature.

        • Harvey says:

          Ah; it may be too slight for Rosetta to detect it, but they are getting the mass wrong by a factor of six or so because of it. There cseems to be a *slight* inconsistency here.

        • Harvey says:

          "perhaps the change would be too slight for Rosetta to detect it."

          But apparently it is falisfying the mass of the comet by around a factor of six.

          I seem to see a slight inconsistency here.......
          Either its too small to detect; or its messing up the mass measurement drastically; it can't be both.

          • THOMAS says:

            @ Harvey

            Re-read my post, Prof.

            What I actually said was that it is the *CHANGE* in the force which might be too small to detect, not the force itself. My idea was simply that any *CHANGE* in the observed density, which might be too small to be measured by Rosetta's instruments, would necessarily be conclusive proof of an electromagnetic component to what we call 'gravity' (for which we still have not the faintest understanding of fundamental causes…!).

            Please refrain from making me out to be saying what I have never said. Your reading of my comment was presumably not willfully misleading but simply inattentive.

            More cynically, I am also sure that even if such a change in ‘gravitational’ attraction were to be observed and disclosed, it would be dismissed as being either statistically insignificant or simply the result of ‘noise’. As you must inevitably know as an academic scientist yourself, fully conversant with the ‘mores’ (Latin = ‘morals’) of your wider community, the astrophysicists who are interpreting the data collected by the Rosetta/Philae engineers have as much at stake in defending the standard model as is the case in any other branch of science (e.g. the ‘climate scientists’ (scientists ?) I referred to in my recent post on another thread:, in response to your accusation of ‘libel’ on my part.

          • hossners says:

            No real inconsistency here: The effect could be large, but the *change* in the effect as the orbit progresses could be small.

            It might also be hard to determine if a change in measurable mass is due to the erosion of the comet or change in static charge, or both. Comet should have less mass due to erosion, but might gain mass if the hypothesized static charge gets closer to the sun's equilibrium.

            Frankly, unless comets are notorious for orbital anomalies, it seems unlikely its mass will change in an unexpected way. Some other explanation for the low density seems more likely, although I am not aware of any hypothesis to explain a 'hollow' comet, EU or Standard model.

          • THOMAS says:

            @ Harvey

            Please re-read my post.

            What I actually said was that it is the *CHANGE* in the force which might be too small to detect, not the force itself. My idea was simply that any *CHANGE* in the observed density, which might be too small to be measured by Rosetta's instruments, would necessarily be conclusive proof of an electromagnetic component to what we call 'gravity' (for which we still have not the faintest understanding of fundamental causes…!).

            I’m sure that your misrepresentation of my comment was not deliberate but more the result of inattentive reading.

            It seems likely, in any case, that any slight change which might be detected in the gravitational field will be dismissed as being either statistically insignificant or simply noise.

          • Prof Harvey Rutt says:

            Yes, I read 'change'; it is still totally inconsistent.
            If it is cancelling 80%, given that the distance to the sun, magnetic field, solar wind flux density, will all change massively, it is not remotely credible the change would be undetectable.

          • THOMAS says:

            Sorry Harvey, I honestly don't understand your prose here. Could you clarify your meaning please? I repeat, I was speaking only of a possible *CHANGE* to the hypothesized electromagnetic component of gravity, which might be too small to be measured by the Rosetta instruments.

          • Prof Harvey Rutt says:

            No reply button in the appropriate place; possibly an iPad problem.
            The supposed force is said to be cancelling something around 80% of the gravitational force.
            Rosetta can measure that to high accuracy; some time back they gave a 10% error bar I think, but by now it will be *far* better with continued orbit manoeuvres and tracking.
            This cancelled by force is supposed to originate from electrical effects induced by the sun - there is of course no remotely credible mechanism for that.
            But 67P will move some three times closer to the sun; solar wind density will increase by a factor of around nine, magnetic fields change substantially.
            It is not remotely credible that when the influence supposedly generating it chances by a factor of nine, the resulting change will remain constant to of order percent.

  • Marco says:

    Hi Thomas, I perceive that EU is a bit of a "catch all" as far as phenomena like comet Holmes, anomalies and other unexplained space data.
    It is clear to me that much more data is required to get to the bottom of these "surprises", and at least one major assumption of cometary models is completely wrong *but which one?*
    My assumption is that a lot of cometary science is right on the money, but a lot of it is "poisoned fruit" because of an incorrect assumption in the model of comet formation. Sorting it out is very difficult, but EU really throws out the baby with the bath water.

    • THOMAS says:

      Hi, Marco

      To take your comments from bottom to top:

      "EU really throws out the baby with the bath water"

      Quite the contrary: the EU model allows all the bathwater to gurgle away down the plughole where it rightfully belongs, just leaving the happily kicking baby intact, with its billions of electrically-driven neurons, nerve-cells and every other type of electrically-driven cell, as in real life. (Apologies to certain posters on this blog who prefer numbers to real-life observations or comparisons).

      " least one major assumption of cometary models is completely wrong *but which one?*"

      Just *one*? Are you kidding? Standard cometary theory is built, tier by tier, on literally * hundreds* of *assumptions* of the wider Big Bang theory which cometary theory is a small but essential part of, each one of which is dependent for its “credibility” on those previously asserted on the tier bellow (T-1). It's a bit like a multi-mega-storey house of cards: Take away a few of the lower-tier cards and the whole edifice will start tumbling down and everything will ultimately lie flat on the ground so that we can at last start constructing a steel-girdered framework of cosmology, built on rock-solid foundations, in its stead.

      “I perceive that EU is a bit of a "catch all" as far as phenomena like comet Holmes, anomalies and other unexplained space data”.

      That is *your* “perception”, born of insufficient familiarity with the EU paradigm and the vast body of observational evidence which underpins it. In reality, the number and diversity of “unexplained space data” (I assume you mean “unexplained by the standard model”) are so vast that they cannot even begin to be listed and explained on a forum such as this one, on which we are privileged to be able to air our personal positions and views but without abusing the hospitality of our hosts.

      I would simply like to point out that if we were to apply the sacrosanct “scientific method” which all scientists necessarily pay devout lip-service to, whatever their branch of science, *one single* significant, incontrovertible observation shown to be totally incompatible with the existing standard model should be sufficient to invalidate the theory in question and require the formulation of a new one. In the case of cometary science, for example, the Comet Holmes explosion on its way out beyond the orbit of Mars in 2007, or the double flash of the Deep Impact collision with Comet Tempel 1 with the attendant vast quantities of “talcum-powder-like dust” it generated in 2005, or the multi-million-mega-ton power of the explosions, (comparable to thousands of H-bombs) of *each* of the 21 fragments of Comet Schuhmacher-Levy 9 on entering the atmosphere of Jupiter in 1994 or the…etc. etc. (I could go on for hours) would have been sufficient to invalidate any self-respecting “dirty snowball” theory. I repeat, *a single one* of these observations. Instead, each successive falsifying observation is acknowledged at the time as being “astounding”, “challenging”, “unexpected”, “not fully understood”, etc. etc., but is then quietly swept under the carpet, never to be mentioned again in polite Establishment circles, in the hope that it will eventually be forgotten. The “dirty snowball” model, for its part, is a Christmas Tale dreamt up at a time well before we had the first, faintest, distant, blurred image of a comet nucleus. It could no doubt be given credence at the time, if only for lack of falsifying observations, but the Rosetta and Philae images have now utterly discredited it.

      The EU is not a “catch-all” form of reasoning, Marco. The EU model is in no need of new recruits via any feeble forms of evidence it might be able to glean to attempt to support a failing model. Personally, as a “citizen scientist”, I abandoned the increasingly implausible standard model around 15 years ago and, after reading around for something more in line with correct scientific method, became interested in the wholly observation-based EU model a few years later. I believe that the evidence for the predominance of the +/- electromagnetic force in the workings of Nature from the almost-infinitely-small up to the almost-infinitely-large, throughout the Universe, is simply overwhelming (albeit in ways which, at many levels, are as yet only partly understood) and will ultimately be admitted as such when those two or three cards are finally pulled out of the very basis of the standard theory card-house by the aptly/ironically named Rosetta mission.

      Still waiting for the CONSERT data on the composition of the nucleus and the RPC-IES data on the comet’s plasma environment, BTW. It’s a long time coming.

      • Marco says:

        If the interior of the comet is found NOT to be solid rock, does this falsify EU or not? I suspect that some other EU follower is going to come here and claim that (whatever is found by CONSERT) was predicted by EU. Not you- You might eat humble pie, but EU will roll merrily along somehow...

        • THOMAS says:

          Hi, Marco,

          As I have recently stated on another thread, I am in no way a spokesman for the EU community and I have no contact with it/them.

          Personally, however, I am perfectly happy to go on record as saying that if the data collected by the CONSERT instruments is finally archived and made available to the scientific community at large and if it shows unequivocally that the composition of the interior of the comet is totally inconsistent with the idea of its being made of solid rock, as the 0.4g/cm3 suggests, then I will personally consider the EU model of comets to be invalidated.

          If, on the other hand, this data is never released for analysis and interpretation by qualified scientists in the wider scientific community and if the only permitted analysis is only ever the one made by the astrophysicists in the Rosetta mission CONSERT team and other associated mainstream astronomers, then I will have no reason to believe that the EU model has been falsified should the “findings" announced be less than totally unequivocal.

          I repeat that I have the utmost admiration for the decade and a half-long engineering accomplishment which has made the acquisition of the different data-sets possible. My only worry concerns the use which will now be made of them by mainstream astrophysicists. Given that it is the European taxpayers who have been funding the whole mission, these data-sets *must be archived* according to the prescribed procedures (if only after the 6-month waiting period announced in advance by ESA), so that there can be no possible doubt of scientific malpractice such as has been routinely observed in other scientific fields, such as that of "climate-science" (cf. the 2009 Climategate scandal), for example.

          It would now be interesting to know if any standard “dirty snowball” supporters are also prepared to go on record as saying they consider that their standard model would be falsified should the CONSERT data prove that the nucleus is actually made of rock.

          For that matter, are you prepared to make the same commitment yourself, Marco, regarding the panspermia model you defend?

          • Marco says:

            Hi Thomas, that does clear up a couple of things for me. I also cannot speak for "panspermia", but I believe that CONSERT data will be conclusive that the interior will not be solid rock, ice or homogenous at all. However it will be completely inconclusive with regards to panspermia. CONSERT will not have the resolution to show structure inside the comet other than that it will be complex. Evidence of life will also be inconclusive for the moment, although a large preponderance of homochirality in organic molecules detected by COSAC will be hard to explain if the instrument gets some of that crude oil from the surface...
            If the CONSERT data shows rock, or snow, homogenously, I will probably eat humble pie, but it will really challenge my own understanding of either the laws of physics or the origin of life or both.

          • THOMAS says:

            Thanks for the honesty of your response, Marco.

            I remain curious to see whether any defenders of the *standard dirty snowball theory* are now prepared to match us by making a similarly frank commitment on behalf of their preferred model....

          • Marco says:

            Interestingly, to take prof Harvey as an example, they truly believe they are not wedded to the Whipple model, and feel they would change to another model in a minute given enough evidence. I think in reality, with the absence of consensus within the scientific peer group on what to change to, they will continue to squeeze more "strange" "enigmatic" or counterintuitive data into the model regardless. Close to the end of the model, it might actually become comical.

          • THOMAS says:

            Marco, I have been observing the model for several decades. I was actually a follower myself up until about 15 years ago, when I finally realized that the purely intellectual constructs which were routinely being appended to the model in an attempt to account for increasingly discordant observations (both images and data) had become not simply comical but positively ludicrous. The worst (= most comical) is perhaps still to come.

          • Prof Harvey Rutt says:

            What neither of you can see is the complete inversion of reality in these posts.
            I have absolutely nothing 'invested in' any model, professionally or emotionally.
            I want a model which:
            - is consistent with reliable data
            - is consistent with known physics qualitatively
            - is credible numerically when some mechanism is proposed.
            - if it proposes new physics, fine, but that needs very good evidence and analysis and consistency with known physics.
            Should ESA suddenly, and extremely improbably, announce they got the density wrong by a factor of six, That is not going to ruin my day; it will be 'ok, think again' time.

            In contrast, highly reliable data on the density is just said to be clearly wrong - with no credible mechanism for that at all. It's claimed to be wrong *purely* because it doesn't fit some pet model. Multiple data measuring neutral water - as opposed to OH - in the coma of multiple comets is ignored;, measured by different instruments, different methods. Calculations showing that sure, solar wind sputtering produces tiny levels of OH, not remotely consistent with the amounts in the coma, is ignored. The inconsistency with our moon - three times closer to the sun, but no coma - is ignored. The huge number of papers modelling the interaction of comets etc with the solar wind are ignored. Ridiculous comparisons are made between an EDM pit 20um across, made under oil, across a gap of microns, to events supposedly digging out craters whose linear dimensions are bigger by say 10^7, so volume and required energy more like 10^21 - that's somewhere around comparing the effects of the explosive in a Christmas cracker to a nuclear bomb. A picture of a semi melted grain of Fe2O3 on a mm scale made at high pressure, where surface tension for example is a big effect, is compared to things km across with utterly different forces determining their shape - and other, different shaped grains ignored.

            There are, I'm glad to say, lots of curious, very puzzling features of comet behaviour. They will be explained by the data and rational thought, not by that sort of, frankly, nonsense.
            I don't follow *any* model. I follow the data and the physics. I don't try and rubbish inconvenient data.

            The followers of EU at times seem quasi religious about it. If you disagree, you are clearly the dark side, subject to ad hominem attacks. Anything that doesn't agree with pre-concieved views is 'obviously wrong' - indeed it's already been suggested, preparing for bad news, that the CONSERT a data is being 'cooked'.

            Where data is concerned I'm 'The Vicar of Bray' I go where the data takes me, not where preconceptions from a model take me.

          • Prof Harvey Rutt says:

            One thing that intrigues me is the fixation on the CONSERT data. The far simpler, direct determination of the mass is somehow unacceptable, but CONSERT is, it seems acceptable.
            But CONSERT data is really complex. It's limited in resolution at 90MHz, and as they only got limited time the S/N maybe is not great, and they won't have many orbits, ie paths through the comet. It will have to be inverted using constraints, most obviously the shape - and very probably the inversion will be constrained to fit the obsrved density. On top of that they will have to make assumptions about dielectric constants. Nothing like it has been done before to my knowledge.
            This is not going to yield some high resolution MRI like image of 67Ps interior. It will yield a best efforts fit to constrained models, possibly several such.
            So you will have *lots* of opportunity to complain about the result, for sure.
            (In contrast, locating Philae with line of sight signals was a far easier task, far better S/N, no model needed, two orbits and you've got it.)

          • Marco says:

            Hi Prof, I think you protest too much in regards to EU. You made no mention of my ideas or criticisms of the "establishment" and I mean that in the nicest possible way. If you really were like the Vicar of the Bray, you would be much happier with the title of this blog entry of many comments "Philae settles on some unknown cold hard black substance" rather than where the preconceptions of the model took it to say something about "ice".
            The data is telling us the surface is dry, and no matter how you dress up other data such as water vapour, it has nothing to do with ice on the surface or near subsurface. THIS IS WHAT THE DATA IS TELLING US. For collimated jets of vapour/dust to occur, requires large subsurface chambers, with vapour with dust particles travelling through small nozzles at supersonic speeds. This does not break any physical laws, and I am quite satisfied that it happens, but it means that there are much higher pressures and temperatures involved than what is modelled as a solar thermally driven process into a vacuum. We should not expect ice on or near the surface.
            I consider the dismissal of the low density calculation by Thomas and other EU "followers" as denial of forensically determined facts about the mass and volume of C-P. I also however see the heading of this blog entry to be a denial of the facts. If, you, prof were not invested in sublimation as a source of the vapour, you would see this.

          • Marco says:

            Hi again prof. I agree with you completely on the CONSERT data. Like I said, I severely doubt that any unhedged conclusion can realistically be made, especially given the uncertainty in finding Philae, and perhaps the failure to find him quickly may be indicative of the tentative nature of the technology. However, that being said, it is a real and first opportunity to rule in or out certain possibilities of the interior. It is at the very least, data about the interior that we can argue about, rather than complete speculation.
            Being that the outside has no water ice (that is what the data is telling us) we can make better guesses about the origin of water vapour.

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