CometWatch – focus on the ‘neck’

This four-image NAVCAM montage, comprising images taken on 2 October from a distance of 19 km from the centre of 67P/C-G, provides a stunning view onto the ‘neck’ region of the comet. The image scale is 1.45 metres/pixel, so each 1024 x 1024 pixel frame is about 1.5 km square.

Four image montage of NAVCAM images taken on 2 October. Credits: ESA/Rosetta/NAVCAM

Four image montage of NAVCAM images taken on 2 October. Credits: ESA/Rosetta/NAVCAM

As usual, the four individual images making up the montage are provided at the end of this post. It’s interesting to see how the perspective has shifted and some of the features have changed in appearance as a result of the comet rotation and spacecraft movement in the time between the first (bottom left) and last (bottom right) image being taken. For example, look at the change in the length of shadows of features close to the ‘join’ in the bottom two images. So, a word of caution: while it is possible to make a seamless mosaic using software like Microsoft ICE, a careful check against the originals will very likely show areas that are incorrect. Note also that the diffuse ‘blob’ mentioned in Monday’s post and probably due to internal scattering in the NAVCAM optics, is visible again in the top two images in today’s post. Since the blob appears to blend into the jets seen in the top right frame, take care when cranking up the contrast!

You might also like to compare these images with those of the same region seen from a distance of about 28.5 km on 24 September.

Focusing on the lower right frame of this montage, you may spot some interesting features, in addition to the numerous boulders. For example, in the lower centre portion of the image, there appear to be exposed surfaces devoid of the smoother material that dominates the neck region (the exposed surfaces appear as brighter features with these image contrast settings). Higher-resolution images will hopefully tell us how thick this dusty covering is in this location, at least, and thus perhaps provide information about the rates of erosion.

Snaking through the centre of the frame, close to the shadowed portion on the right, is another curious feature. In some places it looks like a series of small pits; in others, they appear to merge into longer trough-like features – you can just about make out some small pits in the 24 September image. It will be interesting to get a closer view of these features, to see how they fit into the overall picture of the evolution of the comet.

As the comprehensive survey of 67P/C-G continues, efforts will also be made to learn more about the origin of the boulders and, of course, their composition. Are they relics from the comet’s interior, exposed by an erosive process that has removed material from around them; are they products of erosion from nearby cliffs; or were they exhumed by jet activity?

ESA_Rosetta_NAVCAM_141002_AESA_Rosetta_NAVCAM_141002_BESA_Rosetta_NAVCAM_141002_CESA_Rosetta_NAVCAM_141002_D

 

 

 

 

Comments

103 Comments

  • Peter G says:

    By asking questions -in this blog entry - that the Osiris team probably can answer already you do not make it much easier for your audience. I fully understand that preparations for the Philea landing take precedence, but would it be possible to give an idea for when the Osiris team will hold a first press conference?

    • emily says:

      Hi Peter, the plan is to have Rosetta science briefings during the media events being planned around the landing event next month (and which will also be live-streamed).

      • Comeatstalker says:

        Hello emily.
        Concerning the resolution of the Navcam.
        So far it is still making a pixel 2by2 binning in each frame, not to mix up with the 2by2 frame stitching for the mosaic image.
        So the resolution is tan(5)*19000/512~3.25 meter per pixel. 5 is is the 5 degree field of view in the Navcam and once the pixel 2by2 binning began when the comet filled the single frame of the Navcam and the mosaic imaging started this has to my knowing not changed. Please check with your Navcam team and reply if the Pixel 2 by 2 binning in each of the four frames is or is not applied. Another reason to do the pixel binning is to improve its signal to noise ratio and its sensitivity. So the sum of this is that before the binning the navcam had 1024*1024 pixels for a 5 degree field of view and now we have the pixel binning and the mosaic stitching resulting in a 1024 by 1024 pixel 10 degree field of view.. Just trust me and if not the check with the Navcam team.

        • Mark McCaughrean says:

          There is no pixel binning used by NAVCAM. Each image that comes down has the native 1024 x 1024 pixel resolution of the NAVCAM sensor, and we make those available here as individual frames.

          Each pixel subtends 17.5 x 17.5 arcsec, meaning that the full field-of-view of a single NAVCAM image is around 18,000 arcsec or 5 degrees.

          When we got so close to 67P/C-G that the comet started over-filling the FOV of a single NAVCAM image, we started making 2 x 2 rasters, i.e. taking 4 individual images offset, to cover the whole comet.

          If you download the full-resolution version of the montages we are releasing now (click on the image and then download the full-res version using the link under the inline image, you'll see that they're just over 2000 x 2000 pixels: for example, the one in this post is 2072 x 2072 pixels, which is the 2048 x 2048 pixels of a 2 x 2 raster of individual 1024 x 1024 pixel images, plus some black space down the middle to keep the images separated, and a bit of a black frame.

          This then makes an image covering roughly 10 x 10 degrees, but at full 17.5 arcsec/pixel resolution.

          There is definitely no pixel binning going on.

          • Comeatstalker says:

            Thanks for the reply, somewhere in the time line i missed the notification that the pixel binning that once was noted to be, is no more, so now we can calculate with about 85 micro radian per pixel in the Navcam and 19 micro radian per pixel for the Osiris NAC, great.

  • DavidW says:

    Thank you Em,
    Great and getting greater.

    You know how we all keep going on a bit

  • John says:

    Strange how the words plasma and electrical discharge are absent from your vocabulary. Will this persist throughout the mission.

    • emily says:

      Not true – we have a suite of plasma instruments on board no less! http://sci.esa.int/rosetta/35061-instruments/?fbodylongid=1644

      • John says:

        I know that Emily so what is the source of the plasma to be measured if it is not the jets blasting from the surface into the coma and which are still being called sublimated gas from the interior.

        • Denis says:

          Huh ? Plasma is just ionised gas.
          The fact that there is plasma around the comet does not mean that surface changes are due to electric discharge effects.
          Gas can sublimate from the interior then get ionised by the solar wind, which is itslef a plasma and fils up the whole solar system.

          • logan says:

            You have a point here, Denis.

            We still have non-random 'surface changes'.

          • logan says:

            Of space I don't model on 'discharges'. Quite closed systems. Only flux and isolation.

          • John says:

            Not an ionized gas Deniis, an ionized or partially ionized state of matter with neither the properties nor behaviour of a gas, And indeed the proton stream from the Sun is an energetic conducting plasma that sputters the surface of the comet rock releasing a stream of negative ions as a plasma jet, where there are no holes or fissures in the rock. No gas required.

          • Denis says:

            John,

            I understand what you mean, however, my point is that the plasma can also be explained by gas being released by sublimation of any sort of ices present in the comet, releasing low-energy gas. Then the solar wind ionises this gas and the comet gets its "own" plasma (leading to the plasma tail).
            So I don't see why the presence of plasma by itself pushes for one theory or another.

            What is not clear to me is why, in the "electrical etching" explanation, there would be localised jets at certain points on the comet, as it would seem that this phenomena would be much more homogeneous and much progressive than any thermal effects from the solar radiation (by that I mean EM radiation).

        • Maksim says:

          The sublimated gasses get ionised by the solar wind, hence the plasma around the comet. That's what creates the ion tail.

          • john says:

            Quite right Denis. The presence of plasma is no proof one way or the other and there certainly will be neutral gases there too, which will at least partially ionize in the proton stream but neutral gases will also form in the coma. To determine the nature of the jets it would be necessary to take measurements as close to the comet surface as possible. The localization of the jets is much like lightning discharges. It is at points of charge concentration on the surface like cliff edges and pinnacles.

          • John says:

            Denis, my reply to you seems to have disappeared so i will try again. You are right that identifying plasma does not prove things one way or the other. Ionization will occur in the coma and also neutral gases will form there because of the abundance of hydrogen ions streaming from the Sun at 350 kilometres per second. The jets would therefore need to be analyzed close to the comet surface to determine what they consist of.
            They are localized because they initiate at points of charge concentration on the surface like cliffs and peaks, and in the smaller cross section of the neck region. Because of the topography of the surface of this comet the number and intensity of jets is likely to increase and they could also change position unpredictably.

    • logan says:

      Hi John, if you want to trash your mind even more download

      http://blogs.esa.int/rosetta/files/2014/10/ESA_Rosetta_NAVCAM_141002_A.jpg

      And look at those 'smooth' surfaces, doubling size and contrast.

      • John says:

        Trash logan? It is clear which minds are trashed. Those that believe the baseless fairy story about the dirty snowball and the evolving gas.

        • John says:

          By the way logan your isolationist concept is an obsolete tenet of faith. Nowadays it is established that planets are connected to at least some of their moons by plasma filaments, and also the Earth to the Sun. And the plasma is a stream of ionized (charged) particles ie. an electric current.

          • Steve Kasian says:

            @John: You've been listening to New Age "theorists" rather than real scientists. There is no real science in those ideas.

    • Comeatstalker says:

      Plasma and electrical discharge you have for example in a fluorescent tube that is turned on illuminating your desktop and consuming about 20 Watt power comming from a wall plugg or so.

      Around the comet the plasma is million-folds thinner then inside this lit up fluorescent tube. Its electrical energy it receives to become a plasma comes from the solar-wind and high energetic radiation.

      Instruments on Rosetta are measuring this. Some satelites around earth does this trick as well, on those earth orbiting instruments the polar lights are the concern and the density of this plasma is thousandfold denser than around the comet.

      Around the sun there is also a Plasma fairly dense an millions degree hot. More information about plasma is to be found on Wikipedia.

      Hoped this helped to enlighten a bit about plasma.

      • THOMAS says:

        "...this plasma is thousandfold denser than around the comet."

        Do you have insider information in the shape of Rosetta-acquired data to be able to assert this or is it just the standard mantra being relayed by the usual suspect, Wikipedia?

        • Comeatstalker says:

          http://www.iaea.org/inis/collection/NCLCollectionStore/_Public/17/063/17063910.pdf

          The comet Haley Plasma Is to be assumed a lot denser then 67PCG will ever reach. Other cometary tails are also scanned. Im not sure if Wicki is the perfect source of knowledge but for most of not academic people it does a lot, if more accurate info is required it is possible to get access to password protected material on the net and this has nothing to do with inside information.

          • THOMAS says:

            The paper you link to dates from 1986...

            "...assumed..."???

            Why? How?

          • Cometstalker says:

            Comparing the size and mass of the two comets and its orbits makes the assumption doubtless.

      • John says:

        Not new age theory Steve Kasian but the science of plasma physics. There is loads of evidence of plasma connections between solar system bodies. NASA have plenty of it. The isolationist story you believe in is pure invention.

  • Peter G says:

    Thanks, Emily. I hope you understand we all hold our breadth in expectation of.. the unexpected.

    • THOMAS says:

      "I hope you understand we all hold our breadth in expectation of.. the unexpected."

      But which some of us are actually expecting, not to say predicting.

  • john gury says:

    That quad montage looks so much like a bat in space.

  • Bill says:

    Here are the dust Jets in the current Navcam 2 October 14 image, enhanced to the max:

    http://univ.smugmug.com/Rosetta-Philae-Mission/Rosetta-Dust-Jets/i-jkmx6Wp/0/L/Comet_on_2_October_NavCam--enh--jets--mask-L.png

    --Bill

    • Comeatstalker says:

      The central part of each frame has a circular "cloud" that is Not due to dust but a self reflection in the camera and is called Narcissus effect by optics designers like me. It is present on all dark frames in the Navcam. You could make your own "dark frame" and substract this in your image processing, you only need a "slice" of the image from its center to the rim to creat a dark frame for this purpose.

      • logan says:

        Thanks a lot, Comeatstalker. Somehow knew it has to be with the very high contrasting.

    • Kamal Lodaya says:

      Since the jets appear to be quite broad, does Rosetta manage to avoid them all the time in its orbit? If not, can it "feel" the difference when passing in front of them?

  • Robin Sherman says:

    Emily, it seems you have got caught up in the speculation game like the rest of us. The only difference is that you might be a little better informed of the science team's current notions than us. For that we are grateful and encourage you to continue in that vein. Many thanks.

  • Stephan Andersohn says:

    Do you know why the neck is active already? From my point of view it shouldn't because of the less radiation from sun in shadow

    • Steve Kasian says:

      It makes sense that the "neck" is the most active region if you consider the very likely possibility that the comet's topography has been morphed into it's present form as a direct result of erosion caused by the uneven sublimation of the various ices of which it is comprised. The material that makes up the "neck" area is likely more volatile than the rest of the comet body. The "neck" was likely "filled in" with more material previous to sublimation processes which excavated the area, which likely formed the deep trough, or "neck", that we see today.

      Of course, this is only one of various hypotheses related to the comet's composition, geomorphology, and history, but the heavier outgassing at the "neck" would seem to lend credence to the idea.

      • logan says:

        Haven't hear that, Steve. If so then contact binary is not so far away...

        🙂

      • Stephan Andersohn says:

        It's clear that depenting of the inner structure the neck was created by more errosion but why it's still the same? Based on the geometry there should be some times of shadow that cools down the surface. To get more vapore from the neck it should be darker to reflect less energy than the surfaces around. But if you see the Pictures it not like that.. May there material with less density so same light sublimates more volume of material.

    • Kamal Lodaya says:

      Stephan: Great question, can we turn it around and ask, is it possible that even at aphelion some parts of a comet continue to be active?

    • Comeatstalker says:

      Time to realize that the activity is not due to solar radiation yet but driven by gravity and tidal effect as the force in the neck region is over 300 mega Newton between the two bodies of the comet and the comet has a material that is NOT hard rock but rather a charred, soaked, frozen toast. This has been going on for a while even before Rosette was not there yet. These activities are are at maximum when the comet is closest to jupiter respective to sun and they come from the inside of the comet. Later when the comet receives an about 1.1 kilowatt per square meter solar radiation level the surface will get active, so far it recieves about 140 Watt per square meter and the surface is well insulating.

      • Marco says:

        @comeatstalker One question comes to mind, though I do agree that there is great pressure inside the neck, is "why aren't the volatiles within the neck liquefying due to the pressure and temperature?" This would causie extra forces on the remaining volatiles, liquefying them in turn until the neck collapses and the lobes join. The structural integrity of the neck defies the hypothesis that there are more volatiles in the neck.

        • Comeatstalker says:

          To calculate the force between two masses is easy, then to do some other calculation to get the ciricumface it will show that the areal pressure is as low as a few milli Bar. This in combination with a low internal temperature results in the conclusion that the structure remains solid and not liquid

          UNTIL due to structural collapse in any scale releases energy that creates heat and pressure enough to partly liquify mixtures of ice. Some of the liquids will enter the surface and evaporate due to the rapidly lower close to vacuum pressure. Then we call it jets.

          A lot of other tricks and ideas are possibly but the simplest way is the easiest to understand, ideas like nuclear tick tack inside comets and micro dark matter black holes i can not understand well enough to give belief.

          • Marco says:

            Comeatstalker - it does not need any fantastical ideas for it not to be simple. A low density "rubble pile" does not have the integrity to hold that kind of pressure. If you say the pressure is distributed evenly across the neck, what sort of solid, low density volatile mixture would hold that structure, still sublimate, but not collapse?

          • Comeatstalker says:

            Rock-Wool or worst quality styro-foam can easily handle multiples of this pressure-levels and has a density a few times less than the comet. It is stable by evidence but if the stability is disturbed then great amounts of energy is released if a huge lump like the head of the comet looses its foothold and stumbles a short step into the the neck region. The kg m/s is the same on the comet as on earth and enough to alter the temperature of the inside parts of concern from cryogenic to steamy hot. When Philea has landed comet quakes will tell us more.

      • Steve Kasian says:

        @Comeatstalker: With all due respect... fact is, the numbers you're claiming to know are impossible for you to know, even as approximations. You have no data on what the density and mass of the comet are, a gravity map of the body, nor any data on it's composition. For all you know, a single grown man could possibly have the strength to hold the two "halves" of the comet apart with only his body without being crushed. This is specifically why Rosetta is there - to take measurements and provide this data, so that scientists can fill in the blanks which you claim to have already filled in. 😉 It is fun to speculate, though.

        • Cometstalker says:

          The comets mass and volume are measured to a satisfying accuracy. The only lack is the distribution of its mass, there could in theory be a pair of iron-nickel cores inside the comet and this would make it even more spectacular.

  • Thomas says:

    Here is my version of this mosaic:
    https://www.flickr.com/photos/105035663@N07/15294330878/
    Thanks for your great blog Emily!

  • Ross says:

    That long "series of pits" can be compared directly to "crater chains" and "sinuous rilles" observed on many different planetary bodies. The mechanism that caused this feature is a discharge moving across the terrain. Upon closer inspection I'd suspect that many of the pits would overlap others while leaving no material near the edges, as if they've been scooped out.

  • Robin Sherman says:

    Some points of extra interest I have picked out after a quick close inspection of this image.

    1. The bottom left quadrant. On the right edge, about a third of the way up, is a bright ledge. Towards the back right of this ledge, on the very edge of the picture is a small black circle. Behind it there is a small scarp. Moving from left to right along this scarp, about half way along it goes from clearly defined to fuzzy and further along clear again. This fuzziness runs down to the black circle. Fortunately this feature also appears at a slightly different angle in the adjacent quadrant. Here the fuzziness is a little broader, but the black circle can no longer be seen. This I think rules out a camera or processing artefact. This looks to me like a small fan shaped plume of dust/gas.

    2. In the top left quadrant. Move straight up from the big, bulbous mound at the top and centre of the comet's big lobe. A small object, maybe 10m across with a jet about twice as long emerging below it. Does 67P have a satellite? I think we would have heard if it did, but past experience suggests maybe not. More likely a camera artefact or a very close bit of dust.

    3. The bottom right quadrant, as Emily says, is full of interest. Follow the line of the cliff shadow edge down until it meets a bright ledge/cliff. The back of this cliff is in semi shadow or shadow, yet two very bright "rivers" of material can clearly be seen. It looks like fresh ejecta to me. Back on the ledge/cliff face there is another area of fuzziness which could be another emission phenomena, though it is not as clear as in point 1. Moving upwards into the cliff shadow, the point where the cliff meets the valley floor is just visible. Here there is a horizontal row of little "sprites", or what look like little jets of brighter material. On the edge of the shadow, just to the left of these, is a darker circle with what appears to be a plume of dark smoke coming out of it. Being on the edge of the shadow this maybe wishful thinking, but to its right the first of the "sprites" also emanates from a dark circle.

    I am sure others will find other nuggets of interest on zooming in on this image. At least this image is at a resolution where such things are more than just a few indistinct pixels. Still open to interpretation though and I fully understand if others view these features differently.

  • Robin Sherman says:

    Logan asked about crystallography. The bight exposed, smooth area Emily highlighted in quadrant 4, has rectangular and square areas on its surface, like tiles or the faces of crystals.

    When lava cools very quickly, it can form hexagonal columns as seen famously at the Giants Causeway in Ireland. The hexagonal shape is a direct reflection of the hexagonal crystal lattice the rock crystals set in. Water Ice has a cubic lattice. If liquid water freezes rapidly enough I imagine a similar effect would occur and square columns would form. Each column would be metres across. Perhaps this is the evidence for liquid water having been temporarily present on 67P. In addition it gives the appearance of flowing over the edge of a crater wall. How about them apples?

    • Comeatstalker says:

      Liquid water at any temperature of your choice freezes in vacuum rapidly, it freezes due to its boiling in the vacuum leaving a very strange grayish ice full of micro channels and as far from crystalline as ever possible, also very brittle. Get a vacuum flask and a vacuum pump ad some water and see what happens, i do this a lot to show friends how to get ice for the drink in a hurry.

      • Robin Sherman says:

        Oh well another Heath Robinson theory disproved. Thanks for the info though. It does "look" like the nearest thing to exposed ice, of whatever chemical composition, seen so far.

      • logan says:

        What if we extract 'quick' word from Robin's log?

      • Comeatstalker says:

        I did a mixture of 80% water, 5% amonia, 10% ethanol but no methanol as I do not like its poisonous properties the rest was aceton. It mixed quite well and cooling it to a slushy mixture was fun, then i put it inside my vacuum flask and turned the pump on. It boiled like cracy and turned very quickly into an extreme fluffy sort of ice not at all like the ice made with this methods using pure water.
        This has nothing to do with what is happening on the comet but my point is that as long as we do not know the exact properties of substances that this comet contains in its inside guessing is all that remains and until Philae has made its job we know just about nothing about comets.
        General comet tails we know quite well not only from wikipedia but never before we had the opportunity to get really close to its origin, and this time even knowing its coming from inside of this comet and not yet from its heated surface. Also we know by now that this comet has quite a low average density, should there be dense cores then its even more spectacular and this might be indiceted by the Concert experiment.

        • Robin Sherman says:

          Hi Comeatstalker. A practical experiment, brilliant! When you say "fluffy ice", can we take that as meaning a low density, porous ice? I agree we need information on the ratios of ingredients to draw definite conclusions, but given I am still finding it hard to get my head round this 0.4g/cm^3 density, what you found makes things a lot easier to conceptualise.

          As is my way, I shall think out loud and see where I get. When tidal stress and pressures generate heat and cracks, perhaps temporarily liquids are present, that then boil generating large vapour pressures as well as freeze to this expanded, fluffy ice. This could then, with the aid of simultaneously released gases, such as Nitrogen and Argon, propagate these cracks to the surface. Ices at these low temperatures are extremely brittle, being porous as well, only making them more so. At the surface, pressure is released, rapid sublimation occurs, dust, ice and gas are expelled.

          The vent point would soon block up again with the fluffy ice, restoring structural integrity, be covered with heavier ejecta and essentially just leave shallow furrows and dimples on the surface just as we see in the neck region. Cryovulcanism essentially, as seen on Triton, Titan, Enceladus, and Europa, but here on a lot smaller scale. The streamers look spectacular, but as others have explained, they are in actuality diffuse and slow, we should therefore, not be looking for gaping holes in the surface as their source.

          No evidence of jets from anywhere on the lobes so far, just a barely visible haze of minimal sublimated material. There is very little energy reaching the ices below. The neck however is losing material at a far greater rate already and has been for many months, perhaps continuously. When the comet gets closer to the sun and the postulated subsurface sublimation starts to increase, this will occur all over the comet. The neck region will be losing more material still, a "double whammy" of material loss. The neck region is thus more eroded and appears to have more ejecta on its surface.

          Thanks Comeatstalker, my "world/comet view" is now starting to crystallise and make sense., in this area at least.

          • Comeatstalker says:

            The ice with pure water boiling in vacuum is a lot lighter then Crystal clear ice and it depends a lot of how well the pump is performing. If the pump runs at its maximum this ice is about 40% grey in color and has a density of 0.7kg/l
            If a mixture of water and some additives tha boil easier are made plus the mix is cooled to about -15C it boils wildly when the vacuum is applied and sputters around to sort of foamy fluffy structures that are snow white. Measuring its density is senseless in this state but my estimate is that parts of it is under 0.1kg/l

          • John says:

            To Robin Sherman

            Hello Robin, You talk about ices and sublimated gases as though these phenomena have been demonstrated. They never have, particularly the presence of ice on or in a comet. It is an imaginary concept from Fred Whipple that has been embraced by the scientific community. The results of all comet encounters in the last 20 or so years show that they are solid rock bodies containing minerals formed at high temperatures, like the inner planets of the solar system.. Have a look at the results of the Stardust mission to comet Wild 2 and the mission that fired a copper impactor at the surface of comet Tempel 1. No ice was identified in either case. As for the density quoted of 0.4 g/cc this seems unrealistically low unless there are some large internal cavities. There are basalts with densities of just less than 1g/cc and ice would be close to 1 unless it were absolute fluff with no mechanical strength whatsoever. It would be interesting if someone at ESA could publish the calculation that arrived at the 0.4g/cc .figure ( ie how the mass was derived).

  • Stu says:

    My "Cumbrian Sky" blog's latest 'tour' of Comet 67P... http://cumbriansky.wordpress.com/2014/10/09/a-canyon-on-a-comet/

  • Bill says:

    Great Blog text this morning. Thanks!

    Here is a comparison of the jet vent activity on the North Polar Plain between 24 September 14 to 2 October 14. Although I have tried to match the scale and orientation, there is enough difference in the camera location to cause a perspective shift.

    The scale on the 2 October image is 0.75 m/pixel.

    http://univ.smugmug.com/Rosetta-Philae-Mission/Rosetta-Comparative-Series/i-H4KxsRT/0/L/24sept_2oct-14_vent_activity-L.png

    --Bill

    • Kamal Lodaya says:

      Bill: You have been doing some amazing work, many thanks. About the whiter parts that we see in different pictures of the neck, I am not sure they can just be explained away using sunlight angles. Is the explanation whatever process of emission from the subterranean one is rooting for, or is this dust deposits being blown from the jets or from elsewhere (what is the source then)? Earlier there was mention of weaker jets from the larger lobe, can we find similar evidence when we look at the pictures there?

      • THOMAS says:

        I agree, those "whiter parts" cannot "just be explained away using sunlight angles".

        The whiter parts (apparently the summits of protruding rock) are actually orders of magnitude whiter than the other, merely "off-white" areas of this crucial neck region, where all those dead-straight "jets" are shooting up from.

        The blaze of energy emanating from the neck region has apparently made people forget that the whole comet (including even the seemingly snow-white neck area) is in reality as black as charcoal. The images have simply been processed to highlight contrast. (And thanks to everyone involved, because otherwise we would not have seen anything, except perhaps those "whiter parts"...).

        IMHO, the "white" of those protruding rocks at the lower left of the neck region is the result of high energy electrical activity, producing white-hot temperatures capable of melting the rock, as in the arc-welding processes which have been used down here on Earth for many decades. The molten silicates thus produced will flow down to further extend that apparently “white” blanket (but in reality totally blackened by the burning process) which already covers most of the neck region.

        The upcoming OSIRIS images (along with other data being recorded by the on-board RPC battery of instruments) should be able to confirm this. I can wait.

      • Bill says:

        We are at the point where many of the answers raise more questions. Happily, we will have a long time to survey this world.

        Even the "white areas" are pitch-black, like a lump of charcoal. They are just less pitch-black than the adjacent areas. The images we are getting have already been stretched and any subsequent processing increases the contrast. It is a tribute to the camera design and designers that it works so well. Bravo.

        The jet processes are more subtle at this point than we suspected. Later on, when the comet is nearer the Sun and is really cooking, I'll speculate that it'll look like a cauldron. Maybe... 😉

        --Bill

  • Helmut says:

    I don`t understand, why the object, Rosetta is scheduled to land on is now called a " Comet". I thought, its an asteroid in the asteroid belt between Mars and Jupiter and believed that comets ( by definition) consist out of ice and dust only...

    • Steve Kasian says:

      It's not an asteroid; It's a comet, and has always been a comet. It does not orbit the sun in the asteroid belt between Mars & Jupiter. You're apparently confusing objects. I would direct you to the "Where's Rosetta" link so that you could see the comet's orbit in relation to the solar system, but ESA seems about as interested in maintaining their website as they are in informing the public on the latest science from the mission. :-p

      https://util1.estec.esa.int/rosetta/where_is_rosetta/

      PLEASE FIX YOUR WEBSITE, ESA. THE ABOVE LINK IS DEAD AS OF THE DATE OF THIS POST.

      • emily says:

        It is not broken, but you should get a redirect to: http://sci.esa.int/where_is_rosetta/ . Just follow the link from the right hand panel of this blog and you get there just fine...

        • Comeatstalker says:

          Does not work on Ipad ios 8 please tell your webdesigner, i have notifyed Apple.

          • daposter says:

            works on linux though, which is really nice, which means it should work on BSDI (aka IOS) too... it is just flash.

            very nicely done by the way (I let it run sometimes just for the random background music 🙂 )

        • Steve Kasian says:

          @Emily: Noo redirect. It gives a 404 error (Please fix!):

          Not Found

          The requested URL /rosetta/where_is_rosetta/ was not found on this server.

          Apache/2.2.15 (Oracle) Server at util1.estec.esa.int Port 80

      • THOMAS says:

        Steve K.,
        The distinction between “comets” and “asteroids” has been totally blurred (and possibly obliterated) by recent observations.

        Perhaps you should read up on the Centaurs (half comet –half asteroid bodies on eccentric orbits)…. For a mainstream view, I suggest this recent NASA press release: http://www.jpl.nasa.gov/news/news.php?release=2013-234 (note the bewilderment…) and for a more hard-hitting dissident interpretation: http://www.thunderbolts.info/tpod/2011/arch11/110518asteroids.htm

        So when an asteroid suddenly becomes a comet, has its rocky substance been magically transformed into dusty ice (or icy dust)? And why DOES Comet 67P/C-G look so absolutely ROCKY?

  • Dave says:

    Re Vent activity,
    A lot of the proposed vents apear to be grouped in straight lines, also there are often roundish boulders at the end of the lines.
    Is it possible that some ot these so called vents are merely the track of a boulder that has rolled down a slope (very difficult to see which way the weak gravity is acting I admit) That would mean that the percieved vents would be just a witness where a rock had left the ground and and touched down heavily, leaving a track spaced with small depressions?

  • Comeatstalker says:

    Getting four pictures in time laps and at different orbit positions and angles also has the option to improve the accuracy of the navigation, i suppose the Navcam team is avare of this and if not please give them a nod. The Navcam is an instrument for the navigation and optionally we get some fancy images as a surrogate for the audiences urge to get some Osiris images.

  • Comeatstalker says:

    We have seen a lot of pictures with "streamers" so far but not a single note of how fast these jets are leaving the comet. Are these streamers actually leaving or entering the comet? The vector length and direction of these shapes are of major interest and not its presence.
    Can anyone at ESA spoil us with some information in a way that does not step on some scientists toes?

  • Here's our contribution to this last mosaic:
    http://www.aliveuniverseimages.com/speciale-missioni/missioni-nel-sistema-solare/rosetta/979-rosetta-abbassa-ancora-l-orbita-a-soli-10-km-dalla-superficie-di-67p

    ...to be honest there're 3 #CometWatch at the same link: 24 and 30 September, 2 October.

    For this last processing we decided not to turn up the brightness to see more of jets, although many versions can be realized and even overlapping.

  • Dave says:

    Hi Emily,
    do we have any theories or evidence of what the white river like shapes on the surface are.
    Possibly if it was ejecta, then maybe it is the material of the jets re freezing after it ejected, based on the std model of ice sublimating from below the surface.
    Equaly if the white ribbons are hot areas then maybe its evidence of electrical activity.
    You have instuments to detect ice on the surface and also to detect electrical activity.
    There must be a bit more you can say these features

  • Took a little time this time but here it is:

    http://mattias.malmer.nu/2014/10/comet-on-2-october-navcam-the-rift/

    3DTV and Anaglyph movie versions.

    /Mattias

    • Robin Sherman says:

      Great stuff again Mattias. Looking at the anaglyph there appear to be many linear and circular outlines on the image that appear to be furrows in the surface layer. I can't see evidence of these on the 2D pictures, so is this an effect of your anaglyph making process? If not perhaps evidence of subsurface cracks or sharp, but small, elevation angle changes.

  • Leo Vuyk says:

    Carbon surface layer cracks?
    Increased Light reflection areas at comet 67P CG, due to Carbon dust surface layer cracks originated by funnel pressure tectonics?
    According to Quantum FFF Theory, Comet 67P C-G has an internal Hyperion/ Coral funnel structure (volcano alike, see below) in combination with Central dust production (H2, O, C and even N) As a consequence, 67P shows a rough surface (with craters, trenches and peaks) continuously deformed and created by the dust production from the inside point sources.

    https://www.flickr.com/photos/93308747@N05/15300085537/in/photostream

    • THOMAS says:

      Leo Vuyk, thanks for the link.

      I looked out the rest of your photostream and was actually more interested in image 194, where you make a comparison between the shape of Comet 67P/C-G and that of the so-called “dying” or “doomed” star Eta Carina: http://hubblesite.org/gallery/album/star/pr1996023a/large_web/

      I was intending to point out the similarities myself in a future post: two distinct lobes separated by a “neck” (or rather “waist” in the case of Eta Carina), with spectacular “ejecta” or jets emanating from the “neck/waist” region. Intriguingly, as you also point out, the comparison even seems to extend to what you call “trenches and crater holes” visible on the surface of the nearer lobe (a “surface” made up 100% of plasma, of course, like the surface of our Sun). The scale is obviously not at all the same (nor the state of the material, for that matter) but we see the same sort of phenomena.
      .
      I have a different interpretation: I see electromagnetic forces at work, shaping these two totally disparate bodies into an hour-glass form, with extreme energy concentrated in, or emanating perpendicularly from (and probably both), the neck/waist region, which seems to be typical of so many cosmic objects we have acquired images of thanks to Hubble:

      http://hubblesite.org/gallery/album/entire/pr1997038a/web_print/
      http://hubblesite.org/gallery/album/heritage/pr2005025a/large_web/
      http://hubblesite.org/gallery/album/heritage/pr2005025b/large_web/
      http://hubblesite.org/gallery/album/entire/pr1997011b/large_web/
      http://hubblesite.org/gallery/album/entire/pr2006014f/web_print/
      http://hubblesite.org/gallery/album/entire/pr2004046a/large_web/
      http://hubblesite.org/gallery/album/entire/pr1999032c/web/
      et alia…

      IMHO, it’s all a question of pattern recognition, which we all use in our everyday lives without knowing it (otherwise, to take just one trivial but, I think, graphic example, we’d already all be dead or in debt because of the number of road accidents we would cause/be victim of, each time we tried to turn a steering wheel …). “Pattern recognition” is still fortunately the norm in the applied sciences, otherwise we’d still be in the Stone Age.

      Perhaps the most astonishing examples of what I personally take to be an overall organizing principle shaping things into “hour-glass”-type objects are to be found at the scale of galaxies, starting with our own Milky Way:
      http://www.dailygalaxy.com/my_weblog/2013/03/in-2011-an-analysis-of-data-from-a-nasa-fermi-gamma-ray-space-telescope-turned-up-massive-previously-unseen-galactic-struct.html
      but also, further from home:
      - Centaurus A: http://www.dailygalaxy.com/my_weblog/2011/01/1043-on-your-milky-way-dial-radio-galaxy-centaurus-a-more-than-one-supermassive-black-hole.html
      or
      - Spiral 0313-192 : http://starburstfound.org/superwaveblog/?p=195
      among others.

      I suggest that the overall organizing principle, at every scale, is the infinitesimal difference between a plus and a minus. Apart from being the most fundamental concept in mathematics, we now know that this tiny but absolute opposition also drives the infinity complex mechanisms of every one of the billions of cells in our own bodies (and not just in the brain). At a much smaller scale, we have long known that it organizes the atom.

      From this practical starting point, I don’t see what should prevent us from believing that Nature (or whatever we call it) is basically lazy/economical/efficient and that the same fundamental +/- principle (which has, in our modern world, become indispensable to all of us in the shape of both electrically powered machines and installations, and data processing principles) also applies to the infinitely large, about which we are necessarily less sure since laboratory experimentation and subsequent practical applications are more difficult to organize.

      I eagerly await the scientific results from Comet 67P/C-G which could help to confirm this model.

      • Leo Vuyk says:

        Thomas,
        Thanks for your extensive explanation.
        In my proposal for Quantum FFF theory it is assumed that there are four kinds of dark matter black holes,
        1: The Big Bang – or Big Crunch Black Hole, the origin of the cyclic multiverse.
        2: Primordial Big Bang splitting Black Holes as the product of the exploding Big Bang black hole, identified as a pairing an splitting process of Galaxy Anchor Black Holes (
        GABHs,
        3: Supernova Black Holes identified as the origin of Stellar Anchor Black Holes (SABHs, ). formed after a dual splitting process as Herbig Haro hotspots.
        4: Electro Magnetic Interference Black Holes, described as the origin of so called Quantum Knots also called Glueballs ( SM) found in my simple lab., and the origin of Ball Lightning, Earth bound Micro Comets, Solar related Comets and Sunspots.

        see also: http://vixra.org/pdf/1410.0039v1.pdf

  • logan says:

    Two vectors movement:

    This extruding needle at pixel 596,63 of

    http://blogs.esa.int/rosetta/files/2014/10/ESA_Rosetta_NAVCAM_141002_A.jpg

    is 'pinching' the surface 'chocolate' material.

    Curvature tells of improvement both on the surface and the extruding.

    Beautiful dust 'drawings' around, if you play with contrast.

  • logan says:

    Pico bar presure, yes. But raining dirt and dust.

  • logan says:

    Dust drawings at pixel 609,41. Visible without contrasting.

    4 localized neck deposits in a pile. At the bottom of the 'big wall'. Showing their 'duct' origin. Pixel 408,495.

    http://blogs.esa.int/rosetta/files/2014/10/ESA_Rosetta_NAVCAM_141002_D.jpg

    • logan says:

      Well, this brings Alter 'tide' arguments back to the play.

      😉

      • logan says:

        That's a lot of 'ground' material!

        Maybe the neck material is cold, but the 'wall' should be warm.

  • logan says:

    Lots of structures are so 'origami'.

  • logan says:

    Thanks a lot NAVCAM team, for allowing to see what others deliberately hasn't. This is the most beautiful astronomical object I have seen ever. If visually complex in an infinitely fractal way, offers hope it is governed by simple laws...

  • daposter says:

    looking at this 'plume' before the black background (It's still a better vacuum in that plume than in most electron microscopes I guess):
    is there any dependency on that activity on the surface temp, or surface being lit by the sun or not?

    I would search in comments first, but there does not seem to be a 'search comments' link to search all comments for this blog.

    Why I ask: would be interesting to kow if that is more surface temp dependent, or more deeper underground dependent.

  • Joao Fonseca says:

    Hi, guys! Congratulations for this astounding scientific achievement! Tip: I would be very pleased if you could put a man on scale on the surface of the comet, just to have an idea of its relative size!... thanks!

  • Dave says:

    Water Water Everywhere
    But not a drop to drink.......

    There is still lots of conjecture about is there water on or in the Comet, and if not why is it in the coma?
    So ithought I would share this;
    Here is an interesting NASA article in which it is conceded that the presence of the hydroxyl radical in the coma does not necessarily imply the existence of water on comets. 14.6. INFERENCES ON THE NATURE OF COMETS FROM EMISSION CHARACTERISTICS

    The assumption of ices as important bonding materials in cometary nuclei rests in almost all cases on indirect evidence, specifically the observation of atomic hydrogen (Lyman [Greek letter] alpha emission) and hydroxyl radical in a vast cloud surrounding the comet, in some cases accompanied by observation of H20+ or neutral water molecules. In addition, CH3CN, HCN, and corresponding radicals and ions are common constituents of the cometary gas envelope. These observations can be rationalized by assuming (Delsemme, 1972; Mendis, 1973) that the cometary nuclei consist of loose agglomerates containing, in addition to silicates (observed by infrared spectrometry (Maas et al., 1970)) and also water ice with inclusions of volatile carbon and nitrogen compounds.

    It has been suggested by Lal (1972b) that the Lyman a emission could be caused by solar wind hydrogen, thermalized on the particles in the dust cloud surrounding the comet. Experiments by Arrhenius and Andersen (1973) irradiating calcium aluminosilicate (anorthite) surfaces with protons in the 10-keV range resulted in a substantial (~10 percent) yield of hydroxyl ion and also hydroxyl ion complexes such as CaOH.

    Observations on the lunar surface (Hapke et al., 1970; Epstein and Taylor, 1970, 1972) also demonstrate that such proton-assisted abstraction of oxygen (preferentially O16) from silicates is an active process in space, resulting in a flux of OH and related species. In cometary particle streams, new silicate surfaces would relatively frequently be exposed by fracture and fusion at grain collision. The production of hydroxyl radicals and ions would in this case not be rate-limited by surface saturation to the same extent as on the Moon(for lunar soil turnover rate, see Arrhenius et al. (1972)).

    These observations, although not negating the possible occurrence of water ice in cometary nuclei, point also to refractory sources of the actually observed hydrogen and hydroxyl. Solar protons as well as the products of their reaction with silicate oxygen would interact with any solid carbon and nitrogen compounds characteristic of carbonaceous chondrites to yield volatile carbon and nitrogen radicals such as observed in comets. Phenomena such as "flares," "breakups," "high-velocity jets," and nongravitational [236] acceleration are all phenomena that fit well into a theory ascribing them to the evaporation of frozen volatiles. However, with different semantic labels the underlying observations would also seem to be interpretable as manifestations of the focusing and dispersion processes in the cometary region of the meteor stream, accompanied by solar wind interaction.

    It does not settle the mater but does at least allow more than one opinion. Also it is possible for the hydroxils to join up to make a H2O in the coma.

    It is important to know why there is water in the coma and the material the comet is made of, because we can not tell as an audience which is trhe more likely scenario.
    Some definative Data would be nice.

    • John says:

      This is a crucial issue Dave and one that the ESA must address rather than continually talking up the ice sublimation concept. They also need to measure the jets close to the comet surface to determine exactly what is being emitted. Until that is done all the possibilities should be discussed as you are doing. That is science. And it should be emphasised that up to now ice has never been identified on or in a comet.

    • John says:

      Dave, well done for drawing attention to the potential for the production of hydroxyl ions and neutral water molecules in the coma by the interaction of hydrogen ions from the Sun and oxygen ions from the comet rock. This obvious possibility has not been addressed by the ESA who have only talked about ice and sublimating water vapour. Are we to assume from this that they are not aware of other ways in which water could end up in the coma

  • John says:

    Dave, I replied to your comment about the production of hydroxyl ions and neutral water by ion interaction in the coma but my reply has vanished. Well done for raising the issue. In all the preamble to this mission this very strong possibility has never been mentioned by the ESA. They talk about nothing but ice and sublimated gas. Hopefully their blinkered approach will not stop them from drawing the obvious conclusions once the data has been collected.

  • Nhoj says:

    Dave, well done for highlighting the likelihood of production of hydroxyl ions and neutral water in the comet coma by interaction between hydrogen ions from the Sun and oxygen ions from the rock. Inexplicably this obvious possibility has never been mentioned by the ESA who relate everything to the ice and sublimated gas theory. Are we to assume they are not aware of other ways that water could end up in the coma.

  • John says:

    Dave, well done for drawing attention to the potential for the production of hydroxyl ions an neutral water molecules in the coma by interaction of hydrogen ions from the Sun and oxygen ions from the comet rock. This obvious possibility has not been addressed by the ESA who have only talked about ice and sublimating water vapour. Are we to assume from this that they are not aware of other ways in which water could end up in the coma.

  • John says:

    Sorry for all the repeats, Dave. There was some problem. The point is made anyway.

  • Primo says:

    Ok folks on random thing 🙂 can anybody tell me which radio station are these guys using as a background music? I need to have it! Funny how mind works, came to see some space stuff and now wondering about music 😉

Comments are closed.