CometWatch – 28 October

This four-image NAVCAM montage comprises images taken on 28 October – shortly before moving to the pre-lander delivery orbit – from a distance of 9.7 km from the centre of comet 67P/C-G, or roughly 7.7 km from the surface.

The corresponding image scale is about 65 cm/pixel, so each 1024 x 1024 pixel frame is about 665 m across. The montage has been slightly tweaked and the central vignetting reduced. The four original frames are provided at the end of the post.

Four-image NAVCAM montage comprising images taken on 28 October. Credits: ESA/Rosetta/NAVCAM

Four-image NAVCAM montage comprising images taken on 28 October. Credits: ESA/Rosetta/NAVCAM

The montage nicely ‘joins the dots’ with the region presented in the  8 October montage.

Given the peculiar low-density, low-gravity nature of a comet, it is perhaps dangerous to make direct analogies with Earth-like features and processes. But until we have the science team’s analysis of what they think is actually happening on this comet, analogies might nevertheless still provide a useful way of trying to decipher what we are seeing.

In a number of places in this region, there is an impression that the prevalent dusty material covering the surface is not particularly stable and that it occasionally gives way, perhaps in a similar way that snow on a mountain side may become dislodged, giving rise to an avalanche or, alternatively, a rockfall or landslide. For example, look in the lower third of the top left image. There you’ll see what looks like a crack close to the edge of the cliff, suggesting that this portion might eventually collapse, similar to the way a snow cornice on a mountain ridge peels away. This feature is also visible in the 8 October image.

Another example can be seen in the lower right corner of the bottom right image, where material appears to have slid over the edge of a cliff.

On Earth, avalanches are typically triggered by an increased load, leading to the mechanical failure of a slab of material under gravity, or due to melting snow as a result of increased solar radiation. On a comet, presumably the latter process is more likely to occur, with sublimation-based erosion acting to weaken the surface material, resulting in a collapse.

 

 

ESA_Rosetta_NAVCAM_141028_D

ESA_Rosetta_NAVCAM_141028_B

ESA_Rosetta_NAVCAM_141028_AESA_Rosetta_NAVCAM_141028_C

Comments

137 Comments

  • daposter says:

    snow, yes: when I looked at the landing sites some time ago I thought about it looking like powder, and what if the lander sinks in it without 'feeling' it is already under the surface.

    thinking of snow like consistency (gravity scales!), where snow flakes might not be grown crystals but blobs and chains of dust grains, as they formed when that astronout shook salt (or was it sugar) in weightlessness):

    some pixel locations in the 'D' frame that I think looks like very loosely deosited dust, sometimes perturbed, slid 'down', and the breaking edge walking back upwards a distance (like runs on a nyon):

    285,488 to 369,602
    around 251,416
    110,792, if it were snow looks like something fell from the cliff 'above' and cause a tear in the surface down to more dense layers on which it was sliding,
    549,998 and right to it looks like tears of different age,
    772,802, the triangle of the feature mentioned in the blog, looks like a 'walk backwards up' of the perturbation front and it has been deposited and not slid further (and compacted through that action),
    862,815 through 874,860, wonder where 'down' is, probably towards some place between the lobes when 'standing' at this location
    and most important to me, maybe to all of us after the 12th: 713,501 looks like an impact into the powder, leaving nothing and not even opening to the 'bottom' of the layer. That might be all Rosetta will see of it once the lander has 'touched down'...

    very nice this blog entry reminded me of the nicrogravity of the environment
    at any location the gravitational pull must be very interesting, it is a weak dipolar field, where the gravitational pull of features near to someone 'standing' there would significantly alter the field.
    Imaging this on earth: you drive next to a high mountain and your car is pulled sideways towards it....

  • Jacob nielsen says:

    Oh yeah! These are great! They are great, but not as great as Holgers.

  • logan says:

    The 'dry pasta' fields.

    Leaving that to the 'classics' to explain 😉

    http://blogs.esa.int/rosetta/files/2014/10/ESA_Rosetta_NAVCAM_141028_B.jpg

  • Rod Jenkins says:

    We are not looking at a mountain side where the gravity gradient is down the slope and avalanches can occur. I assume that the gravitational force is approximately vertical at each point of the surface. I guess that it is the influence of the other lobe that gives a smaller horizontal component. If the surface is undermined then the surface may collapse with some spreading across the surface as the surface layer breaks up. Would like to see a plot of the gravitational vectors and the correlation with the surface features seen.
    Little sign on this image of where jets may emanate from. Does so much surface dust imply that many sublimation streams are not that violent?

    • logan says:

      Hi Rod. Sorry but differ a little on this. The equatorial planes are horizontal to gravity. Don't think it's the same for the 'pasta fields'. Specially about the right 'ridge' of them. As you, believe that 67P is to small for 'mountains'.

      • logan says:

        As you, suppose that most of sublimation is by 'transpiration'. This idea ask for a continuous destruction / reconstruction of 'transpiring' structures at the sublimation line or, 'transpiring' structures strong enough to support the upper weight of sun 'toasted' material without their ice 'filling'. Other ideas welcomed. 🙂

        • logan says:

          Maybe 'drawings' are the more 'macro' of 'transpiring' structures.

        • logan says:

          One more scenario: 'Drawings' are the result of the 'inter-play' between the subjacent honey-comb/layer-comb and big surface dust/ice accretion/crystallizations. (As suggested to me by this particular mosaic).

  • Sajid Rabbani says:

    Although the main topic here is Comet 67P, but can the high-tech instruments and Cameras installed in Rosetta show some activity/images of any other comet or star or galaxy nearby.
    Well it could be some few thousand kilometers to few million kms away from 67p , but it would be interesting to know if there are some neighbors of this comet

  • daposter says:

    ... just spilled some flour: the 'boulders' that happened look similar to the 'boulders' on the comet....
    snow is made by disk shaped units that can glue together, forming a stiff bond
    flour is made of dust, held together electrostatically, of chains of small starch grains (maizena) or fragments of grain bodies (milled), the electrostatic holding together is not really stiff, chains of grains can move

    is philae beeing sent into a 3 meters plus layer of very losely deposited flour like dust with no gas in it, so no 'resistance' from the displacement of gast between the dust grains and grain aggregates ... chosing a 'flat' surface may turn out to have been a bad decision: it's not a 'surface' but the top of a dust layer with density pretty much 'zero', going down to 'compacted' with densities maybe 'a little bit better than zero'.....

    • Jacob nielsen says:

      @daposter, well put and this is one worry you share with a number of us in here.

    • logan says:

      Hi Daposter. 'Fluffy' dust has a very particular infrared signature. And OSIRIS can look directly at it.

  • Bill says:

    Ah, connect the dots, eh?

    Rotate today's montage 90 deg clockwise, it fits to the lower right of the 8 Oct montage. The scree (rubble) deposit in the upper left is the match point.

    I agree with the "light snowfall" analogy of the "draping deposit" -- in terms of texture, density and cohesiveness this may be a close match. Much as the "fairy castle" model of the lunar surface was in the 60's . Google "fairy castle lunar" for more.

    https://www.hq.nasa.gov/alsj/Fcastles.htm

    for starts.

    --Bill

    • Jacob nielsen says:

      Maybe the 'fairy castle' fits comets like this one much better than it did our moon? Yes, snowfall, and very light, but it would be something like 'uncombusted ashes', instead of a winter wonderland. 67p is a horrible cinder, an excrement of creation, a sorry leftover. I like our blue planet 🙂

    • Bill says:

      And if you want a little more info on the "landslides" and behavior of the "draped deposit" we see here, Google "slope stability" and dig in to that can of worms..

      --Bill

  • logan says:

    Perceive slight mind warping 😉

  • PAK2 says:

    A few weeks ago I mentioned the fact that gravity forces at the surfaces would be highly dependent on location over a shape like this, particularly in the "neck" region. Gravity is very weak, but the variations might still have some effect on observable processes. It would be interesting if someone could post ballpark estimates of gravity (magnitude and direction) over the surface of the comet. The landing team probably has detailed estimates of the near-comet gravity field, but nothing has been posted.

  • logan says:

    This mosaic seems to suggest that reducing insolation increases 'drawing' intensity.

  • logan says:

    Remains of Anubis sphinx filling most of top right quadrant 😉

  • Leo Vuyk says:

    It seems to be obvious that the icy rocks breaking their summits to produce boulders

  • Robin Sherman says:

    The average comet gravity is about 1/10,000th that of Earth. Phylae weighs 1 gramme on the surface, thats about 330 milliNewtons of force for each foot when landing at 1m/s. Can we make an estimate for the cohesive force of the surface layer? The edges of cliffs have slipped and left a pretty clean edge showing it can at least support its own weight in a layer about 1m thick. We postulate that the dust is made of mineral and silicate grains, which have an average density of about 3000Kg/m^3. If the powder is 2/3 empty space then we have an average density of 1000 Kg/m^3. A 1 metre layer of surface can support 1000Kg/m^2 or a force of 100 milliNewtons. Phylae's suspension system is designed to absorb a large proportion of the landing force, she will barely make a dent. Phylae's weight will compress the dust a little and increase it's density, by closing the spaces, further increasing the strength of the surface.

    Ok there are a lot of assumptions and approximations, but we see even a rough ball park figure tells us Phylae will not drown in dust. If slowly sublimated gases are percolating through the surface layer some will condense and freeze on the dust grains, increasing the density and cohesion. Think water below the surface of a dry sandy beach. The top few millimetres of sand insulate the lower layers from the sun and so a couple of millimetres below the surface, the sand is damp and wet, a couple of millimetres below that. We have speculated the Laktrtz layer is highly insulating, so ices may be just below the surface. Phylae will be fine as long as she doesn't land on a boulder or a steep slope.

    Now onto the "drawings" on the surface. We have vast tracts of it to examine in this image. The swirly, bumpy, lumpy surface, is different in detail, but over large areas looks much the same apart from slight differences in shading. Where the Laktritz has slipped off the edge of a cliff, we see the icy sub surface layer below. It displays the same pattern of dents, pits, scars and ridges. So as suspected the surface layer just reflects the subsurface layer beneath. This then moves the question onto how does this appearance appear on the subsurface all over the comet?

    A common and simple mechanism surely. Slow sublimation of the subsurface ice layer must be the conclusion. The result is a surface that appears quite similar to sublimating and ablating ice surfaces on Earth. We see what small amounts of sublimation look like, little potholes, semi circular valleys and linear scars, so we can surely extrapolate to what more rapid sublimation would look like on exposed material.

    Look at the top of Cheops, little depressions and linear scars. Take a large area of exposed material and we see the same things, except the potholes can get quite a lot bigger, semicircles deeper with steeper sides and the scars deeper. Deep enough to cause ice fracturing and cliff collapses. Small chunks are seen with little holes and pots in them, scars and semicircular depressions. Linear scarring seems to be the most common feature, making all sorts of interesting shapes and patterns.

    Now mechanisms to explain each of these different features is a whole different ball game. Material composition and porosity, mixing of different materials, variable amounts of dust and organics within the ice, exposure time and angle of incidence of the Sun, crystal defects all of which must have an influence on what shapes are left behind. The oddest I found in this image is the top right of Image C on the head lobe. Some, what look like, scaffolding poles just above a shape that looks like a waterwheel. To cap it all a river of dust runs just below it. It must surely be called "The Mill" feature.

    Below The Mill and just to the right of the lower of the two large lumps on the horizon, guess who? Yep Bob the Builder and he is waving to Rosetta too. A couple of "Dune" worms too for Logan, one top middle Image D and one on the very edge of the body lobe, middle of Image C.

    Finally the view of that awesome cliff under the head lobe. You get a real sense of the scale and its shear surface. Move over El Capitan, this is a couple of hundred metres taller and made of sheet ice. Could probably jump right to the top though with minimal effort in this gravity. Might be tricky aiming to take into account the gravity variations on the way up, and avoiding going into orbit would also complicate things.

    Copies of the fully illustrated book to accompany this series is available at all good book retailers. 🙂

    • Robin Sherman says:

      I hope those calculations are right, its 30 years since I did any Physics.

    • Ross says:

      Be careful using the calculated densities and masses of the comet. If electrostatic repulsion occurs between Rosetta and 67P, imagine how much lower the density would be perceived to be. When Philae lands and reveals the nucleus to be a solid body, what will scientists think about the calculated density then?

      • logan says:

        A week at 10km. If relevant geometric differences between both forces exist then it should be noted and considered by now. Remember those big 'ground' cables external to ISS and make me nervous, more than the very slight dynamics worry.

    • logan says:

      Worms are good in a healthy gut 😉

    • THOMAS says:

      @ Robin Sherman: "this is a couple of hundred metres taller and made of sheet ice".

      No, Robin, according to the ESA experts, there is no visible ice anywhere on the surface. What we see under the cliff lobe is a shear cliff-face made of vertically stratified rock, as is in this famous early picture : http://blogs.esa.int/rosetta/2014/08/14/comet-67pc-g-in-3d/

      No ice, just stratified rock.

  • Neil says:

    Let me express a comment about the flat areas (whatever they are made of). I do a lot of diving in the lakes/pools/puddles of underwater springs. Recently, I have been in the Te Waikoropupū Springs also called Pupu Springs in Golden Bay. Bear with me in my analogy and then shoot it to pieces. Water upwells from below pushing the sand up in patches several metres square and then that sand settles nearby for the heavy bits and further away for the less heavy bits. In many places, there are no distinct vents just diffuse areas of “boiling” sand. What I see on the comet is flat areas that look very similar to the result of the lifting and settling of sand in the bottom of the spring. The water pressure in the pool immediately above the sand compared to the under the sand would be very similar. I am picking the comet vacuum pressure at the surface of the flat areas is very similar to the vacuum pressure under the flat areas. On the comet it is the sublimation pressure that potentially uplifts the material of the flat areas, in the same way that water comes up through the sand in the bottom of the spring.
    Question: Do the high res images of which we have seen so few show a gradient of grain size over the flat areas?

    • logan says:

      🙂 Just add Clive's 'rumbles' proper of sites like this as a triggering mechanism.

      • logan says:

        High Res not public yet. Vibration takes bigger chunks up.
        (Just shake your coffee jar, as an example). So finer dust down. Trapped by capillarity organics create the seal at bottom.

        • logan says:

          On displacement, the seal breaks, then we have a massive gas leak along the fail.

          • Robin Sherman says:

            Given the very low gravity and the fine nature of the dust I guess it would not take a very large amplitude of vibration to instigate this settling. Add to that, the natural compression of lower layers by the weight of the upper layers, the porosity would decrease the deeper into the Laktritz you look. Exactly this was seen with the fine dust on the moon. Add to this the "Fairy Castle" model of jagged rough surfaces on the dust particles, physically and chemically binding the dust together, add in some Van de Waals forces, the Laktritz layer might be even more resilient than snow, the mineral grains won't break like snow crystals.

            Also reassuring for Phylae, is the surface dust layer does not appear to be that deep, maybe a couple of metres or so. The Lunar dust was well over 10 metres deep and Astronauts exerting orders of magnitude more force than Phylae will, sunk only a cm or two into it. The rubble on the surface of 67P does not seem to sink into the dusty plains, even Cheops with its large mass, hasn't sunk into the dust.

            As to whether the bottom of the surface layer is compact enough to make a seal, I doubt. The sublimation even at a very minimal rate would keep "stirring the pot" and Chromatography columns show, even silica particles of 5 microns jammed together by pressures exceeding 300 x atmospheric pressure, are still permeable to fluids.

    • Robin Sherman says:

      Hi Neil. I think your analogy is very relevant. The surface layer is so porous I see no reason why there is a difference in pressure, the vacuum, between the top of the surface layer and the bottom. The sublimation pressure is less, but the particles of the surface layer have a negligible mass in the low gravity and are shown to be movable by the sublimation pressure large distances. Evidence, the plumes creating the dusty haze enveloping the comet. Found this video on You Tube which shows what you are describing. Absolutely amazing place by the way.

      https://www.youtube.com/watch?v=dRbQ9GRh9C0

      • JP says:

        Actually,
        I see a reason for the pressure to vary with depth, one way or the other:
        Within the dust layer, the number of gas particles will remain rather constant, like a flow of outgassing with a subsurface source; once the gas reaches the surface, given the mean free path (very low pressure), the gas particles will very quickly escape, i.e. particle density (and pressure) drops dramatically.
        At each contact with a dust grain, the gas molecule will reach close-to-thermal equilibrium: the closer to the surface, the hotter the dust, the larger the pressure. So I expect a pressure profile close to exponential (=temperature profile) up to very close to the surface, where it drops very quickly (over few mm, a few tens of dust particles diameter).

    • Bill says:

      Yes indeed. "Sand boils" are one thing that comes immediately to mind _in certain terrains_. We've not seen anything like that _yet_, but we haven't had access to the hi-rez OSIRIS imagery, and the comet activity is low, but on the increase.

      I'll suspect that we will see that soon.

      --Bill

    • Ross says:

      The problem is that the jets are collimated and confined, thus requiring a nozzle-like vent. In the method you're describing, the sublimation would just subtly "leak" from the surface and likely would not be visible. Comparing processes on the comet with phenomena on earth will likely lead you into a dead end of refuting observations.

      Whatever mechanism is producing the jets must explain why the jets are collimated, why they are sourced from terraces and scarps, why vents are not found at their source, why they lead to obvious erosion, and how they can lead to hydroxyl and water production in the coma. Cathodic etching of the surface releases oxygen which bonds with hydrogen of the solar wind and wahlah! You've got everything we need, no sublimation required.

      • logan says:

        Hi Ross. In my mind 'jetting' an collimating are separated phenomena.

    • logan says:

      Still a pair of years to go into 'search and destroy' mode 🙂

    • logan says:

      But you are right Neil, Gas 'washing' should do the same as liquid washing, taking farther away those particles which expose more surface area. Nowadays, why the 'burping' focus at some 'line' of points? At those sites occur a 'sealing' layer formed by 'plaque' biota.

      • Jacob Nielsen says:

        biota?

        • logan says:

          Sorry Jacob, did not say this particular argument is about Golden Bay. You are the biologist. I'm just talking about bio-film acting as a gas seal.

          • Jacob nielsen says:

            No need to be sorry 🙂 I just find it hard sometimes to track your 'stream of consciousness'. I really like your tireless attempts! Bacteria on 67p would be a crazy idea, but still an inspiring one. The sorry thing: I think over the last days, maybe as some sort of function of the pace of new information (no new info), the zombie virus tries to spread.

  • Kamal Lodaya says:

    From the posting on 3 October we know that the comet's density is 0.4 grams/cubic cm. The nuclei of other comets (Halley, Borrelly) have also been estimated as having density figures in the same ballpark. What are reasonable models which yield these densities for the overall objects? The kind of substances on Earth which have these kind of densities are peat soils and manure. It seems difficult to imagine that this comet is made of such porous substances all the way down to its core. If we suppose a frozen hydrocarbon or hydroxyl core, its density would be between 0.6 and 1 gram per cubic cm. Would a lighter porous soil surrounding such a core yield the desired figure of 0.4?

  • Kamal Lodaya says:

    Missed Allenbe's posting and the subsequent discussion on the 0.4 figure in Cometwatch-26 October.

    • logan says:

      Hi Kamal. Welcome again to the 'state of the chat'.

    • Alembe says:

      @ Kamal Ladoya and Daposter - You are welcome!

      It seems from the discussion above that more people are coming to terms with the low density of P67 and the implication that its bulk structure must be porous, potentially friable and very dusty/powdery.

      I just hope that Robin Sherman's calculations are correct and/or there there is enough of a surface crust to support Philae upon landing.

      • logan says:

        Robin and me think that precisely this nature makes 67P resilient 🙂

    • John says:

      Kamal, density of the comet is a crucial issue and certainly deserves continued discussion. It is worth saying again here that a highly plausible theory exists relating mass (and therefore density) to state of electric charge. That is, mass is dependent on charge. The same volume of any particular material could accordingly have different masses in different charge states. The densities of materials therefore that we are familiar with on Earth would not be applicable to other charge states in other regions of the heliosphere, such as where the comet is. The fact that the obviously rocky comet returns a measured density of only 0.4 g/cc strongly suggests that this might be the case. It should also be noted that if there is even a possibility that the charge/mass relationship applies any analytical method which works by measurement of deflected particle mass ( ie. mass spectrography) would not be reliable, and could well be meaningless at the location of the comet, using instruments calibrated on Earth.

      • Alembe says:

        John,

        In the context of the discussion on this blog, I would be considered a mainstream scientist. As such, I accept the accumulated data that the laws of mathematics, physics and chemistry are universal. If they were not universal, then the Flight Dynamics Team at ESA would not have been able to drive Rosetta through 6.5 billion kilometers of space with several planetary assists and deliver it with exquisite precision into orbit around P67. This awesome feat demonstrates the robustness of their theory, science and execution. Thus when this same team determines a mass, and subsequently a density, for P67, I can see no valid scientific reason to question that.

        The interesting part has been starting with this P67 density of 0.4 g/cm^3 plus the known densities of its component molecules and minerals, and then considering the implications for the bulk structure of P67. It was this logical thought process (using Mainstream science) that led me to propose a porous/friable/powdery structure for P67.

        • Robin Sherman says:

          A porous structure was the immediate conclusion of the ESA team on arrival day. What we have to remember is that with so little gravity around the structural strength of the material making up 67P does not have to be very great at all, so a lightweight "honeycomb" internal structure surrounded by the more solid crust as an exoskeleton would be more than enough to maintain the shape of the comet. Using a lightweight honeycomb structure covered in a lightweight "skin", is an established engineering solution to give structural strength and rigidity using less and lighter weight materials.

          There were many experiments carried out, indeed ideas for huge aircraft carriers, on a material made of 14% sawdust mixed with water and frozen, called "Pykrete" during WW2. Pykrete is exceptionally strong structurally and resists fracturing vastly more than normal ice. The ices on 67P being mixed with mineral dust and organics, I should think would be considerably stronger than the pure ices too. No doubt there is experimental evidence to show this, and by how much.

          • Robin Sherman says:

            Maybe 67P is actually made of Pykrete Logan and the woodworms have indeed been eating away at the sawdust to create the neck. 🙂

          • logan says:

            Like these arguments 🙂

        • John says:

          Alembe, I do not question the density figure, just what it means. Neither do I question the excellence of the technology in the design and navigation. However the fact that the comet exhibits a density of 0.4g/cc is a huge and startling anomaly when it is clearly a rock structure. A good scientist whether mainstream or not would be deeply interested in this and consider all the explanations. One would be that perhaps there is something we do not know about density and which requires serious investigation and perhaps we should be circumspect about density figures until we can explain it. Another would be that the comet is made of fluffy dust. To pick the fluffy one and move on is not science. It is jumping on the first superficial conclusion that comes to mind and failing to dismiss it as absurd. Still, we do not yet know what the Rosetta scientists think as they have yet to comment on the issue. Hopefully they are still thinking hard.

          • Denis says:

            A good scientist whether mainstream or not would be deeply interested in this and consider all the explanations, starting by the most likely. Deducing that the laws of physic are incorrect and/or varying with the position in the solar system is certainly not the most likely; especially as we have already sent probes all over the place (many of them including instruments dedicated to measuring plasma and electric fields).

            As for a rock of low density, check out "pumice" on wikipedia, there is a nice picture of a rock (which does look like rock with a density of 0.25 g/cm^3, i.e. almost half of 67P).

            Yes, I know, it's a volcanic rock and clearly 67P did not form like that.
            However, it formed by accretion of materials and it seems very plausible that it could result in a low density materials, given the low gravity which cannot lead to much compression of the materials.

            I think there are overall a lot of possible explanations, all much more likely than having to reconsider the laws of physics.

  • NavCam October 28
    Composite image draped over HD shapemodel.

    mono: http://youtu.be/40vJvruqoKs

    anaglyph: http://youtu.be/yQtNf1WYPdM

    3DTV http://youtu.be/cucKRXnM5f0

    • John says:

      OK Denis what a good scientist would do is a matter of opinion perhaps and yours is different from mine. It is not a question of abandoning the laws of physics. It is about considering that there may some aspects of physical behaviour not covered by those laws and which we are not aware of. We are after all dealing with the close study of a comet, which has never been done before. The laws of physics are by no means complete. What the force of gravity is and how it is transmitted is for example unexplained in mainstream physics. Rather a basic thing.
      And yes plasma and electric currents have been detected in association with solar system bodies including the Sun, Earth, Venus, Mars, Jupiter and Saturn, always greeted with surprise and without any explanation, in the mainstream, of why electric current should be there at all in system of bodies supposedly isolated from each other apart from the effects of gravity.
      Pumice type rocks are formed because of gas evolution during solidification from high temperature which creates a honeycomb of trapped bubbles. Even for a pumice 0.25 is an exceptionally low density. And for a rock pumice is exceptionally low density anyway. But you do not believe this comet was formed by solidification so it is unreasonable to invoke that type of structure as an explanation of its low density. Also accretion as a means of forming large bodies from small particles has never been plausibly explained or modeled, for any density let alone densities of 0.4. It is just an idea.

      There are of course several possible explanations for the surprisingly low density and it is an intriguing puzzle. No reason to pick one at this stage even if it is thought more likely. This judgement depends on knowledge and how complete it is, also on the analytical data more of which should be available soon. More surprises I expect.

  • logan says:

    The 'after party' tell us a lot of what is going to happen in the next perihelion.

  • Cometstalker says:

    Instead of the navcam resolution images that are 85*85 micro radians per pixel it would be on time to release an Osiris 19*19 micro radian per pixel resolution image. The surface would look a lot different when seen at a 20 time better detail recognition. There must be a logic reason that the public presented images are limited to a resolution >1/4m^2 at the best when <1/60m^2 are available with enhanced detail recognition due to the color filter set in the Osiris NAC.

    I suppose there is no snow at all on the surface, it is another process and the relative smooth areas are very old, possibly the oldest features on this comet. The new parts are the boulders and rumble fields and those features are supported quite well on the smooth layers. The comet has changed its shape a lot in all those billions of years of its existence and the hardest part is to grasp this huge time scale. The landslide, avalanche and winter sport area properties noted are not a proper description of any processes on the comet. Our Moon might be a billion or more years younger then the comet and its surface as seen today is a lot younger still, the dust was sampled and is quite well known, nothing did sink deep into it due to a lot of reasons. Comets are most likely the oldest lumps in our solar system and to try to compare its creation with features that happened last week to last decade on a hillside on Earth is quite naive. How many avalanches has been noted on the Moon from its very steep quite high mountains during our observation in time? The gravity on the Moon is relativ high and a few parsons did walk on the Moon. Do calculate how long it takes for a pebble to reach the surface if dropped from a one meter altitude and do the same calculation again for earth like gravity, then realize what a so called land slide is all about on the comet. Also take the Coriolis force effect into your calculation and imagine what a land slide on this comet would look like.

    • logan says:

      Intriguing toughs Cometstalker. To me there is a titanic conundrum: On one side is this acceptance of comets as something really Old. On the other side is this initial public data, showing us an incredibly Cold and -at the same time- Dynamic object.

  • logan says:

    Hi Robin. On bringing up to date your reference to

    http://www.esa.int/spaceinimages/Images/2014/10/Comet_on_2_October_NavCam

    I would like to bring a 'visual allegory':

    Looks to me as if wood mites have eaten some 'central' soft layers and left the hard layers at both sides of the neck. (Just to stimulate creativity) 🙂

  • Sovereign Slave says:

    While we all are obviously extremely excited about the Rosetta mission and love speculating on what P67 is and what it’s doing (thanks Emily!) based on scant evidence, in the ongoing absence of solid scientific data, the blog discussions almost seem to be taking on the dimensions of a cosmic snipe hunt. In fact, I’m getting the feeling we’re starting to beat a dead rubber ducky while waiting for the necessary scientific updates to meaningfully advance the discussion - and no Robin, I don’t think P67 is REALLY a rubber ducky, even though it does look like one 🙂

    So in the meantime, I would like to add to the discussion one important point that each theory advocated here (Electric Universe (EU) vs Mainstream) do have in common. Each theory relies on SCALABILTY to explain cosmic phenomena.

    Now, Mainstream astronomy’s most basic tenant is that the force of gravity interacting with matter accounts for the vast majority of phenomenon observed in space. However, there is an obvious problem with gravity when it comes to accounting for the huge forces observed in the universe – gravity is an extremely (extremely!) weak force. And those that study space know that there is no way that what is scientifically known and verified about gravity in the “everyday natural world” can account for it exerting the tremendous forces needed to create the massive energetic phenomenon found in space. So, what to do? How to solve this dilemma?

    Enter scalability. In order to match the strength of the powerful forces observed in space, we’ll need to increase the force of gravity. Hmm, but how? Well, as Einstein said, “Imagination is more important than knowledge. For knowledge is limited to all we now know and understand, while imagination embraces the entire world, and all there ever will be to know and understand.”

    So, let’s start IMAGINING how to solve this dilemma. Now we know that gravity seems to increase with mass, but in order to really explain things using gravity, we’re going to need a lot of mass, way beyond what we KNOW about mass in the “natural” world. In fact, we’ll need infinite, “supernatural” mass! So, what can we IMAGINE could explain infinite, supernatural mass? Well, perhaps one way of increasing mass would be to condense it. But we all know you can only condense it so far before atomic and other forces counterbalance it and make it impossible to condense any further. Well, even though we’ve never observed this ever happening in the history of mankind, let’s IMAGINE that a large enough object could maybe collapse down onto itself to the point where it violates everything we currently know about atoms and it crushes the bajeebies out of them to the point where they no longer exist and the matter becomes a different state of being that’s now got infinite mass and provides the necessary gravity to start making stuff happen on a cosmic scale. So, though it violates scientifically validated physics, we now have what we’re going to call a black hole for our tool box to pull out any time we want to explain things. And as long as we’re using our imaginations so well and are violating known physics anyway, let’s throw in dark matter as well because of that pesky (and speculative) expansion thing, oh, and it’s looking like we need to come up with something we’re going to call dark energy as well. And even though no one has ever seen this stuff, or encountered it in the natural world, we’re going to spend billions and billions of dollars supporting its research and promoting it and trying to prove it’s true. And on and on the countless snipe hunts go.

    Now, EU theory also bases its arguments on scalability to explain phenomena in space, as well as on earth. But the difference is that electrical scalability was not created in the imagination, it was revealed through rigorous scientific method. It’s based on what we know and understand (sorry Einstein). In fact, you might say that the ultimate test of whether something has been subjected to the most extreme rigors of the scientific method is if it has become an applied science or not. Electrical scalability is not only a proven phenomenon, it is exhibited and used as a basis for everyday life (applied applications, something that appears to be lacking with black holes and their imaginary friends).

    There are countless relatively weak electrical interactions occurring everywhere, within our own body, within the earth, in the sky. You can then scale it up to the stronger electricity running through your house, through power lines, on up to lightening bolts and beyond. There’s absolutely no doubt that electricity is scalable (again, unlike gravity beyond it’s “natural” occurances), and it’s everywhere here on earth. Why then, when it comes to the study of space, is it assumed that electricity and its effect is confined to earth and its atmosphere, and does not extend in small through large scales throughout space? We KNOW that electricity is scalable, and we KNOW that electricity can create radiation for instance, and that the greater the electrical force, the more radiation generated. Why can it not then explain the large scale radiation events found in space that exhibit many other electrical properties as well? We do NOT know that black holes exist, or can actually even generate any radiation whatsoever even if they did exist.

    EU scientists observe phenomena in space that look and behave in identical ways to electric phenomena observed in nature, or recreated in the lab, or utilized in everyday modern life. They utilize known phenomena to explain observations without violating other known and scientifically validated phenomena or principles. They also accurately predict phenomena in space that continually seem to surprise the Mainstream (how many times do we have to keep hearing how surprised the Mainstream is with each new discovery?), who then inevitably retreat back to their imaginations to come up with yet more new theories.

    Anyway, I agree with Einstein, imagination is a wonderful thing, but it seems to have become an addiction that has hijacked the study of space while speeding us further and further light years away from what we actually do know and understand.

    • Cometstalker says:

      Gravity is weak only because the normal matter is diluted by nothing. If one kilogram of mass is theoretically compacted to its full then this kilogram is smaller than an atom, or if planet earth is compacted to its maximum it would have the size of a pebble. In those cases gravity is the strongest of forces. Relativistic singularities are created by gravity because all the other forces can not withstand it as soon as the amount of mass and density becomes high enough.

      Forces from electric charges are essential if there is a low density environment. Although i have no idea how it plays a role on an intergalactic scale.

      Gravity is not always to be seen as a force between two bodies or particles. Gravity is the curvature of spacetime and i do not mean the rubber sheet demonstrations.

      • Ross says:

        That is wrong, gravity is the force which is explained by the curvature of space, but there is no reason given why mass would curve space. The forces inside the atom on the smallest scales are without any doubt electrical in nature, so why assume that gravity is most significant on larger scales? Had Faraday, Birkeland, Tesla, Maxwell and other pioneers of electricity has seen what we can observe today, the standard picture would be very different.

        I believe that Rosetta will lead to undeniable evidence of electrical processes responsible for the cometary phenomena. My only worry is that this discovery would end there, without further investigation of similar mechanisms among other astrophysical observations.

        • Denis says:

          On large scales, gravity dominates electric forces because observations show that the universe is mostly neutral, i.e. it is mostly made up of the same amount of negative and positive charges (when know that because we can deduce it from observations as light interact with charges). As a result, the electrical forces cancel each other on large scales.

          On the other hand, we have never seen anything with negative energy density and therefore gravity is always attractive and does not cancel out on large scales => even if it is the weakest of the 4 existing forces, it always add up to generates large forces which dominate the structure we see on large scales.

      • Sovereign Slave says:

        Well, there may actually be a third alternative in the works, Cometstalker. As I’ve said, I keep up with both Mainstream and EU theory, and there’s a theory related to gravity gaining ground in mainstream because it may actually better explain what’s been recently encountered in space study. It proposes that exploding stars and other violent phenomena can actually cause rifts within both space/time AND matter, and that within the vacuum of space, these phenomenon can basically “dislodge” and expand the orbital radius of elements within atoms. So in effect, this makes the normal weak force of gravity many many orders of magnitudes greater related to this matter, which has much much less density than “normal.” They’re even calling it “white” matter since it is basically the opposite of dark matter. The thing that’s fascinating to me about it is that ANY “normal” force will have absolutely huge effects on it, hence explaining many of the massive events witnessed in space. It also appears that when white atoms interplay with normal atoms, they tend to cause the normal atoms to also expand their orbits (harmonic orbital synthesis). One of the reasons this theory is gaining ground so quickly is that it effectively explains why the universe is expanding so quickly. More time and funding is needed, but they’re saying this theory may actually dethrone black hole theory...Now, having said all that, I must apologize for quickly developing and penning my own imaginative theory, but I just couldn’t resist. I bet I had you going though.

        • Robin Sherman says:

          Hi SS. Like that! Gravity distorts and stretches spacetime. For every action there is an equal and opposite reaction. I am not aware of any theory explaining where this stored "elastic energy" if you will, of spacetime, manifests itself. Gravity is over time concentrating matter and the stretching of spacetime is increasing. Some property inherent to spacetime is being reduced as it stretches, its resistance to expansion say. Could this be what allows inflation, the acceleration of the universe's expansion or increases the space within atoms to maintain equilibrium. The carrier of this force would be Rob's Boson and I'm sure the next Ultra Large Hadron Collider would be able to find it. The Higg's Boson must have a partner, symmetry demands it.

    • John says:

      Sovereign Slave, It is quite valid to question and argue the assumptions that are made and the beliefs that are held before the data is available. That is what is happening here.

    • Denis says:

      Sorry to say that, but you are slightly mistaken about what you call "mainsteam theory".

      Black holes are certainly not needed to explain structures seen on large scale.

      For example, there is no need to have a large black hole in the middle of the galaxy, a galaxy without black hole would behave exactly the same way as with one. The mass of all the stars are enough to hold the galaxy together (for example, the mass of the black hole in the center of our galaxy is believed to account for something like 0.0004% the mass of "normal" matter in our galaxy).

      Black holes have been imagined when trying to understand what happen when a heavy star dies, as we know that small ones end up in white dwarfs which we can observed (maintained by electron degeneracy pressure), medium ones in neutron stars (maintained by neutron degeneracy pressure) and then... ? no other phenomena is known that could prevent the collapse until what we call a black hole (which we cannot see directly but we can see it's influence on the surrounding environment).

      On the other hand, it's true that there are strong anomalies which lead to believe there is "dark matter", i.e. matter which has an gravitational influence (i.e. it has an impact on the rotation speed in galaxies and it bends light).

      However, it's not clear how EU solves the problem. For example, it will hit the same problem with the galaxy rotation rate anomaly (because both electricity and gravity are 1/r^2 laws, they behave in the same way) and therefore some non-visible matter must also be there in the EU theory which is even more problematic because electric charges directly interact with light are are easier to detect that diffuse matter which don't interact with anything except by having a mass.

      • John says:

        Denis, why believe in black holes and neutron stars because you have been told they exist. There is no evidence without assumptions that you can point to. Effects that have been held to demonstrate the presence of a black hole, such as at the Milky Way galactic core, can be explained by other means. A singularity, an infinitely small dimensionless point, effectively does not exist. It is just a mathematical concept arising from division by infinity and could not have any gravitational effect in reality. An example of theory without limits.

        So too with the neutron star. It is an idea that was dreamed up by one individual to justify the existence of pulsars with speeds of rotation too high to be sustained by normal matter. There is no evidence that atomic structures could be compressed so that all the electrons combined with the nuclear protons leaving just densely packed neutrons. Such a structure would, according to established theory of atomic physics, be impossibly unstable at any scale. There is anyway no need for pulsars to be perceived as rotating at thousands of revolutions a second. The pulsation can be readily explained by an established electrical phenomenon.

        Dark matter too. Another concept that has never been detected in reality because conveniently, by definition it cannot be. No time here to talk about the imagined expansion of the universe and misinterpretation of red shift data. However the apparent galactic rotational speed anomaly you refer to can be easily explained. A galaxy is effectively a huge homopolar electric motor and in the same way that the angular speed of the disk of such a motor is the same at any radius, so too with the galactic disc.

        Once you realise that everything is connected by a vast network of plasma filaments carrying huge electric currents, all of which can be readily detected there is no need for imaginary concepts like neutron stars, black holes, dark matter, dark energy, dark flow and a big bang.
        Perhaps one apparently impossible dream might be acceptable in a cosmological theory but not all impossible dreams.

  • Robin Sherman says:

    The left side of this mosaic is the equator area of the big lobe. I discussed how I thought this was a huge fracture in the surface caused by the gravity of the head lobe squashing the body lobe. From the perspective of this image it not only is it fractured, but the surface has collapsed big style as if the material beneath it has been taken away. Whole plates of material have fallen into the chasm and the field of dry pasta, the result of a catastrophic collapse of the cliff as the surface sank away into the beep trench.

    We know the density of the comet overall is low, akin to a powder rather than a solid and the surface looks basically like a continuous solid. A large amount of the mass of the comet is actually found in the surface, meaning inside the comet there is a lot of empty space and a very porous material filled either with gases or vacuum. The resistance to motion through this material must be pretty low, more like a low density fluid. Solid lumps of denser materials can migrate through this material under the influence of gravity and the forces created by the spin of the comet. Over time the denser more solid material would collect at the bottom of the body lobe and some would be pulled towards the head side of the body, leaving little in the way of solid material to support the crust. Result, collapse of the crust. The same mechanism as I think created the trench we call the neck, only at an earlier stage of its evolution.

    All that jagged, tumbled and broken crust material has lost a lot of its insulating layer of Laktirtz and is prone to more rapid erosion by sublimation. The icy crust material in that case will eventually sublime away leaving a new layer of Laktritz, the non volatile dust and organics that had been trapped in the ice, and a deep trench looking like the neck area.

    The results from CONSERT are going to be really interesting, but they do require Phylae to land safely and operate long enough to get the data. With two spacecraft crashes in the last week the omens are not good. These things do tend to come in threes. Still China's spacecraft round the Moon mission worked just fine as did the Russian supply run to ISS, so maybe she will the third successful space mission. Fingers crossed for Phylae.

    • logan says:

      Could you add ion migration to your migration schema?

      • Robin Sherman says:

        Yup no problem. There are bound to be a lot of dust, static electricity and charged particles present in the spaces inside the comet. Migration of particles along the lattice/honeycomb structure would be something very likely I would think., attracted to, or repelled from, the Solar Wind and Cosmic Ray charged surface. Any good?

    • Kamal Lodaya says:

      Robin: Regarding your statement "A large amount of the mass of the comet is actually found in the surface, meaning inside the comet there is a lot of empty space and a very porous material filled either with gases or vacuum."

      What prevents the surface mass from falling in? Aren't you then postulating an interior full of energy? Whereas if we postulate an icy structure inside, its heating up and sublimation accounts for occasional falling in and creation of trenches on the surface, without need for any other energy source. I don't yet see a good reason to choose between the two models and iceballs seem more economical.

      Before Rosetta reached 67P, around April the coma went through an outburst: http://sci.esa.int/rosetta/54071-rosettas-target-comet-is-becoming-active/ Is there a good hypothesis, in light of what we have seen of the comet now, for what could have caused this? Could it have been a trench collapse? Which one?

      We had the gross data on the comet in the posting on 3rd October. It would be interesting to know if any of the parameters have been sharpened over one month.

      • logan says:

        Hi Kamal, on your comment:
        "... the coma went through an outburst..."

        My personal first toughs are about tides triggering tectonics, then thermodynamics triggering pressurization/depressurization then a slight chance of electro-dynamics.

      • Robin Sherman says:

        Hi Kamal. We have an average density for the comet of about 0.4g/cm^3. As Alembe explained the likely materials having such a low density would be powders or very porous solids. Powders have a low density because much of the volume they occupy is actually the space between the grains of the powder. We can see that the surface of 67P is made of a pretty condensed solid, be that rock or ice and is patently not a powder. It could be a pumice like material, with lots of tiny spaces in it that we have no hope of seeing with the resolution of NAVCAM or even OSIRIS. That solid looking crust would still have a density greater than 0.4. This means the material inside the comet, say a few hundred metres below the crust, would have to have a density of less than 0.4.

        As you surmise there must be something with sufficient structural strength, holding the surface in place. A low density powder by itself could not do that.

        A porous honeycomb lattice of denser ices and occasional bits of solid rock could make up the lattice with a powder made of gas, dust, ice and organics filling the spaces. The comet is like a giant Malteaser in effect. A continuous solid layer on the surface with a honeycomb centre. The powdery component would behave much like a fluid and allow the migration of more solid and dense material through it. Dense materials making up the lattice might be displaced and areas of the surface collapse.

        I am not at all sure this is actually the case, but given the low density it is a scenario that could explain it. Hopefully next week the Rosetta science team might outline their theories to explain the low density and the apparently solid crust.

        Some time ago I did suggest a reason for the April/May outburst. The volatile ices collected on the comets surface as it travelled along the cold part of it's orbit through the zodiacal cloud, would at some point in its approach to the Sun, receive enough energy to sublimate from the surface. Little or no ice was detected on the surface of 67P by Rosetta a couple of months later. Something of a surprise at the time, as was the higher temperature of the surface. Perhaps enough heat was retained in the porous, insulating Laktritz layer from the previous close approach to the Sun, to allow this sublimation at a point further away from the Sun that might have been expected.

        Since that time we have had the appearance of the bright jets and the idea they are produced by tidal stresses in the comet. I wouldn't know the details, but this flareup could be when the tidal influence of Jupiter and the Sun interacted in someway to stimulate increased activity in the neck area, or the Sun's gravitational influence at around that point became greater than Jupiter's, with the same result. Neither theory has much in the way of facts to back them up, but are just my best guesses. Not a simple problem obviously, since 6 months later we still don't have even a preliminary explanation from ESA.

      • Kamal Lodaya says:

        Robin: Thank you for the detailed explanation, I now see what you mean. I had to look up what a malteser was since I have never seen one. Do caves with stalactites and stalagmites provide a reasonable analogy? Do we have some theories about how they form?

  • logan says:

    Easter Egg for the 'jet' searchers:

    Almost horizontal 'jet' action signature. The dusted+eroded zone follow a beautiful 'drop' form.

    Location: Near bottom border of top right quadrant.

    Pixel 1553,876 of

    http://www.esa.int/var/esa/storage/images/esa_multimedia/images/2014/10/comet_on_28_october_navcam/15011477-1-eng-GB/Comet_on_28_October_NavCam.jpg

    • logan says:

      Does that give an idea of the 'ethereal' nature of 67P?

      • Leo Vuyk says:

        Hi Logan,

        You seem to be good in pixel count.
        Could you estimate the diameters of the average snow bubble dunes visible all over the snow surfaces?

        • Leo Vuyk says:

          FOR MORE CLAIRITY Logan, the snow surface resembles a chicken skin with small regular bubbles.quastion : what could be the diameter of these bubbles.

          • logan says:

            Hi Leo. Just using a small photo editor saying at what point I am. Around here it the matrix base of the 'drawings' is estimated around 1 meter.

    • Robin Sherman says:

      If that is an "Easter Egg" this must amount to a big "Christmas" present. Image D 785,785, a small boulder of ice with a bright top has sprayed fresh bright material in a jet/plume 15 to 20 metres long across the surface. No zoom required and its definitely not picture noise.

      http://blogs.esa.int/rosetta/files/2014/10/ESA_Rosetta_NAVCAM_141028_D.jpg

      • logan says:

        Copy. 11 o'clock angle, then it extends slight at 10 o'clock angle 🙂

      • THOMAS says:

        Robin, according to the ESA experts, there is no ice whatever on the surface, let alone "boulders of ice" (or "ice-cliffs", which you refer to elsewhere in this blog). Your steadfast insistence on seeing ice where others (including the experts) only see rocks and rock-faces is starting to seem irrational.

      • Leo Vuyk says:

        I only observe an avelange of the snowy surface in the middle of the photo into the direction 4 o'clock

  • Peter says:

    Coupé you please place a bar or a stroke onto the surface of 67P to show the length of e.g. 100 metres? Would help a lot.

    • Robin Sherman says:

      Peter. Each of the four separate images are about 665 metres square. A ruler and a calculator can be used to find the size of any object or feature. I for one prefer the fantastic beauty and awesomeness of these pictures unsullied by scale bars and text. We have been given so few images to pour over, hiding some crucial clue under a scale bar would upset a great number of us.

      A BIG thank you to Emily and ESA for not doing so.

  • Dave says:

    Thanks for some ideas ESA, but what sublimation?
    AND what ice, so far you have not admitted that you have found any of these.
    The erosion is clearly electric and is destroying the scarps so that there are landslides.
    The dust is being lifted due to the electrical activity .
    You can measure the magnetic fields.
    Where is the sublimation? In areas under the jets the dust has all gone and there are no holes visable that could blow away the dust. There is no surface sublimation, because you tell us no surface ice.
    There are no vents visable on the ground from underneath the jets. The only other surface process we know to generate water, other volotiles and silicates as dust partials is electrical erosion.

    There can be no other way unless there is something you are not telling us

  • Atom Universe says:

    What is the surface temperature of philae? Is it same as that of the surface temperature of 67P/C-G?

  • Atom Universe says:

    There may be some low melting point substance (in frozen state) which may present beneath the rocky (just an assumption) surface.

    These substance got melted and expands through the porous regions and flows over the rocky surface and got frozen, when it moves away from perihelion.

    • Atom Universe says:

      Some of the previous Images, shows these frozen substance (which I assume) to be dust particles.

  • dave says:

    If there is no Ice on the surface (even ESA admits that there is no surface ice), then there can be no surface sunblimation.

    If there is ice under the surface we need vent holes or very porus rock for it to escape.
    If its vents, then we would of seen them, several pictures have faint jets where we can see the ground beneath,. In these shots the dust has been blown away leaving the rocky surface. NO vent holes though. this leaves 2 alternatives.
    1 If the rocky surface (ITS NOT ICE! ESA cannot find ice on the surface) is porous then the supposed sub surface ice could filter out like hot gas through lava leaving a pumice type structure. If this was happening we might see some disturbance of the dust that was covering the surface, but i dont think we would see whole ground clearance like we are seeing, the gas could just perculate through the dust. Also this would leave no method to form the highly ordered columns of jets that stay that way for great distances, the gases from sublimation would just spread out into the vacumm.

    2 The other way which has been demonstrated in a lab at NASA back in the 70s, is the electrical scouring the surface. This breaks down the molecules at the suface and eats away the surface, proviiding water, other volatiles and silicates in the coma. These have been observed by ESA from spectral analysis and from dust capture.
    The electrical break down of the surface is what we can see happening right now, the results so far shown by esa are consistant with this.
    This then gives a way for the columns to form, because where there is current flowing and there is! There will be associated electro magnetic fiels (basic physics) its these fields that order the jets into columns.

    I can not see any other way to describe the information and photos we have.
    If you look at Birklands work then you will see how these columns can form, ordered by the charged particals coming from the sun and generating thier own containing electromagnet field.

    • Denis says:

      I can see how solar wind could interact with the surface to slowly erode it, however, it's not clear to me what you mechanism for the "jets" of matter: some current of charged dust/particles? But a current between the comet and what ? The solar wind? But the solar wind is mostly neutral (made up of both protons and electrons), it's not really clear what exactly you are suggesting here.

  • dave says:

    cometstalker,

    The electric effects on a galactic scale are already in plain sight!

    The advances in telescopes of all types make it possible to see whats ggoing on!
    - Just look at our Sun, specificlly the close ups of the sun spots, you can actually see the paired Birkeland currents very easily. The consequences of this is huge so people shy away (ie no neuclear core)

    -whats more if you look at the pictures of the Galaxies you will see filaments between the areas of star formation, there is no black matter or energy behind these, they are simply Birkeland currents powerering up the stars. Again people shy away from this, god knows why because the current std model alternative, is that we are asked to believe that what we see when we look up is only 3% of the universe, the rest of it is invisable to us in the form of dark energy or dark matter, and the list of dark things we have to accept is getting longer.

    There was a rediculous Horizon programme on a few weeks ago postulating something like Dark curved space, all proffesors interviewed for the show admitted that they did not even know what it was, inccredible, literally.

    - So when we get to super novas, the ability of our telescopes to clearly show the form/shape of whats happening, they confirm scalable lab experiment. These structures require no black holes, the plasma forms are truly scalable. But ofcource because to admit the truth black holes have to be abandoned along with an awful lot more of the current scientific thinking

    Have a look the structure of the universe it is clearly visable whats happening, but its electric just like the sub atomic particals that are in everthing we can see touch and smell.
    More important its in plain site!

    • AndreH says:

      I am not to familair with the EU theory. But very obviously the orbital mechanics for all probes since the early days of Sputnik seems to work.
      The calculation of that orbital mechanics is based on gravitational interactions between the bodies of our solar system. So if rocket scientists get this all correct, is it just an coincidence and would EU deliver the same (if rocket scientists are obviously ignorant of it)?
      If the sun and the Earth are attracting each other, and the Earth and the moon are attracting each other how does it come we can calculate tides correctly by assuming an only attractive Gravitational force?
      How can we be attracted by the Earth if we are standing on it and are therfore on the same electrical potential?
      How can Cassini orbit Saturn and still feel attraction by its moons? The moons and Saturn must have opposite charges they cannot both attract the space probe.
      Wouldn't be any space probe landing on an other body immediately burn away in a gigantic arc?
      And why does a possible falsification of the "dirty snow ball" theory implicate that the solar system is not governed by an always attracting gravitational force?

      • John says:

        Yes Andre, it is not impossible that the rocket scientists could navigate spacecraft gravitationally whilst ignorant of the electric currents flowing and as you say they have done it. Although now they know that both the Pioneer craft were out of their projected positions by tens of thousands of kilometres by the time they reached the edge of the heliosphere slowed down by interaction with the current from the Sun in addition to the expected gravitational force.
        Nobody is suggesting that gravity does not exist. It it just an extremely weak force compared to the electric force but in the solar system it is clearly significant probably because of the huge masses of the bodies involved.
        The tides are predicted by observing what happens repeatedly and again no need to know what the relative influences of gravity and electricity are, provided they are acting together.

        We are held gravitationally on the Earth. When we are standing on the Earth we are effectively part of it and at the same potential, with bare feet. Otherwise there is a very small potential which is not significantly attractive or repulsive. That is my understanding anyway.
        As for the planets and moons it is the relative charge that creates the potential. They don't have to be opposite.
        If a lander approaches another solar system body slowly enough there is time for slow equalisation of charge therefore no potential when it touches down. ie the Mars landers. If it approaches fast enough there could be a very high potential and an intense discharge ie the copper projectile fired at comet Tempel 1.
        And if 67P is not a subliming dirty snowball the jets are produced by other effects one of which could be electric discharge(confirmed by other measurements). This would suggest that there could be an electric force operating in the solar system from which the comet picked up its charge. There is still gravity and one or other need not be dominant. They could be working together.

    • Cometstalker says:

      In diluted matter electrical forces are significant for sure, just relate what is going on at Cern. All matter that is accelerated in their experiments are charged ions, nothing else would work. Although the charge does not increase while accelerating, it is the mass that increases when the energy is elevated. Then new matter with electric charges are created due to the colission discharge.
      Also it is not a proper model to see space and time separated. In our perspective we do so because our senses are not capable to see the whole of it, we prefer to se a 3D environment and add a tick-tack to this. Spacetime is always there as a unit, its expansion and curvature is affected by mass and energy that is even outside our event horizon.
      Dark matter and dark energy is in my point of view not existing.
      All we know of our universe is due to measurements of electromagnetic waves and a few other forces and so far nobody measured the distance to far out objects with a ruler. We only make estimations and models and think it fits the bill until better and more accurate instruments are denting older models, but its still nothing but a model.
      Its the same for the micro cosmos, if LHC or whatever a lot of electromagnetism is going on in our experimental gadgets and the alchemists making models and guessing a lot usually forget a lot of parameters. Nature never forgets anything.
      The word black hole is one of those very poor models of events that from our point of view are grey shells or relativistic singularities. Snowballs in space is the same alchemistic tale and the list of small lies for the public is very long.
      We will not learn much from this mission other then that our curiosity is the only reason that is keeping us going on doing this kind of experiments.

    • John says:

      Horizon is effectively mainstream propaganda, Dave, and what can be expected other than the transmission of deluded fantasy (paid for by the public). You are right about how self evident the electric current conducting plasma nature of the universe is. The theory has a beautiful and unifying simplicity at all scales and there is no room for, or need for concepts like black holes, dark matter, dark energy, and neutron stars or a fusion core in the Sun, or the idea that the shift of spectral lines towards the red end is related to speed of recession and therefore distance. No room or need therefore for the big bang or inflation. All of these are ridiculous flights of imagination with no connection to reality. Similarly the meaningless concept of space-time. Embarrassingly they are however collectively the basis of mainstream cosmology and astrophysics so the EU paradigm is just too big a pill for mainstream academia to swallow. Because as you say everything is in plain sight many of the individuals involved must by now know they are barking up the wrong tree but it appears that they are interested in things other than the truth so the consensus is maintained. It is becoming increasingly difficult to sustain it though and a proper analysis of comet 67P and its behaviour and environment will add to that difficulty.

      • AndreH says:

        @John: you say "Similarly the meaningless concept of space-time"
        John, the concept of space times leeds to a theory that can be falsified very easily because it makes predictions galore about results of experiments and things which can be observed by simply using your eyes and maybe a telescope or allike. (movement of mercures perihelion, light coming from stars being bent by the mass of our sun during an eclipse. And there are some more.
        A lot of very sceptocal physicists tried to falsify that theory at least in the first 30 - 40 years. They all failed and at that time there was no mainstream establishment defending the theory. In fact that theory was at that time challenging the mainstream.
        It became accepted because it gets predictions correct and can be tested. It never has failed any test so far.
        Do you claim that all the outcome of this experiments was faked? Why should that have been done back at that time?. A lot of physicists would have been happy to proof Einstein wrong.
        Again is it your claim that there is a big conspiration going faking experimental results? And again, why should that have happened in the first place when Relativity wa "non mainstream"?
        Yes cosmology has a problem at the moment and is desperately seeking for solutions. This might as well include a correction of Einsteins relativity in some way. But however the correction is, it has to account for all the correct results predicted by it.
        Looking at the EU, I don't even see how it gets the orbital mechanics of our solar system correct. Even Newton had it almost right by a very simple assumption of an attracting force being proportional to the mass of the bodies involved.
        Go to the lab and use styrol balls hanging on thin threads and see if you can make two of them atracting each other and have a third one beeing attracted by both of them by chrging them.
        All you need is a glass bar, a rubber bar, some fabric to rub them, three styrol balls and some fishing cord.
        I personally prefer to stay with a theory which at least explains everything correctly on the "small" scale of our solar system than one that cannot even explain that correctly.

        Many times it was claimed above that "we see a rock, no ice". I agree we do not see ice as we know it from frozen lakes or ice cubes. But honestly, I do not see a "rock". I see a big chunk with features looking like rocks, other features looking like an agglomeration of boulders (with no evdence what those are made of), and big "planes" looking like they could consist of sand, dust, or whatever.....

        Coming back to the "dirty snowball" theory. I find it allways intersting that if a scientist tries to coin a word understandable for everyone he is taking literally decades later and people are lile " ha, now we got him, it is not a snowball therefore we know he was just a government paid mainstreamer to delute us an by the way this proofs Einstein was wrong".
        If he would have said: "I belive comets are an agglomeration of mineralic and volatile constituents where H2O is a major component" the very same people would have bashed him as an "theoretical guy paid by the government who does not know about the real world and uses science babble to confuse us ordinary people so government can delute us and by the way Einstein was wrong".

        I have said it before: I do not see how a falsification of the dirty snowball theory would shatter cosmology. In this case it will only tell us GP67 is not a dirty snowball!
        Maybe there are 5 different types of comets? Or 100 hundred? Or only one nad they are just different from what we thought?
        And no, I am not working for any government, and no I do not believe in big conspiracies hiding knowledge from the public (which can at least partially tested easily by anyone) and are going on since Kopernikus.

        Enough said. Hope Philiae will make it and deliver good data!

        • Robin Sherman says:

          With you all the way there Andre. Well said. Thank You.

        • John says:

          Thank you Andre for your detailed and considered reply. I am not implying any conspiracy from the beginning. More a misinterpretation and delusion that has developed, fostered by the way the scientific community operates. I am not either suggesting any faking of results.
          The history of Einstein's theories is not something I have studied in detail so I am no authority. I was certainly however under the impression that the Special theory was well established by the 1930s when the development of atomic weapons began. And the General theory from 1916 was established by the 1940s even though experiments continue in the modern era. Pointing to the reported deflection of starlight by the Sun as supporting General relativity has problems. There are optical effects close to the Sun which could account for it so it is no proof that light is deflected by gravity. And the explanation for the anomalous precession of Mercury requires the acceptance of other assumptions such as the concept of space-time which is nonsensical. Space and time are two different things which cannot be combined as a compound entity, in the same way that bananas and time could not. It is meaningless whether or not it is accepted by consensus. Also gravitational lensing is an assumption with no proof of the concept. And although gravitational waves have been searched for for a long time and in different ways they have never been detected. They are an assumed concept.
          Another problem these days is that in many experiments validation is given to minute data readings which are well within error and noise levels. And finally the assertion that gravity is the only significant force in cosmology is an assumption too. The interesting thing is that all of the main tenets of modern cosmology and astrophysics that I mentioned before are unmeasurable unattainable and undetectable concepts dependent on further assumptions.

          All of the assertions of the electric universe theorists are however observable, measurable, scalable and directly testable and backed up by continuing laboratory research.

          There are problems too with the stability of the solar system having been maintained for billions of years by gravity alone. There is no self restoring mechanism for planetary orbits subjected to any perturbation so the stability would be lost in a relatively sort period. That is how space craft are able to be steered and powered within the solar system. Something else restores and maintains the stability of planet orbits.
          I don't want to go on much longer here Andre but on the Whipple theory it does not matter what it is called. The problem is the ice. It has never been demonstrated to exist in comets yet is embraced as a certainty by many.
          The reasons that no ice would challenge conventional accepted cosmology are I. no Oort cloud 2. no sublimated jets. 3. no reason to suspect comets are primordial any more than asteroids are.
          If other measurements also point to electrical discharge phenomena occurring this negates the gravity only model of the solar system and beyond. There is much more to say about this but that will wait for future discussions.
          I realise of course that what I am saying is contentious but it should be discussed openly as we are doing here.

          Like you I hope the landing will succeed. It would have had a better chance if they had not made the ice assumption and relied on ice screws and harpoons to anchor it to the surface. There is a chance that the harpoons could ping off the rock and stick into the lander and even a chance that the ice screws could launch the lander away from the surface and off into space. I hope that neither of these happen and somehow they achieve a functional anchorage.

        • THOMAS says:

          @ AndreH "...I see a big chunk with features looking like rocks, other features looking like an agglomeration of boulders (with no evdence what those are made of)..."

          It's partly a question of probability. If so many features "look like" rocks, I simply assume they probably ARE rocks. Being able to make this sort of obvious assumption from detailed photographic evidence is probably also one of the reasons we’ve spent 20 years and over a billion dollars to get these pictures.

          It’s also a question of survival. That’s the way I function in the real world and presumably you too; and it’s thanks to that sort of realistic assumption that we’re both still both alive to have this discussion at the end of the day we’ve both spent: what today looked like several 40 ton trucks I decided not to drive head-on into probably were 40 ton trucks and that’s why I’m still alive.

          Above all, if those “agglomerations of boulders” happen to be lying mainly at the base of hundreds-of-feet-high-rocky-cliffs, as in every picture coming back to us, the “evidence” of what they “are made of” also seems pretty damning (for standard theory): what should stop us from believing that those boulders are made of the same stratified rock as the cliff faces they have presumably fallen down from, as in the real world? Particularly since we have photographic proof of their stratified nature: http://blogs.esa.int/rosetta/2014/10/29/cometwatch-26-october/ (Zoom in on any of the larger boulders to see the strata).

          What other sort of “evidence” do you require?

      • THOMAS says:

        @John "...or the idea that the shift of spectral lines towards the red end is related to speed of recession and therefore distance."

        The parallel between the history of red-shift and that of EU theory is already striking and may be made even more ominously striking by what will eventually be done to, and done with, the images and data flooding back from Rosetta as regards their implications for supporting or falsifying the competing theories.

        As you probably know, John, (though no mainstreamer seems to be aware of the fact any longer) Edwin Hubble was himself sceptical of the claim that the red-shift he had been the first to observe was proof of the speed of recession by a simple Doppler-Fizeau effect. It was lesser men who seized on his observation to turn it into the central pillar of the since heavily and desperately patched Big Bang theory as we now know it.

        As you probably also know, the “red-shift= recessional velocity hence distance” hypothesis has since been repeatedly falsified by the images acquired by Halton “Chip” Arp who, until his death a little under a year ago now, was undoubtedly the greatest observational astronomer of modern times. We owe him the extraordinary 1966 “Atlas of Peculiar Galaxies” which ensured that several hundred highly intriguing (and inexplicable by standard theory) celestial objects are still designated by their ARP number. They continue to challenge standard theory to this day.

        Arp’s observations show that several heavily red-shifted (and thus supposedly distant) objects such as quasars are clearly interacting with other only slightly red-shifted (and hence supposedly nearby) objects.

        Having thus falsified the standard theory, Arp went on to propose an alternative one, based on the notion of “intrinsic” red-shift, whereby the observed quantum-leaped shades of red-shift are a simple property of matter, related to its age after being ejected from a parent body (from an active/radio galaxy in the case of quasars). For daring to publish observations and to suggest a resulting model which in one stroke destroyed the most basic foundation of standard theory (red-shift=speed of recession), he immediately lost all his funding and all his telescope-time… RIP, Halton Arp, you did your best! But what a cautionary tale for equally curious, brilliant young scientists…!

        Arp’s observation-based ejection model ties in with the EU model which describes and predicts the fission of bipolar entities into dual or multiple objects through sudden violent discharge of the electrical stress created by the build-up of charge imbalance with the wider electric environment. The universal hourglass shape which I’ve recently referred to on a parallel thread (http://blogs.esa.int/rosetta/2014/10/29/cometwatch-26-october/#comment-140349) is part of the pattern.

        • John says:

          Well done THOMAS. It all needs to be out there and freely discussed allowing the self evidence to become apparent.

          • THOMAS says:

            John, you're right and it's great to see someone who remains optimistic about new, incontrovertible evidence being able to overturn a decades-old, ingrained, but falsified theory.

            Personally, I can't seem to get rid of the pessimism which Halton Arp himself expressed (understandably, given the shameful treatment he received from the scientific Establishment for daring to challenge its most basic articles of faith with actual observational evidence) when he wrote that ''Sometimes I think that Astronomy is not so much a science as a series of scandals.''

            Deep down, I still also dare to believe that the "truth will out" and that this mission will indeed be a Rosetta Stone for deciphering what the comets have to tell us, though not at all in the way that was initially expected by standard theory....

  • dave says:

    Mattias,

    great pictutes, it feels like i am there.

  • John says:

    Robin, A perfect, defect free crystalline structure in a solid material is the strongest state that can be achieved. In practice the presence of sub-microscopic imperfections reduces this theoretical strength to the sort of levels we are familiar with. The reason that fibre reinforced composite structures are strong is because of the relatively defect free structure of the small cross section fibres, not attainable in extensive materials. The presence of dust particles in an ice matrix would only impair the strength and the already poor fracture toughness. Fibrous inclusions could however conceivably increase strength but not fracture toughness. This is also likely to be the case in an amorphous structure.

    • logan says:

      Hi John.

      "...and resists fracturing vastly more than normal ice". Think it's a small finger 'typo'. Maybe should say 'tensing'.

    • logan says:

      It's a very interesting issue here, John. Crystalline structures here should be really 'alien' to the ones we are used to 🙂

  • Peter says:

    Thanks for the explanation. I didnt conclude this from "NxN pixel frame" being 665m. But, with my ruler, I could detect that the smallest black "rocks" on the picture might be some meters in diameter. And I think to be friendly to your users and friends of the project (and not "bluntly Russian"), a scale bar in the black of the space would not hurt at all and appreciated by many kids in our schools, too - and therefore no reason to send BIG thanks.

  • Clive Hartland says:

    So, thinking about it all we should go back to basics, my first thought is that the Comet 67P is a very big chunk of coke whizzing through space and getting attracted to various Suns and occasionally getting heated up by proximity to said Suns.
    Upon leaving it starts to cool down but reserved heat in this large chunk of coke still gives off various gases and chemicals just like heated up coke would do!
    The density of Comet 67P is like coke, porous and has its own gravity which pulls back any ejected matter as it travels.
    Ergo we have an answer to the dust and erosion and identification of its output.
    We do not know its history as it has been in existence for Billions of years and again who knows where it will go from here?
    We should revel in the fact that all the conjecture about Comets is de-bunked and a new science is created and maybe enough to sponsor another try at meeting another Comet in the future.
    I doubt we have the words and knowledge to say how this Comet works, maybe after the landing we will learn a little bit more but a lot is still conjecture or best knowledge.

    Clive

  • Robin Sherman says:

    John. I have no wish to lecture, but I have to point out the errors in your assertions. Fractures propagate along the crystal facets of a crystalline solid. The purer the crystal, the longer those crystal facets are, the longer and more destructive the fracture becomes. A crystal of pure anything will fracture more destructively than an impure crystal where the defects in the crystal interrupt the propagation of the crack and secondary cracks. If this were not the case, Diamond the hardest material known, would not be able to be fashioned into the beautiful, multifaceted gems we see. The purer the diamond the more complex and intricate the Jeweller can be in his design. The more defects and faults in the diamond the more restricted the number and sizes of facets that can be cut.

    Composite materials are stronger because they interrupt and shorten the length of these natural weak points in the crystal structure and provide cross ties to hold the smaller fractures in place. Steel is stronger than pure Iron, bronze stronger than Copper or Tin, alloys are invariably stronger than the pure materials on their own, particularly in relation to breaking strength.

    A block of solid ice dropped from a few metres onto concrete will fracture and shatter into thousands of pieces. The same sized block of Pykrete will maybe break in half. There are plenty of videos on You Tube where this property is demonstrated including one from Mythbusters and a number from children showing it is an easy and repeatable experiment. Also shown is the slowing down of the rate of melting. Further experiments by the demonstrators showed replacing the sawdust with shredded paper produced a material that was only able to be broken with multiple blows of a Pick Axe and in fact was less brittle than concrete. This is evidence you can see with your own eyes, by normal people who have no access to camera trickery or interest in fooling the public.

    Glass is an amorphous material, but it is not a frozen solid, at room temperature it is liquid, where gravity has time to align all the tiny crystals as they move very slowly in the liquid. As we know Glass, although very hard, is also very brittle and prone to destructive failure from the tiniest crack. Add a contaminant, such as a small metal atom, the Silicon Dioxide will form different shaped crystals around each atom, breaking up the linear rows of crystal faces. This type of glass is far less prone to fracture, thermal stress and breakage, the most well known of which is Pyrex glass.

    The ices on 67P are most likely amorphous in nature too, the cold vacuum of space freezing them very rapidly from any fluid state. Thus the contamination of these ices with tiny mineral particles and organic molecules will have the same effect as adding the small metal atoms to glass, or small amounts of metals, such as Vanadium, and Carbon to Iron, to make very strong steel. It will become more resistant to thermal and structural weakness. The level and nature of the ice contamination will determine its appearance, hardness, resistance to melting/sublimation and brittleness. It will still fracture along sharp edges, but will not shatter into tiny fragments. Instead bigger, far fewer in number, blocks are produced, as secondary cracks are prevented from forming and spreading out from the original fracture.

  • John says:

    I have to disagree with you Robin. There is no such thing as a facet within a solid crystalline structure. There are different planes of packing density of atoms depending on the unit cell type and some planes are weaker than others. These would be preferred fracture planes. The fracture strength of any solid material is determined ideally by the strength of the bond between atoms. In practice it is determined by the presence of defects in the structure which act as stress concentration points which promote fracture at a lower bulk stress. This would apply to all crystalline structures, brittle structures like ice included. It would also apply to amorphous ice and glass, also brittle, but in them it is conceivable that the interatomic bond strength could be improved by solution type additions without impairing fracture properties. In brittle materials the fracture strength is close to the ultimate strength. In general ice is comparatively weakly bonded and the addition of any stronger fibrous material to it would improve its tensile strength but not its fracture strength as the fibres would act as stress concentrations and promote the collapse of the ice matrix whether into big lumps or small.
    Metals are also crystalline structures but essentially ductile and therefore capable of plastic deformation, which is the stepwise movement of atoms past each other without separating, known as dislocation movement. Metal alloys can be solution strengthened or strengthened by precipitation compounds or other secondary compounds and in most cases both the ductility and the fracture strength will be impaired. The presence of solvent atoms or compound particles increases the force required to move dislocations and increases the strength. If this force however locally exceeds the force required to separate the atoms fracture is initiated.
    The addition of alloy elements to iron to form steels is a very complex topic with a vast range of properties available. Essentially though the same factors apply. Carbon added to iron forms ferrite, a solid solution with a body centered cubic crystal structure. Carbon also forms a non alloyed compound with iron called cementite. Both of these occur in steel structures, the quantity and distribution depending on a whole range of variables. Precise composition and cooling rate during solidification are a major ones. In the presence of other alloy elements carbon can dissolve to a greater degree forming a different solid solution called austenite which has a face centered cubic crystal structure and different properties. Other solutions are also possible.
    Much more could be said about metals and alloys but is outside the scope of this blog and a discussion of the likely composition of the comet, unless of course it turns out to contain significant amounts of metals, which is not impossible.

    • Robin Sherman says:

      Thanks John. "Fracture Planes" was what I was trying to, and singularly failing to explain it seems, but for the life of me I could not remember the proper term. My main point was that adding material to a crystalline solid does not always lead to a weaker material, as was the impression I got from your original post, and the extent and severity of fracturing can be mitigated by contaminants within a crystalline material. It is clear that was not what you intended, from the clarification in your second post.

      I hope I made it clear in my post that the way such a "composite material" fractures, would depend upon the exact composition of the material. Its hardness and tensile strength are another story. The other point I missed, but am well aware of, is that defects and inclusions as well as preventing the propagation of fractures are invariably the starting point of fractures. I will have to write these posts at an earlier hour and after fewer beverages.

  • dave says:

    Denis,
    Re Solar wind coments.

    It might be worth while to go on you tube, enter thunderbolts project, look for the electric comet.

    I was enthralled by the Cosmos since I was a kid of 8 in the 60's and was an avid reader, I counted down the years to see Hubble do a return but the dissapointing show did not dull my interest. Once in secondary school the maths of everything and the size and distance of the universe seemed awesome. However I was never that convinced by the model of the eveloution of our solar system, but even so, I hung on to the idea that comets were from the beguinning of our solar system. Then black holes relativity and quantim mechanics became interesting.
    I did not come across the electric universe until I caught site of a blog somewhere. There was an abusive discussion going on because an EU proponent was arguing that the sun was not driven by Fusion.
    I thought it was preposterous after my life long attachment to the std model.
    So I checked it out, specifically about what powered stars, not because of my childhood fascination of comets. It took time to come round but I did find a lot of sense in it.

    Anyway, the electric Comet video is a bit long from my recolection, as it attempts to tie in evidence from ancient observation, but it should answer your questions.
    A lot of the electrical evidence relies on plasma physics and specifically Birkeland currents, but that may make you think about it for a while even if it does not shake you from the std model first time around.

    regards

  • I thought it was preposterous after my life long attachment to the std model.
    So I checked it out, specifically about what powered stars, not because of my childhood fascination of comets. It took time to come round but I did find a lot of sense in it.

    Anyway, the electric Comet video is a bit long from my recolection, as it attempts to tie in evidence from ancient observation, but it should answer your questions.
    A lot of the electrical evidence relies on plasma physics and specifically Birkeland currents, but that may make you think about it for a while even if it does not shake you from the std model first time around.

  • So, thinking about it all we should go back to basics, my first thought is that the Comet 67P is a very big chunk of coke whizzing through space and getting attracted to various Suns and occasionally getting heated up by proximity to said Suns.
    Upon leaving it starts to cool down but reserved heat in this large chunk of coke still gives off various gases and chemicals just like heated up coke would do!
    The density of Comet 67P is like coke, porous and has its own gravity which pulls back any ejected matter as it travels.
    Ergo we have an answer to the dust and erosion and identification of its output.
    We do not know its history as it has been in existence for Billions of years and again who knows where it will go from here?
    We should revel in the fact that all the conjecture about Comets is de-bunked and a new science is created and maybe enough to sponsor another try at meeting another Comet in the future.
    I doubt we have the words and knowledge to say how this Comet works, maybe after the landing we will learn a little bit more but a lot is still

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