Rosetta in 2015

Before the Christmas break we left you with a bounty of comet images to create a movie – if you took on the challenge, do post links to your videos on the relevant post: CometWatch – the movie. We are looking forward to seeing your mosaics and movies!

We were also keeping our ear to the ground for an update on the whereabouts of Philae, but attempts to identify the lander in high-resolution OSIRIS images acquired from a distance of 20 km have reportedly not yet been successful. (Note, the link is to a German news story in which OSIRIS PI Holger Sierks told the Göttinger Tageblatt “We have still not discovered the lander.”) The scientists continue to scour the images for confirmation of the landing site.

Four-image mosaic of Comet 67P/C-G comprising images taken on 1 January 2015. Credits: ESA/Rosetta/NAVCAM – CC BY-SA IGO 3.0

Four-image mosaic of Comet 67P/C-G comprising images taken on 1 January 2015. Credits: ESA/Rosetta/NAVCAM – CC BY-SA IGO 3.0

Rosetta is now orbiting comet 67P/C-G at a distance of about 30 km. The images included in today’s post were the first to be taken in 2015, acquired shortly after midnight UTC spacecraft time on 1 January from a distance of 28.4 km from the comet centre. The mosaic, oriented with the smaller lobe on the right and the larger lobe on the left, has a resolution of 2.4 metres/pixel and measures 4.1 x 4.0 km. The four individual 1024 x 1024 NAVCAM frames making up the mosaic, which each measure about 2.5 km across, are provided at the end of this post. Because rotation and translation of the comet during the imaging sequence make it difficult to create an accurate mosaic, always refer to the individual images before drawing conclusions about any strange structures or low intensity extended emission. For example, there are artefacts in this mosaic on the far left and towards the centre of the image, respectively.

Montage of the 1 January 2015 images.  Credits: ESA/Rosetta/NAVCAM – CC BY-SA IGO 3.0

Montage of the 1 January 2015 images. Credits: ESA/Rosetta/NAVCAM – CC BY-SA IGO 3.0

Rosetta will continue in its 30 km orbit until 3 February, before building up to its closest flyby yet. On 4 February, Rosetta will start to move some 140 km from the comet, before swooping down to just 6 km from the surface on 14 February.

This close flyby will allow instruments to take images and spectra of the surface with unprecedented resolution and to directly sample the very inner cometary coma in order to learn more about how the comet’s characteristic coma and tail are created.

After this exciting event, Rosetta will continue making a series of flybys of the comet, the exact distance determined by the activity of the comet at any given time. The activity is expected to increase over the coming months as the comet moves ever closer to perihelion on 13 August. That is, the closest distance to the Sun along its orbit, which for 67P/C-G is 186 million kilometres, roughly between the orbits of Earth and Mars. Rosetta will be watching as the activity increases and then subsides again, and how the comet’s surface features change and evolve during this period.

Scientists also hope that the increasing solar energy in the coming months will be enough to revive the lander Philae from its hibernation.

In between these mission milestones there will be regular releases of science papers and data (dates of data releases TBC). Presentations of the latest analyses will also be made at science conferences over the course of the year, including EGU (April), EPSC (September) and AGU (December). We’ll continue to report on the key science results here on the blog and/or via the main ESA web portal.

We’ll also be continuing with our regular CometWatch releases via the blog.

The individual 1024 x 1024 pixel NAVCAM image frames for today’s CometWatch entry are provided below. As ever, we encourage you to create mosaics and share them on your social media channels with the credit line: ESA/Rosetta/NAVCAM – CC BY-SA IGO 3.0.








  • Dave says:

    Summary 2014- Rosetta surprises and anomalies through the past year
    There were many surprises during 2014 thanks to ESA, and many others, what a fabulous mission and fabulous execution in getting a Lander on to the comet and then succeed in getting some data from the surface.
    I have briefly listed some of the major surprises, who could of predicted that the comet should turn out so different to expectation. How much more interesting has the project been because of these surprises, and how much more will we learn about the environment we live in from the unexpected data?
    1. Comet activity Flared up briefly while still very far from the sun, and before Rosetta had caught up with it, Not so much was made of this, but it seemed to be too far away from the sun to be warming from the sun. It remains to be adequately explained
    2. Density was revised slightly early on , 0.3 to 0.4 if my memory is correct. So dirty snowball people thought it too high, but people expecting something like rock, based on pictures from recent comets were still thinking the figures could almost be up to an order of magnitude out.
    Then the comet was found to have a hard shell with no ice present, then the figures from Consert declare that the comet is homogeneous – So no voids, this puts the current density figure even further into the spot light. Figures from Consert though don’t explain what the core is made of, it was designed specifically to detail ice structures, so is there any in the core? Is the density also homogeneous?
    At one stage the discussion about the density on the blog was one of the most contested, so I guess this will result in a lot of interest.
    -Can the density really be so far out? – What can be the cause? Is there something we still need to understand. (Its difficult sometimes to trust Gravity, especially when our galaxies refuse to fly apart. So is there something we are missing)
    This anomaly may threaten to be one of the biggest conundrums
    3. Temperature (average) of the Comet surface was then measured to be about 30 degrees higher than expected.
    Again not too much made of it and still not adequately explained, when temperature maps were issued they were not much to help ascertain what was going on, also resolution of the temperature maps was a bit coarse. Could of it been electrical activity? The sun was a long way away when first measured.
    This too, so far has not been adequately described.
    4. Dust, for the first particles captured very early on, there was surprise that dust had been detected from so far away, there was also surprise at the sizes, there was a promise to update when some analysis was available, although this was done, not much was given away.
    Then the most recent article on dust (MiDAS atomic force microscope), The particles were too big to fit the microscope. A bit of a surprise, although the designer says not totally unexpected, the equipment was not set up to measure such large pieces of dust, also it was said to be Fluffy, from which you could infer it may of been of electrical origin
    5. Ice, Not detectable on the surface, from Rosetta instruments, it then became very puzzling that people have continued to state that sublimation was the cause of the jets of gas and dust even though no ice is available to sublimate from the surface.
    The argument then changed stating that ice was below the surface. This also seemed odd, as not even Consert has so far found ice under the surface, and it was designed specifically to detect ice and its structures.
    Not only that the visible evidence is just not there, when you look at the carved areas, especially the neck, there still appears no ice visible or detectable.
    Phillae landed and we had the statement, that the hammer and hit something not inconsistent with hard Ice. Thus confirms only that the surface is hard but not how hard, so far Phillae has not detected ice on the surface either.
    Recently though, information released from Ptolomy indicates that h2o is in the atmosphere just above the ground. At last some information, but how did it get there if there was no surface ice to sublimate it? So even with this experiment there is still a large anomaly to solve, we have water in the thin 67p atmosphere but seemingly not on the comet.
    In a further release from ESA, it confirmed that the shiny bright patches on the comet are not Ice.
    Again this is confirmation that the surface is not sublimating, IT IS A BIG SURPRISE
    If we look at the proposed model for sub surface sublimation, we have been asked to accept that ice close to the surface sublimates through a jet/nozzle in the ground as it heats up and sublimates. The surprise is we cannot see this happening anywhere yet. The origin of many jets can be traced back to flat ground or possible sharp edged features or even boulders.
    The mechanism suggested for the pressurised jet from underground sublimation is compared with high pressure gas exiting a high pressure vessel with a small hole, hence very high ejection speeds can be achieved. This could be true but as the vent equalises its pressure with the light atmosphere of the comet, then the pressure will drop and so too will the ejection speed, until the source is spent.
    This does not appear to be seen either. Shots taken days or weeks apart of the jets of gas & dust seem to be coming from the same place, and although there is some wax & wane in output, there seems to be a steady increase in intensity from the same area. How can this be explained by such a model?
    So it would be surprising if these sublimation mechanisms were the cause of the jets because there has so far been no ice detected on the comet from which to sublimate and the mechanism suggested for sub-surface ejection, does not seem to reflect what we see.
    In addition to all that, the jets of gas and dust that we can see have large diameters so how can this be produced from a small hole in the surface of the comet, and what makes the ejected material stay in a collimated stream, certainly not any effect from the hole it came from.
    It is surprising that so far there is not much of a steer from the rosetta team that could give us a better idea on the mechanism. There should be good quality photos, and if the method is electrical in nature, not mechanically forcing gas through a small hole, then there are plenty of instruments to detect what is happening. Rosetta can measure magnetic fields, plasma and current flow, so far there has been little release of this information.
    However in one of the last blogs from ESA before Xmas, they did mention that the jets coming off the head of the comet were due to electrical sputtering of the surface, an extremely surprising statement to come from the team
    6. Morphology Its one of the craziest landscapes you will ever see, so definitely a very big surprise, as one person commented, ‘Its no dirty snowball is it ?’
    It will certainly take some explaining, most of the craters do not look like collision or volcanism, so I guess it was no surprise, that nothing was presented at the AGU. I think more time is probably required.
    7. Electrical activity, It must be a surprise that virtually nothing has been reported, considering the equipment that is available. Also nothing reported at the AGU. There has been huge discussion on the blog, so some data to confirm what level of activity there seems overdue.
    Some of the disagreements on the blog need some info ie - No ice so how can there be sublimation vs not enough power to sputter bulk material electrically- looks likely to continue until there is some data.
    8. No use of enthusiastic amateurs to help find Phillae. Plus phillae still lost !
    This is a surprise and it has been used on other projects, great to have some extra hands and great for schools and overall engagement in space science. Another PR opportunity lost I think, even if it had turned out to be futile.
    9. The wrong water
    This was probably the most surprising statement from the mission so far, not merely did it state that it was the wrong water, it also stated that there was no possibility that comets like 67p could have been involved in seeding the earths oceans.
    It was therefore surprising that the Ambition video was not taken off the blog, it directly contradicts the hard statement above. The video also states ‘making science fiction science fact!’ which also appears wrong when compared to the above statement.
    There was little or no explanation of the heavy water (I have not seen the paper) and how the comets water came to be so different, Is the comet from a completely different region of space or is the water in the coma made from much younger material than the seas on the earth? Does it have any impact of the accretion theory of our solar system?
    Anyway an answer was found very swiftly,
    -it must be the asteroids that have seeded the earth’s oceans?
    This is in itself a very striking statement, with apparently not too much to back it up. We have always taken asteroids to be made of rock! If there is water in them (some evidence for it in some types of asteroid) or in the rock they are made of. Then when hundreds of thousands or more hit the earth to seed the oceans, what has happened to all the rock that the asteroids would also bring? How can two thirds of the earth be ocean, if the process of seeding brought with it an overabundance of rock. I think it would be very surprising if it were true.
    Anyway no sooner was this made public then the AGU started, and from two different sources came the revelation that the earths mantel could contain enough water to fill the pacific! I think one paper was presented at the AGU and another similar paper was published in a science journal from a different university.
    Surprise, Surprise, do we need asteroids and comets at all to give earth water?
    Where does all this leave us?
    Many, many surprises, probably a new comet model required, not just the construction and the evolution of the comet, but surely the theory that the earth’s main source of water must have been seeded, surely this has to die also, the current model is just not believable, even the evidence above indicates no water ice on comets and the water that was made in the comets atmosphere is not the kind of water that’s suitable for earth!
    How many more nails do we need before we throw the std model away and start again based on good data, ESA must have some great data, so must be in the forefront for a guide to a new model.
    2014 was an exciting year thanks to ESA, with many surprises, lets hope 2015 is even better. Lets hope some of the surprises begin to make more sense and a common narrative begin to form.

    • THOMAS says:

      Great summary Dave. I wanted to do something similar just to while away the time but the time somehow whiled itself away all by itself and I didn’t get round to it….

      You’ve put your finger precisely on the most serious problem of all concerning the various anomalies you have listed, which is the non communication by virtually every one of the Rosetta instrument teams of anything but the most succinct information or surmise. They necessarily have huge amounts of henceforth deciphered data which is simply being withheld. We actually learnt almost nothing new about 67P’s characteristics and behaviour from the AGU presentations, as symbolized in particular, and from the very outset, by Claudia Alexander’s diversionary video presentation of the totally hypothetical Grand Track accretion model for planetary formation during the opening press conference on the Wednesday. It was if we were being prepared to expect the worst in terms of the quality of the “information” to come. We were thus neither particularly surprised nor disappointed by what followed. Claudia Alexander truly set the tone.

      The only slight omission I can find in your summary concerns the persistent refusal of the OSIRIS team to share the body of their close-up images, even with the other Rosetta and Philae instrument scientists, presumably for fear of leaks by competing (?) teams… The OSIRIS images necessarily hold keys to several of the major anomalies you describe. They also add still further mysteries for the standard theory, such as the “dinosaur eggs” observed at the bottom of “pits” and embedded in cliff walls. Mouth-watering!

      Humanly speaking, we can fully understand the reported exasperation of other Rosetta instrument teams with their OSIRIS ‘fellow scientists’. It’s as if the cameraman on a major, publicly-funded, geographical documentary project simply did a bunk with his footage so as to be able to publish it independently, leaving the other members of the team (anthropologists, botanists, geologists, biologists, zoologists, etc. etc.) to make do, in the meantime, with whatever information they had garnered and recorded personally.

      Scientifically speaking, everyone is naturally free to draw his/her own conclusions from this withholding of essential information. My personal hunch is that the findings by EVERY instrument team are so utterly discordant with standard theory that the data (along with the required patches) will truly be a long time coming.

      • Peter says:

        Good Evening,

        as a simple ciitizen of a major payer for esa i wiould love to comment on the publication issues. In my opinion there is an obligation for esa to make the images, even the raw ones, public. I dont want to criticise the quality, i dont want to comment on anything. I just want to see for what i have payed for. This is my money esa is unsing.

        Cheers and every respect for the Rosetta Team.


    • Ian says:

      A lot of stuff in that post, Dave but
      1. There are adequate explanations for the 67P flare-up just as in the bigger Holmes flare-up, e.g. pockets of ice being exposed.
      2. I recall that the density before Rosetta was 1 g/cc. The cause of the increase seems obvious -.the strange shape of the comet. The density is likely to remain at around 0.4 g/cc. This figure does not depend on the internal structure of 67P.
      3. There is no detection of "electric activity" on the comet surface so that cannot be a cause of the higher than expected temperature. It is more likely to be a fault with the modeling of the temperature.
      4. .Nice discovery that the 67P dust particles tend to be larger then expected from other missions. No one should infer from a comment that "fluffiness" of the dust is of electrical origin. Snowflakes are "fluffy"!
      5. Ice was not detected from Rosetta but detected by MIDAS (and harder than designed for). This was consistent with hard ice . You get jets from sublimation of subsurface ice where the gas is shaped by pits or fissures or chambers. Philae has detected ice on 67P because that is the only physically possible option for a comet made up of dust and ices.
      6. Morphology: There are some unexpected features but most have been seen before. Probably caused by its strange shape. Of course it is not a "dirty snowball" - it is basically2 dirty snowballs joined together.
      7. It is no surprise that no "electrical activity" has been reported yet because the teams are probably still analyzing the data! No press releases implies no surprises in the data so far.
      8. Enthusiastic amateurs are free to look for Philae.
      9. The wrong D/H ratio is evidence that asteroids provided most of the Earth's oceans. The wide range of D/H ratios between comets is evidence that they originated in different places.
      Asteroids include water which can be significant in many chondritic asteroids . There is evidence that some have quantities of ice in them (main belt comets) or even an internal liquid ocean for Ceres.

      There will be an updated comet model from some of these findings, not a new model.

      • THOMAS says:

        @ Ian

        “1. There are adequate explanations for the 67P flare-up just as in the bigger Holmes flare-up, e.g. pockets of ice being exposed.”
        Sorry? According to the laws of physics, “pockets of ice being exposed” (by what precise phenomenon, BTW?) can in no way “adequately explain” these flare-ups since ice simply does not sublime at the temperatures associated with the distances from the Sun at which these events occurred (even in the case of 67P, let alone Comet Holmes!).

        “2. […] The density is likely to remain at around 0.4 g/cc. This figure does not depend on the internal structure of 67P.”
        It certainly does! If the interior is actually made of rock, the 0.4 g/cc figure will need to be revised upwards by a factor of around 7. And even if the homogeneously solid interior detected by the initial CONSERT data were to be purely ice (which now seems extremely unlikely), as in the standard dirty snowball model, the 0.4 g/cc figure is already wildly inaccurate. The density figure depends TOTALLY (and BY DEFINITION) on the internal structure of 67P.

        “3. There is no detection of "electric activity" on the comet surface.”
        This is merely your personal belief, linked to your complete faith in the dirty snowball model. As Dave pointed out, the phenomenon of “sputtering” was evoked by mission scientists during the AGU presentations to explain the detection of metal ions like Sodium, Magnesium, Zinc and Iron, as reported by Robin Sherman in his extremely useful summary:
        Furthermore, the origin and cause of the long, persistent, dead straight collimated dust-jets are more consistent with an electrical explanation than with one based on simple outgassing.

        “4. .Nice discovery that the 67P dust particles tend to be larger than expected from other missions. No one should infer from a comment that "fluffiness" of the dust is of electrical origin. Snowflakes are "fluffy"! »
        One hypothesis is that the « fluffiness » of the 67P dust particles comes from the electrostatic clumping of tiny dust grains. This would also explain their lack of solidity. As for snowflakes, we do not know precisely what causes their formation. It may also have something to do with electrostatic charge.

        “5. Ice was not detected from Rosetta but detected by MIDAS (and harder than designed for). This was consistent with hard ice. »
        Ice was certainly NOT detected by MIDAS. Stating that the “hard” surface was “consistent with hard ice” amounted to simple wishful thinking. The inability of the drill to make any inroads into the hard surface it encountered is also, even more obviously, consistent with solid rock, a hypothesis which is abundantly confirmed by the CIVA images of Philae’s last resting place. Impossible to believe that these cliffs and boulders are actually cleverly-disguised lumps of ice (like all the other cliffs and boulders to be seen on every surface of the comet…).
        As for your assertion that “Philae has detected ice on 67P because that is the only physically possible option for a comet made up of dust and ices”, this a just circular argument, again based on simple faith. No further comment required, except to ask why we even bothered to spend 10 years and over a billion euros going to explore this comet if we already knew all the answers, as your circular reasoning seems to imply….

        “6. Morphology: There are some unexpected features but most have been seen before. Probably caused by its strange shape.”
        I love the euphemism “some unexpected features”. In reality, absolutely no single observed feature of 67P was “expected”, even in the worst nightmares of standard astrophysicists. Some of them have indeed been “seen before” on the other comet nuclei we have imaged. They were already a HUGE surprise. And not one of them has ever been “adequately explained” AFAIK.
        And how can “its strange shape” have caused these “unexpected features” (or vice versa)? I suggest instead that, in all logic, both are the effect of common causes, which have nothing whatever to do with dirty snowballs.

        “7. It is no surprise that no "electrical activity" has been reported yet because the teams are probably still analyzing the data! No press releases implies no surprises in the data so far.”
        Sorry? Virtually every instrument team is reportedly surprised by their findings, otherwise they would have been announcing their initial evidence in support of the standard theory. It is this total surprise, well documented by Dave, which explains the lack of official information (in particular from the OSIRIS team…).

        “8. Enthusiastic amateurs are free to look for Philae.”
        Why not.

        “9. The wrong D/H ratio is evidence that asteroids provided most of the Earth's oceans. The wide range of D/H ratios between comets is evidence that they originated in different places.
        Asteroids include water which can be significant in many chondritic asteroids . There is evidence that some have quantities of ice in them (main belt comets) or even an internal liquid ocean for Ceres.”
        In reality, Kathrin Altwegg’s interpretation of the ROSINA findings clearly creates far more problems for the standard theory than it solves. Huge amounts of water in the billions on billions of rocky asteroids which must have crashed into the Earth to account for the unimaginable volume of the ocean’s waters? Where did the rocks from these asteroids go?
        I admire your faith in every new reworking (aka “patch”) of the standard theory. But please do not claim it has anything to do with the scientific method.

        I assume this is what you acknowledge yourself by your parting comment: “There will be an updated comet model from some of these findings, not a new model.” You clearly trust the current Establishment to do everything it can to maintain the dirty snowball status quo. For my part, I remain confident that the overwhelming weight of gain-saying evidence will necessarily end up by enforcing a complete change of paradigm despite the dead weight of your 60-year-old dirty snowball model.

        • Prof Harvey Rutt says:

          Limiting myself to one aspect.
          We have *DATA*
          We know the volume of the comet.
          We know the mass of the comet.
          So we know it's density.
          Nothing has been proposed that can conceivably falsify those numbers and be consistent with everything else, in particular ESAs ability to navigate very precisely round the comet.

          Models of its internal structure need to be consistent with THE DATA.
          We do not 'revise the density by a fact or seven', in total conflict with THE DATA, to fit some pet model.

          You adjust the model to the data; not the other way round.

          • Jon says:

            Not to be nitpicking, but didn't ESA say that the density value would be updated in early to mid '015 when the dark side volume was completely resolved, or has that been done? Not that it could change the value much, just saying!

            I get the part about manuvering the craft for things like a precision drop landing but haven't the orbits been adjusted with flight assistance?

            For what it's worth I think the engineering aspect to this mission is the unsung part.

          • THOMAS says:

            Methinks you are over-selective in your choice of "data". The initial *CONSERT* data, while not settling the debate between ice, rock or any other mystery substances, has at least firmly established that the interior is homogeneously solid. There thus seems to be a direct contradiction between this CONSERT data and the announced density figure of 4g/cm3, particularly since the greater part of the outer surface is visibly composed of layered rock in the form of spectacularly solid-looking cliffs, boulders, buttresses, outcrops, etc. Even more strikingly, this is also the case with the sheer, 1000 metre high x 1000 metre wide cliff making up the underside of the 'head' lobe, and which is arguably an image of the substance composing the *interior* of the comet, should there be confirmation of the erosion-of-the-neck hypothesis suggested by the concentration of the dust-jets in this region.

            Models of the comet’s internal structure ALSO need to be consistent with THE CONSERT DATA.

            What substance do you propose? It certainly can’t be the ice of the dirty snowball model, otherwise the overall density would already be, at the very least, well over twice the announced figure.

          • Judy Hawkins says:


            On the issue of the density, and the likelihood of its being revised by more than a small amount:

            There are a number of freely available documents -- phd theses and the like -- which explain how it can be that we have a good approximation of the mass and the volume, without having had to land on the comet and sample it directly.

            My personal collection is one that I generated by searching on "pdf 67P" -- you can turn up a whole lot of very solid, well constructed papers on the topic, and which have rafts and rafts of references to further docments to expand your understanding of the underlying science: the observations, the hypotheses, the disagreements and the reasons for some of the more generally accepted conclusions, including the measurement of the density.

            I invite you to take the time to read through what's available -- all of it free, all of it on the web for someone willing to put a little effort in. I'm not a scientist, I'm a software engineer, and I don't have much time to spend on my comet reading, but I've had enough to develop an appreciation for just how much really sound science has gone into some of the more widely held conclusions about comets.


          • Harvey says:

            Thomas, CONSERT data so far is very limited. About the only thing they have concluded to date is that, *for a very limited number of transit paths*, it is pretty homogeneous on a few metre scale. Thats *all* The instrument is intrinsically unable to say anything about finer scales (~10MHz bandwidth.)
            They didn't get enough time to conclude much more, & not knowing the lander's position doesn't help.
            CONSERT data essentially gives a range of delays & attenuations, which depend on the path length *and*, unknown, complex dielectric constant. You have to fit that to models using credible materials & mixtures. Given the 90MHz frequency, the very limited CONSERT data shown at the AGU seems perfectly consistent with a porous ice/rock/dust mix of faily fine scale - for those very few paths. There is no possibility of a fuller tomographic recontruction whithout much more data.

            Nothing in CONSERT data so far is in conflict with the density data.
            The density data is so solidly based, on such a huge amount of internally consistent information, that were they in conflict I suspect the prime suspect would be CONSERT - a very clever, but novel instrument with very limited data as yet.

            Appearances are of little use; this is an extreme low-G environment, & what we 'know' about cliffs etc totally missleading.

          • Prof Harvey Rutt says:

            The is a persistent tendency to misunderstand CONSERT and what it can and can't do.
            I re watched P34B-01 on CONSERT a by Kofman, and here is a summary. I previously posted links to CONSERT design and ice properties.
            CONSERT got good data during the descent, but was switched off some 40 minutes pre touch down to prevent interference with other instruments. The data confirmed accuracy of order a few metres. They saw some surface reflections, unanalysed as yet, which will provide some data on surface dielectric properties later.
            Occulting data, through the comet, was only received for c9 hours, part of one Rosetta orbit. For two sections of this, the signal was passing rather tangentially through the 'head' of the duck only; good signal to noise. For a longer period, it passed tangentially through the outer layers of the 'body', and tangentially through the 'head' poor signal to noise. 'In comet' path lengths were ~800-1000m.
            There is some evidence of multi-path propagation, as yet unanalysed in detail. (Several possible explanations, I could but won't speculate.) very little evidence of scattering; this is suggestive of the comet being fairly uniform on a few metre scale. With its 10MHz bandwidth, CONSERTND cannot say anything about finer scales.
            Nothing was said about fits to a material model; they really have so little data, fairly meaningless.
            In summary, CONSERT data to date tells us that, for a *very* limited range of signal paths, the interior appears rather uniform on a few metre scale. That's all.
            There appears to be nothing whatever inconsistent with the flight dynamics density. Indeed, if it were solid (rock or ice!) even from this data, conflict with the density data should have been obvious (propagation delays in-comet would be much longer due to the higher real part of the dielectric constant.) no such conflicts ct was mentioned.

          • Prof Harvey Rutt says:

            This is a very good summary of the dielectric properties issues for CONSERT:

        • Ian says:

          1. Sorry but according to the laws of physics pockets of volatile ice being exposed by sublimating ices is possible. It is even more possible if there is an impact from another body.
          Citation please for your assertion that sublimation was impossible at the distances for the 67P and Holmes flare ups.

          2. the measurements of density do not depend on the internal structure of any body. Measure the mass. Measure the volume. Divide mass by volume!
          The explanation for the measured density does depend on the internal structure of the body , e.g. a comet could be a fluffy surface with a harder core. Or the reverse.
          It would be totally ignorant to say that the interior of comet is solid rock because of the multiple methods by which their density has been measured, There will be dust and maybe even some rocks but certainly not solid rock.

          3. The scientific literature lacks observations of "electrical activity" on comet surfaces. Just do a search on ADS for 'electrical activity comet surface' and you get 53 abstracts containing no observations and a few theoretical papers.

          4. Yes - electrostatic clumping is an obvious hypothesis of several hypotheses.

          5. Ice was not directly detected ny MIDAS - it was indirectly detected as anyone who knows the density of comets can understand. The density means that comets are made of dust and ice. Detection of a hard layer is thus detection of a hard layer of dust and ice. It cannot be solid rock because the measured density of comets (~0.6 g/cc) is not that of solid rock (~3.0 g/cc). It is basic science that you cannot have a body of sold roc that has a density less than water. Thus “Philae has detected ice on 67P because that is the only physically possible option for a comet made up of dust and ices”.
          Of course someone could entertain a fantasy about a shell of solid rock under the dust on 67P!
          No further comment needed except to note that the many observations of comets that established their density happened BEFORE the Rosetta mission. Measuring the density of 67P is only a tiny part of the Rosetaa mission. The over 20 years (design, building and flight time) and over a billion euros have been spent to study a multitude of comet physics.

          6. There is no euphemism, THOMAS. There are features. Most were expected because we have seen them on other comets. Some were unexpected. If we had known about the strange shape of 67P before there would may have been an expectation of unexpected features. Even without that knowledge, the fact that Rosetta is a really close, detailed look at a comet leads to the expectation of unexpected features!
          In the real world most of the features of 67P have been seen before on Tempel 1, e.g. cliffs, craters, plains.
          The strange shape of 67P is possible responsible for one unexpected feature - the "dunes" on the neck. Here we have a sloping field of dust with what looks like a slippage causing corrugations or dunes. It is sloping because 67P is not a sphere - the neck is a region of lower gravity where the pull from the lobes is partially cancelled.
          This is not to do with any denial of the science that shows that comets are made of ice and dust.

          7. Sorry - you do not know that the data is still being analyzed, THOMAS?
          That is how science works. The data is gathered and then scientists analyze the data. This can take a long time. That explains the lack of "official information", i.e. papers from most of the Rosetta teams. Some early, easily analyzed data has been published - see below.

          8. Why not "Enthusiastic amateurs are free to look for Philae.”? Images are released every few weeks.

          9. In reality there is no "Kathrin Altwegg’s interpretation". There is a paper which has a long list of authors of whom Kathrin Altwegg is the corresponding author.

          67P/Churyumov-Gerasimenko, a Jupiter family comet with a high D/H ratio
          'The provenance of water and organic compounds on the Earth and other terrestrial planets has been discussed for a long time without reaching a consensus. One of the best means to distinguish between different scenarios is by determining the D/H ratios in the reservoirs for comets and the Earth’s oceans. Here we report the direct in situ measurement of the D/H ratio in the Jupiter family comet 67P/Churyumov-Gerasimenko by the ROSINA mass spectrometer aboard ESA’s Rosetta spacecraft, which is found to be (5.3 ± 0.7) × 10-4, that is, ~3 times the terrestrial value. Previous cometary measurements and our new finding suggest a wide range of D/H ratios in the water within Jupiter family objects and preclude the idea that this reservoir is solely composed of Earth ocean-like water."

          This paper precludes Jupiter family comets as the sole source of Earth's oceans. This leave asteroids and non-Jupiter family comets as possible sources.

          Wrong THOMAS. As person with a background in science I know how it works. I know that scientists gain fame by overthrowing existing theories. I now that scientists constantly test the established theories. I know that established theories that are not overthrown are constantly refined. I know that no competent scientist would be ignorant enough to come up with a theory that comets are solid rock because they know what the measured density of comets is.

  • Bill Harris says:

    Welcome back!

    I'm still chipping away at the Movie Mosaics-- I do it manually and it takes time...


  • THOMAS says:

    It is becoming increasingly clear that the dust-jets are invariably associated with the brightest surfaces of the comet. The has already been ample evidence of the jets issuing preferentially from the lighter neck region but in this image, we also see them shooting perpendicularly off the bright-looking plateaus topping the cliff formations at the top of the larger lobe (the plateaus which slope down to the right from the highest point).

    The jets are just as suggestive as ever of glow discharge activity focusing on whiter-looking surfaces. This hypothesis could easily be confirmed or refuted by the long-awaited OSIRIS images whose release (even to fellow mission scientists) has apparently been pushed back sine die. One increasingly wonders why...

    • Prof Harvey Rutt says:

      There is a very characteristic thing about glow discharges; they GLOW. They radiate obvious spectral signatures from the lines from the neutral atoms, ions, and bands from molecular species. That's why they are called glow discharges.
      Another characteristic thing about them is that they typically *do not* erode the electrodes; many devices (eg, many gas lasers) operate glow discharges for years without electrode damage - the ion energies are too low to sputter the electrodes other than very slowly. Typical of fairly low density discharges.
      DC glow discharges also require a conducting electrode to supply the current; is it not only made of rock, but some conducting rock? on an insulator it can only be fast pulsed, or RF driven; I wonder where the large RF generator hides?
      ED machining typically occurs at very high density, in arc-like discharges; indeed it's usually performed *under oil*!
      I wouldn't be particularly surprised if, on some occasions, small scale discharges do occur on the surface. But there isn't a shred of evidence in favour of it as a large scale erosive mechanism.

    • Ian says:

      Sorry THOMAS but that is wrong.
      The source of jets cannot be found from 2D images alone. Read and see that multiple images from different orientations are needed to trace jets to their source.
      "In this particular study, the jets were observed over one full comet rotation. “By tracking them from image to image, we reconstruct their three-dimensional structures and link them to specific areas on the nucleus, of which the morphology and composition is now being investigated,” explains OSIRIS scientist Jean-Baptiste Vincent from MPS."
      And do not be fooled by the brightness in this deliberately overexposed image on that blog!

      • Ian says:

        Whoops: That should be "The source of jets cannot be found from a single 2D image alone."

  • Haerwe says:

    Did I understand it right.
    You left us with a bounty of raw data and went on a 2 week vacation - leaving a One-Billion Euro Mission unguarded ?
    Where are the keys ?

  • Robin Sherman says:

    Good to have you back again Emily and a Happy New Year to you.

    Holger still keeping his cards close to his chest. Given the very small area that the flight dynamics and CONSERT teams managed to narrow down Philae's position to, I am surprised that she still could not be seen by OSIRIS.

    It is noticeable in this image how the terminator line is slowly creeping South and we are seeing more of the "Dark Side", especially on the big lobe. The equatorial areas seemed to be marked by huge numbers of exposed boulders and rubble, the Northern "Hemiduck" by "dusty" plains and craters and the Southern "Hemiduck" by bare material full of linear features and crevasses giving a more glacier surface appearance. I am guessing most of the looser surface material has already been lost during previous summer excursions close to the Sun.

  • David Christopher Lichteneger says:

    Happy new and eventfulofamazingscience year to all of you involved.
    totally unscientific remarque from me:
    can't help it, but this specific Picture looks like some skythian mummified horse head to me. in profile. with a beautifully tended mane.
    smiles from Vienna.

  • gary duby says:

    you people are soooo cool , rock on . . .

  • Wayne says:

    Welcome back to all!
    It seems like the last three weeks have bees 3 years.
    I was looking forward to hearing about the finding of Philae, but it wasn't to be.
    Here hoping it'll happen soon.

  • Haerwe says:

    (this is the third try to upload my comment)

    Robin, Holger is not quite so silent as it seems

    He has repeatedly talked to his local newspaper "Goettinger Tageblatt" about effort and results.

    I must accept that the Principal Investigator OSIRIS H.Sierks MPS prefers to inform his newspaper-reading neighbours
    prior to the international science community.

    - - - - - - - - -
    18.November 2014

    2.January 2015

    • THOMAS says:

      @ Haerwe

      "Robin, Holger is not quite so silent as it seems
      He has repeatedly talked to his local newspaper "Goettinger Tageblatt" about effort and results.
      I must accept that the Principal Investigator OSIRIS H.Sierks MPS prefers to inform his newspaper-reading neighbours prior to the international science community."

      Huh? You are perfectly free to accept this but why should the rest of us?

      I've just read the two articles you quote and he is absolutely silent in both of them about his reasons for withholding the essential images he possess both from the "international science community" and, more importantly, even from his own science colleagues in the different Rosetta instrument teams.

      BTW, even if he were communicating essential information in these articles (which he doesn't) why should his local readership take precedence over his own scientific Rosetta colleagues and, more generally, over the European taxpayers who have funded this mission and are still paying his salary?

  • Thomas says:

    Happy New Year Emily and to all space enthusiasts.
    I posted what I obtained for the Comet Movie on the so-called topic, but I think it will be more visible in this topic.
    So that's what I obtained after stitching all the 24 mosaics:

    I'm also working on a smoother movie, using a morphing software to interpolate frames between each mosaic:

  • logan says:

    Wish list for next Philae(s):

    Two landers.
    One trailing the other by time=1/2 Insertion Orbit Period.
    Very eccentric orbit insertion.
    Leading lander insert orbit clock wise.
    Trailing lander insert orbit counter clock wise.
    They are going to encounter at perihelion and aphelion.

    Once all checks and simulations rendered,
    Then -at perihelion- one lander fly-catch with a line the other (fly fishing).

    Mass difference between landers have to be established as to account for comet or asteroid rotation.

    Advantages: Significantly more landing mass. Low speed landing. Both landers can differ in instruments.

    • logan says:

      On keeping on with this dream:

      Trailing distance between landers not half but full orbit distances.

      Orbit planes slightly dephased to avoid risk of hitting each other.

  • Robin Sherman says:

    Presumably there are NAVCAM images taken on Dec 12th, 14th and 15th at a similar time to the OSIRIS images for Holger's Philae search. I was wondering Emily if you could make them available to search ourselves. As you know there are various amongst us who have toys and gizmos to scour the images, not to mention the time. Holger may not have conclusive proof, but I think we here are willing to accept a lesser degree of certainty to satisfy our curiosity.

  • Dave says:

    Hi Thomas happy new year,
    I had already written too much, so the eggs did not get a mention, very surreal though.

    • THOMAS says:

      Can't wait for them to hatch! Or for the dinosaurs to come home to roost...

      Happy (and enlightening) new year to you too, Dave, and to everyone else on the blog.

  • Birgit Hofmann says:

    Hello Rosetta-team, hello rosetta (and philae ?)

    Very nice to see you again !

  • Prof Harvey Rutt says:

    The other instrument rather overlooked is MIRO - perhaps because it produced no real 'surprise'.
    MIRO is a mm wave spectrometer; I can't find a free access technically detailed description, but this abstract tells you a bit:
    MIRO sees the rotational absorption lines of water (neutral H2O, completely unambiguously) for all three oxygen isotopes, and a few other small molecules such as CO and NH3. It can measure the line of sight density, and line of sight *velocity*, from Doppler data. This is unlike the mass spec measurements, which give the H/D ratio and a local point density.
    Thus MIRO a. Can tell you an awful lot about how much water is being produced from that data.
    Early results showed lots of neutral water; no surprises.

  • logan says:

    Hi Robin. Just seen a 3 camera system in an asymmetric arrangement. [software included] 🙂,28320.html

    • Robin Sherman says:

      Happy New Year Logan. I bet the science teams would have given an arm and a leg 15 years ago for that processor and memory too. It could run Rosetta and all the instruments as a background app. Satellites have been put into orbit using a smartphone as the on board processor. Might have to do a bit of work on the optics of those cameras though, the auto focus might have a bit of trouble at 30Km.

      Looks like revealing images of any sort are going to be in short supply until Valentines day. All we can look forward to is the slow unveiling of the "Dark Side".

  • Prof Harvey Rutt says:

    This gives more detail on MIRO.
    It can also get the line shape, which gives temperature via Doppler broadening done to c10K. It measures low J, vibrational ground state lines, so can still see very cold gas (expansion cooled until it goes essentially collision less.)
    The broad band channels will also give shallow sub surface temperatures, unlike the infrared instruments which give the surface itself. This should be helpful in understanding the temperature issues.
    These are crucial to understanding the jets.
    Because the 'downstream' pressure is so low, any 'reservoir' only needs to maintain a really very low pressure to get choked flow, a shock wave in the throat, and sonic exit speeds. If the heat flow to the walls of the interior 'chamber' (possibly many linked small volumes with high surface area) can provide the latent heat of evaporation, flow will continue. These issues are all linked. The structure will also determine the thermal conductivity to those internal ablating surfaces.
    MIRO a will be crucial to a complete understanding of what's going on.

    • Dave says:

      Hi Proff Harvey,

      We are all ears, it would be great to see some more data, especially anything that details the initiation of the jets and the evolution into long columns.
      Miro was one of the first to give exiting news ref the amount of water in the tail and the rate of production. They did express surprise back in September about the lack of Carbon monoxide in the tail
      It also gave us the first temperatures for light & dark side, possibly down to a depth of a few centimeters.

      At that time it was looking fwd to the night time fly by and comparison of its results with VITIS.

      Since then there has not been much and also in particular not much about the dark side in general.


      • Harvey says:

        Regarding the 'jets', whilst fluid dynamics is not my speciality, I think (like many things on 67P) it is extremely easy to be mislead by 'experience, common sense' etc. The conditions are simply wildly different from those we are used to.

        We are used to situations in which the flow is viscous, the mean free path minute (hundreds of pm at ~1 bar) and the gas density high enough to 'push around' dust etc in the flow. Thats what we *see* all the time, its how, inevitably, we interpret what we see.

        But on 67P, the pressure falls to very low values very rapidly as you move away from the surface. Mean free paths become very long, flow is molecular, and there will be no interaction between dust particles & the gas at small distances from the 'nozzle'; we have the biggest vacuum pump available - the Universe - reducing the pressure 🙂

        Yet another factor is that we preferentially see the larger dust particles in visible images; the bulk of the flow is neutral H2O which is invisible in visible light.

        So be very cautious about visual interpretation of the 'jets'. It needs proper modelling of the tricky viscous-to-molecular flow regime & its interaction with entrained dust to make sense of it.

  • masanori says:

    Welcome back Emily and all in the blog/comm team!! Hope all of you being healthy all through the new year and beyond!

    One thing I really would like to know.:

    How much the mission team need to know the location of Philae. If they need, why? By when? How much accurately? Etc. I can imagine it's for CONSERT data at least. And perhaps of course, the more Philae gets data about his current home the more the scientists love to know where it is. But I imagine there must be more reasons. So, hope the mission team explain about it somewhere one day, hopefully before long.

    • Harvey says:

      Masanori. I think the most important reason (aside from the obvious ones for CONSERT & engineering data) is summarised by 'context'.
      Philae provides detailed local data. But the terrain on 67P is very varied. To make sense of the 'local view' the lander provides, we need to known in what type of terrain it is sitting.
      For example, crudely, if your lander on earth saw for a few metres around it say sand, you would understand much better if you knew its on a beach or in desert dunes.
      You need the 'context' of local data.

  • Prof Harvey Rutt says:

    (Problems posting this; it says duplicate, but it hasn't appeared...can't see that it breaks the rules!)

    Regarding CONSERT.
    It is not really accurate to say it was 'designed to detect ice'. It was certainly designed with the likely presence of ice in mind, but in fact other constraints are probably more important.
    Details of CONSERT a can be found here
    And details of the properties of ice (there are many sources) for example here
    CONSERT a uses a 90MHz carrier with a 100nS code step. This step ultimately determines your spatial resolution, and forces you to use a high enough frequency to keep the fractional bandwidth reasonable. You are also constrained by the antenna size, and of course power, weight, cost.
    At 90MHz ice has fairly low loss - so you can hope to propagate through the comet - and the dielectric constant has fallen to values not that different from many other materials. All the 'ice signature' dielectric behaviour is at much lower frequencies - but then you wouldn't penetrate the comet due to loss, and could not get the resolution as the bandwidth would be too limited (and antennas problematic.)
    A two frequency instrument would have been great, but I'd assume power/weight/size costs prevented that; also it is a completely novel instrument, it's asking a lot.
    CONSERT is a clever, complex instrument. It's data will have to be tested against models to see what fits, what doesn't. The limited life of Philae means they got few paths for tomographic reconstruction, and little integration to improve the S/N. It's not going to produce some magic CAT x-ray like image of the insides of 67P, even if Philae wakes up, certainly not with the data the are likely to have got.
    Unlike OSIRIS! Where, like many, I think more could be and probably should be released, raw CONSERT. Data would be utterly useless to anyone here (including me.) it needs a great deal of effort to interpret it. The 'conspiracy theory' merchants will have a field day with it; the reality is it's the constraints of science, engineering, materials properties.

    • Dave says:

      Thanks Prof

      I have no conspiracy theories, clearly Consert has been hampered by Phillae, but a lot of the instruments overlap a bit, so I am surprised there is not a bit more information that helps get to the bottom of what the core is and how the jets work.
      Some release of Osiris pictures probably could help.


      • Prof Harvey Rutt says:

        Dave,marry the 'conspiracy theory' comment was not aimed at you; but there are those here who will interpret anything that doesn't fit their model that way - and I don't mean the 'Whipple-ites'. 🙂

        CONSERT really is the only instrument that can see the interior of the commet. MIRO a gets down just a few cm. the drill a little more. But CONSET is the only direct measurement of internal structure.

        OSIRIS images, which I also think they should release more off, are superb for topography etc. But for what goes on in the Jets, caution. OSIRIS a sees dust, but most of the degassing is H2O , invisible to OSIRIS. The low density means those two are not 'connected' in the same way they are here at one bar.

        • THOMAS says:

          @ Prof Harvey Rutt

          "OSIRIS images, which I also think they should release more off, are superb for topography etc."

          I'm not sure what you mean by "topography" but if you are using the most common sense of the term, the NAVCAM images released so far have already provided a lot of extroardinary and unexpected images of the comet. The OSIRIS images have a completely different function.

          What we expect from the OSIRIS images with their resolution going down to a few centimetres or millimetres, is not information about topography but information about the actual *matter* the comet is made of, especially the matter which looks identical to stratified rock formations observed on Earth and on Mars. Handed over to professional geologists, the close-up OSIRIS images should quickly reveal whether this rocky-looking matter is actually ice, rock (and if so, precisely which family or type of rock), carbon-based materials or something else.

          I remain confident, despite the current refusal by the OSIRIS team to open this treasure-chest even to their fellow ROSETTA team scientists, that the totality of these images will eventually be archived and released for wider analysis (if only as the result of an official FOI request) and that the truth about the surface composition of 67P will thus be unequivocally established one way or the other.

    • THOMAS says:

      Hi Prof,

      No conspiracy theory needed. The withholding of all those essential images by the OSIRIS team is clearly *not* a conspiracy, since it is reportedly infuriating their fellow Rosetta mission scientists themselves and clearly hampering their work.

      It is now generally admitted to be more a case of common or garden vying for maximum academic kudos. And who can blame them in a sense when those images represent a once-and-only chance of a lifetime? None of us ever have or ever will be in that sort of situation so it's difficult to know how we would react ourselves.

      • Ian says:

        Definitely not a conspiracy theory, THOMAS , because they tend to be secret!
        What we have is the well known and quite standard policy of giving the scientists who worked on an instrument a 6 month period of proprietary use of the data. It is actually generally admitted that this is a well known policy!
        There are people who want instant gratification and demand to get the data now.
        There are people with reasonable requests for more PR images.
        However the scientists in the Rosetta teams know about the policy and so should be satisfied with waiting a few more months..

  • Graham Hall says:

    So Dave, there's no ice on the comet. What therefore is the mechanism that produces water in the coma?

    admit it you're plain wrong. The ice is there along with a lot of other materials but in the top surfaces it has already sublimated. Deeper down - less than a foot / 30 cm there is ice, mixed with lots of other stuff. and its not only ice that is sublimating but carbon based molecules too.

    In British history Admiral Lord nelson is said to have said "I see no ships" while holding his telescope to his blind eye - you are the modern equivalent!

    • Dave says:

      Hi Graham,

      I am at the moment keeping an open mind, so far no ice has been detected on the surface, but the Consert experiment has not identified andy ice under the surface. It was specifically designed to identify ice and the structure of it in the core of the comet. That way we may have had some clues on the density.

      It may be that the data has not been released yet, or that Consert cannot work properly without the location Phillae.

      Until there is Data I will have an open mind, I suspect there is more than one process at work. Already ESA has mentioned likely sputtering from the comet, but I repeat lets wait for the data, I am not concerned either way with the outcome, but I would like to see the facts produced.

      Your opinion may be right but at the moment there is no evidence for what you believe.


      • Harvey says:

        See above; CONSERT *was not* 'specifically designed to identify ice' and it cannot do so.
        It can compare its data to trial models including, or excluding ice; but a single frequency measurement *cannot* 'identify ice' with certainty.
        Without a doubt having an extact location would help, but it should be quite possible to invert the data using a variety of points within the know area; the *exact* location, to the metre, should not matter that much given the 100nS PSK code. However they have few paths & limited integration due to Philae's short life (so far); dont expect too much.

        We already know the density with very high confidence; we already know water - as neutral H2O - pours out of 67P & other comets; its kind of difficult to explain it without ice. Though it does hide rather well 🙂

        • Dave says:

          Thanks Harvey,

          I seem to remember at the beginning of the project it was stated the range of the instrument was choosen so that it was sensitive to the expected ice, and so could be helpful to identify what kind of ice structure was in place.

          So 'specificically designed to detect ice' may be too strong a comment, but I believe finding ice was the consideration.

          I have tried to find the article to no avail

          Maybe we should change the poem.

          water water everywhere, but not a drop of ice


          • Prof Harvey Rutt says:

            CONSERT a can certainly 'detect ice' but not in the sense that it can give a specific 'this is ice not something else' result. The material has a complex dielectric constant, the real part primarily giving the delay, the imaginary part the loss. The problem is you are trying to reconstruct the interior when not only the distribution of the material, but both parts of the dielectric constant, are unknown. Two many variables.
            Down at very much lower frequencies, ice has a very clear 'signature', with the real part far higher than that of rock. But then the loss would be too high, no signal, the bandwidth too low, no resolution, and the antenna too big.
            CONSERT is a brilliant concept, and I'm sure it can deliver a lot, especially if Philae 'wakes up'; they need more paths. But I also think a lot of people expect more than it can possibly deliver.

  • Star Gazer says:

    Can these comments get moderation, please? The cranks with Electric Universe "beliefs" have hijacked the comments with LONG posts about paranoid nonsense. Considering that people read comment boards for a layperson's summary or to ask questions, this is hardly a service to ESA's audience to have electric universe CRANKS posting first always and with greatest rambling incoherently ".....plasma....density......those icy snowball scientists are thru.......!" People who are uninformed may read EU garbage comments and take them as evidence based scientific findings which they're not. Seriously, no one from ESA or the public for that matter bothers to post at cause its Crazy Town, so please moderate their presence away. They are free to submit their nonsense to any public journal and publish papers like everyone else. Why does the Rosetta board serve as an Electric Universe soapbox? Please moderate comments.

    • emily says:

      Hi Star Gazer
      Thanks for your comment. We try to be fair with our moderation and allow a range of ideas to be discussed, but I agree that the most appropriate place for lengthy EU theory discussion is indeed (or other equivalent forums). The purpose of the Rosetta blog is to provide updates on the Rosetta mission and to share images and scientific results when available. We expect the discussion to be based on this information and to remain on-topic and not be used every time to post exactly the same comments. (This was what I was trying to get across with the blog house rules earlier this week We will be closely monitoring the concerns raised in your comment.
      Best wishes for 2015

      • Sovereign Slave says:

        Rule 2 for posting: "Please use respectful language when responding to other comments. If you disagree with something, that’s fine, but any comments that are considered aggressive or unnecessarily rude will not be published. Constructive criticism is welcome!"

        Star Gazer's comments BY FAR have been the most aggressive and unnecessarily rude I've ever seen on this blog, and even resort to name calling of all things. Odd that you should use it to make your point about following the blog comment rules. But just for clarity, it's apparently now ok to call other commenters paranoid cranks and their comments nonsense and garbage and crazy and to demand that their comments be moderated away if we don't like them?

    • THOMAS says:

      Hi Star Gazer! I couldn't agree with you more!

      Posts from "cranks" who say "rambling, incoherent" things like ".....plasma....density......those icy snowball scientists are thru.......!" certainly should be moderated off the blog. Since I haven’t seen any yet, though, perhaps they already have. In that case, well done, Moderators!

      I believe (as I have consistently tried to demonstrate by my own example) that posts should be consistently evidence-based, thoroughly reasoned, fully cogent, invariably on topic, impeccably referenced where required and unfailingly courteous. These requirements are particularly important in longer posts. Posts should, above all, NEVER contain gratuitous insults or paranoid ranting. I’m sure the Moderators are particularly vigilant on this point, since very few of them have ever got through.

      I’m confident that we can all live up to this sort of standard.

      The only point on which I would disagree with you slightly is on the question of freedom of expression. As long as the above requirements are met, I honestly do not see where the danger is in allowing the expression of alternative ideas to the existing paradigm. Quite the contrary! There are famous examples in the history of science which conclusively prove the benefits of dissident observations, notably that of Galileo’s telescope which ultimately produced the paradigm shift from a geocentric to a heliocentric cosmology but which the Establishment scientists/ecclesiastics of the time adamantly refused to look through.

    • logan says:

      Hi Star Gazer. Have seen very interesting observations and ideas from you. Happy to see you around.
      'Hijacked': That word have technical tampering implications; and haven't seen that.
      'LONG posts': You are right, having myself problems with them due to slight dyslexia. But have been asked here to conglomerate my heterogeneous wanderings and wondering in just one post, so to be easily jumped over. Considering appropriate within "Rosetta in 2015", some people summarized their 2014 personal [in]sights, I suppose.
      'Considering that people read comment boards': Silence -ontologically- is not an answer. Commentary and chat is -of course- neither science, and people visiting people's boards is or soon become aware of it.
      'Cranks, Paranoid nonsense, Crazy Town, Soapbox': Truly appreciate your warm words, even if I am not an EU fan. On differing, some other people would go around with a cold, quiet and self-sufficient overlook.
      Asking Emily to moderate you would amount to censure.

  • emily says:

    Some of our more active commenters seem to have already forgotten the rules highlighted in the first post of 2015!
    We will not be approving any further comments that talk disrespectfully about scientists ‘patching’ data or falsifying it in any way to suit one theory or another.
    Science and scientific peer review can be a lengthy process. Conclusions cannot simply be made overnight. Data need to be collected over a certain time period (be it weeks, months or even years) to be able to draw statistically meaningful conclusions. Papers covering the wide range of questions asked on this blog regarding various aspects of the nature of Comet 67P/C-G simply haven’t been published yet – but they will be, and we are all looking forward to seeing the results.

    • Harvey says:

      I wholheartedly agree with these comments.
      The posts imputing malfeasance are completely out of order & deserve blocking.
      I also agree the EU stuff is nonsense; as I've tried to point out many times.
      The problem of course is if its completely blocked, they just go off to some self-reinforcing clique site like Thunderbolts, & never actually get exposed to reality.
      So there is in my view a somewhat tricky path between a 'block nonsense' approach, - which in many ways might suit those of us involved in more serious science better - & a more open, 'they should have their say' view.
      At least then they do get exposed to rebuttals & just maybe some understand why its nonsense; though some never will!
      I dont envy you your moderating task Emily, rather no-win Im afraid. Perhaps this post istelf should be judged off topic! -but a reasonded discuussion of moderating policy seems valid.
      I think, personally, I would certainly block the downright objectional & the more ridiculously rambling, repetitive stuff, but allow the rest. The 'serious' community can ignore it, or try & explain, if we can be bothered.

  • Dave says:


    Re a lot of stuff,
    Sorry I missed your blog but as Thomas has answered your points anyway I won't address them all over again.
    Thomas thanks for the reply to Ian, I could not of answered it better.

  • Ken says:

    It's 2015 and still no sign of Philae... With the lack of information from the project (info that's not scientifically sensitive so I don't understand the blackout), it's hard to tell what progress has been made with trajectories / bounce reconstruction etc, so I'll provide some thoughts. The folks over at the planetary society unmanned spaceflight forum have been active in this area (I fully credit them for the inspiration), and a recent series of posts yielded a find of 3 moving objects and/or shadows shortly after the first bounce: (see link for the picts). Kudos to them (particularly Deepnet and mcgyver) and their tenacity!

    My take on that post was the left two objects were a kicked up rock and it's shadow, but the object on the right has no associated shadow so I think it's Philae's shadow as it's bigger and changes geometry consistent with a spinning lander.

    Anyways using another unmanned blog post for look angles (thanks Brian Lynch)

    one can make a trajectory and ground track that fits the possible Philae shadow. I have made a very simple geometric fit in the following figure (ignore the blue lines which are old assumptions). The red oval is the possible Philae groundtrack, green is Rosetta OSIRUS picture look angles, yellow is sun angles and purple oval is Philae's potential shadow ground track. The yellow star is the point of the OSIRIS picture showing Philae and the red star is the other presumably later (from the movement of the right 2 objects/shadows) OSIRIS picture showing the possible Philae shadow. The blue stars are corresponding actual Philae positions if you were overhead looking directly down on it.

    The takeaway is I think Philae actually went very high and double backed westwards (i.e. completely opposite the current assumptions) and is in a completely different spot then the project is looking at.

    If the project isn't doing a detailed trajectory reconstruction scenarios, I urge them to at least give the amateur community key data sets (times of all pictures would be a great start) so they can run the numbers - it's in everyone's interest to find out where Philae ended up ASAP while Rosetta can still get in close and take confirmation pictures.

  • Bill Harris says:

    Thank you Emily, for your sometimes seemingly thankless task!


  • Andrew R Brown says:

    Thank You very much and very Happy New Year Emily.

    Thank You for moderating me as I do need moderating at times and I had a blip with my medication, trying to keep a cold down can cause me to 'blow my top' at times as already explained a while back during a previous, my worse spell.

    I support Star Gazer 100% with the comment that there are plenty of avenues for the Electric Universe Hoax to be channelled through perfectly legitimately.

    Back on topic Emily, I suspect the darkened Winter side of the comet should soon be starting to get some low oblique sunlight, would be a good time to get some observations in before it warms up.

    Still think this observation is absolutely incredible.

    Do you if Dr Alan Stern PI of the New Horizons Pluto spacecraft has seen this? Reason why I ask is that much of the darkened Winter hemisphere of Pluto will be imaged using reflected sunlight of a gibbous Charon just after closest approach. If Pluto has an extended 'atmosphere' some sunlight may also stray over the terminator. This Rosetta observation certainly validates that methology.

    Andrew R Brown

  • emily says:

    Dear all,
    Many thanks for the feedback on the subject of moderation, and apologies for the delay in approving the comments. Since it is in itself a rather subjective discussion that could go on forever, I’ll wrap it up here by repeating my thanks to you for helping to make this a respectful community, with plenty of interesting discussion to be had during another exciting year for the Rosetta mission!
    Best wishes,

  • Grant Dexter says:

    This guy could have made the predictions. In fact, he did.
    PREDICTION 37: Most of the rocks (pebble-size and larger) comprising asteroids and comets will be found to be rounded to some degree. (This rounding occurred as the rocks tumbled and were eroded in the powerful fountains of the great deep.)

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