CometWatch – 19 September

Four image NAVCAM montage comprising images taken in the early hours of this morning, 19 September, from a distance of 28.6 km from the centre of Comet 67P/Churyumov-Gerasimenko. For comparison, recall the OSIRIS image taken on 3 August from a distance of 285 km.

A mosaic, and the four individual frames are also provided below.

Four image montage of comet 67P/C-G, using images taken on 19 September. The four images are shown separated by black borders and there is some overlap between adjacent frames, so that some features appear in more than one image. Credits: ESA/Rosetta/NAVCAM

Four image montage of comet 67P/C-G, using images taken on 19 September. The four images are shown separated by black borders and there is some overlap between adjacent frames, so that some features appear in more than one image. Credits: ESA/Rosetta/NAVCAM

This beautiful view shows off a wide range of the comet's features: from the jets emanating from the ‘neck’ region, to the steep cliffs towering over both smooth and grooved terrain, and to the hundreds of boulders scattered across the surface.

Four image mosaic of comet 67P/C-G, using images taken on 19 September (rotated and cropped). Credit: ESA/Rosetta/NAVCAM

Four image mosaic of comet 67P/C-G, using images taken on 19 September (rotated, cropped and lightly contrast enhanced). Credit: ESA/Rosetta/NAVCAM

The mosaic has been put together using Microsoft ICE. This left a few small regions requiring slight exposure adjustments using Adobe LightRoom. The full image has then been lightly contrast enhanced to bring out the activity without increasing the background noise too much.

The original images are unaltered and can be used for comparison.

ESA_Rosetta_NAVCAM_140919_D

ESA_Rosetta_NAVCAM_140919_B

ESA_Rosetta_NAVCAM_140919_A

ESA_Rosetta_NAVCAM_140919_C

Comments

138 Comments

  • Dave says:

    Great picture with such amazing detail of many features, lots puzzling.
    In some places there are very bright spots, some tracing physical attributes like crater wall and some just balls. Are all of the white bits part of the this pictures film processing or are we beginning to see hot spots.

    The terrain on the top of the head looks like its been melted and then smeared across the head. There are some thick bits under the white plains that look like earliar deposits?
    This looks similar to Michael steinbachers Catastrophist geology on youtube for eu2014, where melted layers are deposuited from a close volcano (not from here though) or from a plasma erosion event. If so when the Comets heats up there will be a huge show.

    Its also great to look at rocks that are sitting on Flat planes and also on vertical planes in the same picture, of course a consequence of the comet shape but it still blows my mind, I guess now I can finally believe what my mum told me when I was 5, that the earth was round and that even the people on the btm can stand upright and not fall off. After all seeing is believing right?

    It must be difficult for ESA to coment on featuresas it is in print and their first gueses could be wrong, but it would be nice to understand how they view these strange features prior to more data coming in.

    • logan says:

      Agree with Dave. Prefer educated guesses to my random guesses. Reason being that data is huge. Brain needs models, even if they are only 'educated guesses'. Know will take years to digest, confront and cross link with past knowledge.

    • Solon says:

      "Are all of the white bits part of the this pictures film processing or are we beginning to see hot spots."

      Tough to say what is being imaged, as no information on what, if any, filters are being used. The sensor goes well into the IR, so I suspect that brighter objects are warmer, but we have no idea of the temperature range involved.

      • Erich says:

        As no update of surface temperature is present hot is rather as cold as 200 Kelvin.

  • rens says:

    Is that a crack across the neck?

  • Jason Rowberg says:

    Beatiful! Nice jets continuing on the neck. I don't know if it should or not, but that big crack running down the middle of the neck has me just a bit worried.

    • Erich says:

      Stop worrying its been there for quite a while, check older pictures of this region. Its there to find.

    • Alter Schwede says:

      A bit late for that as its beed there for quite some time, most likely before the arrival.

  • logan says:

    Love fractals!

  • logan says:

    Just the new perspective or there is less loosen material in neck area?

  • logan says:

    This sphere segments integrated smaller sphere segments in its formation.

  • Om says:

    I wish each and every feature of this heavenly body, including boulders, plains surface, different contrasting plains, and different deposits are explained by the experts.

    • Alter Schwede says:

      Om mani padme hum ॐ मणिपद्मे हूँ,
      May your wish be heard and come true.

  • Andrew Waugh says:

    I know I'm probably a little late to the party - have been following this mission since launch though.
    How awesome must it be the first to see these close up views of the comet! You must feel like astronauts! Great stuff.

  • Terran says:

    Very nice shot this time, background stars seem to be visible and that dusty-light-ray from the middle is wonderful.
    I wonder if you could tell me the sizes of a boulder on the surface. I'm troubled in realizing the actual size of these and the whole commet. I saw the size comparison, with Eiffel Tower and Rosetta and whatnot, but I still think I'd much rather get it if I could compare it with an object on the commets surface. Ofc, only if you can tell us and you know an approximate size yourselfe.
    In this picture I've marked 4 boulders I'd really be interest in with red cyrcles. (2 on the big part, 1 in the middle and one in the smaller part).
    http://imgur.com/cMM48Qu

    Many thanks, Terran

    • emily says:

      Hi Terran, I don't know the sizes of the specific boulders you've circled, but in general they range from large house-sized (say 10-15 metres across) boulders down to less than a metre. The comet itself is a little over 4 km across at its widest point.

    • Erich says:

      Each pixel has a size of 2.5*2.5 meters in this pictures, magnify and measure.

  • Herwarth Bernsdorf says:

    The comet looks somewhat like a lion! Fantastic!

  • Possible fracture detected on 67/P surface near the area of the jets
    https://scontent-a-mxp.xx.fbcdn.net/hphotos-xpa1/t31.0-8/10662043_776103785763975_2251574094801427603_o.jpg

    Thanks for these wondefull images. Credit ESA/Rosetta Team.

  • Stephan Andersohn says:

    Is that middle section more active than the rest? Why? There should be less energy from the sun that at all other surface.

    • THOMAS says:

      Unless it's not just a question of exposure to sunlight: perhaps the "middle section" (which everyone is calling the "neck") has been, and is still being, machined away by an electric discharge phenomenon which is naturally concentrated mainly on this central part of the comet (as being precisely the area where the difference in electric potential with that of the solar wind is expected to be maximum).

    • simos says:

      Perhaps the outgassing in the neck-region is caused by the internal friction forces there , due to the very irregular shape of the entire comet and its rotation .

    • Erich says:

      There is no clue for solar induced activity yet but as this has been observed before and is not continuos its origin is likely to be due to structural changes, call it comet quake.

      The comets two major parts are shifting due to gravity force and tidal influence from the sun.

      Its periodic time has speeded up 24 minutes since the last measurement. From about 12.8 hours per rotation to 12.4043+/-0.0007 hours per turn.

  • THOMAS says:

    What? "...smooth and grooved terrain..."? It rhymes (nearly) but what could "grooved" mean here? What might "grooved" terrain be? Surely you mean "stratified". It certainly doesn't rhyme but it's a more accurate description if we are trying to use previous experience to make sense of these astounding images.

  • THOMAS says:

    I'm talking in particular about the strata clearly visible in the rock foramtions in the lower part of the image, which are all pointing downwards and slightly to the left, at 7 o’clock). “Grooved”? By what, for example?

  • logan says:

    Right now I am data saturated.

    (It's good).

    🙂

  • Roger says:

    There appears to be a large crack near the base of the jets almost across the neck

    • THOMAS says:

      Except that we can't see the "base of the jets" at all: they are on the other side of what is actually just a ridge on the "skyline". (We are looking at the "neck" from the side and from 45° below). All the activity from the the hot-spots is unfortunately happening some way beyond that ridge, on the other side, much lower down and completely out of sight. The "large crack" is therefore apparently just a chance alignment with the direction of the jets.

      Interestingly though, it just happens to be aligned in exactly the same 7 o’clock position as all the other rock strata which are visible from top left to bottom right, over 4 kilometers (most clearly visible in the “lion’s” legs, of course, but also on its head, on its mane (top and bottom), on its rump and on the under-side of the belly). Now THAT makes you wonder, doesn’t it?

      • Erich says:

        Ok i got the picture of the lion, are Philae and Rosetta the prey? Small snack,

  • Haerwe says:

    Saturday 20 Sept 2014

    Emily, guess why NOBODY placed a comment on this page !

  • THOMAS says:

    Fantastically informative picture, once again. Many thanks!

    Shame that the totally exciting neck region where all the action is taking place lies tantalizingly out of sight on the other side of the ridge: we can see the jets shooting vertically "upwards", but not the precise place(s) on the neck where they're coming from. From less than 30 km distance now, surely OSIRIS should be able to show us that with something like centimetric precision.

    • logan says:

      Hi THOMAS, maybe I'm disoriented, but as of now only night side is missing.

      • logan says:

        Please check Errol sequence of ESA published media.

      • THOMAS says:

        Hi LOGAN. It’s true that orientation isn’t that easy when we’re getting pictures of the comet which are not only taken from different angles but also illuminated differently according to where the comet is in its rotation period.

        In my reading of this image, we’re looking at it from more or less behind the neck, judging from the fact that the shapes of the “head” and the “body” are much less distinct here than when we see the comet in profile, with that huge jutting chin, as in Thomas Appéré’s impressive rendering of the 02/09/14 NAVCAM image: https://www.flickr.com/photos/105035663@N07/15146280051/.

        As for the “night side” you refer to, it’s in the lower part of the current image, with sunlight coming down from the top (and slightly behind) Rosetta.

        • logan says:

          Thanks for your link THOMAS. In this high contrast my mind see a 'compacting' of the plasma flow just a few meters over the neck 'horizon'

        • logan says:

          A 'focusing' as in a CRT 'bulb'.

        • logan says:

          Yeap, we still need equinox and solstice info.

      • THOMAS says:

        What I think is “missing” from this image is the FRONT side of the neck which is on the other side of that ridge (the “lion’s” back) and which, for its part, is necessarily on the day side. This was already the case in the 02/09/14 NAVCAM image, as is clearly shown in Claudio Costerni’s equally remarkable rendering: https://www.flickr.com/photos/alpi-costerni/15149831901/.

        In that image, the white areas on the neck which those “jets” are shooting upwards from, far outshine the sunlight being reflected from the rest of the comet. It’s those hot-spots which are tantalizingly hidden from view in the current image.
        I can’t wait for OSIRIS to finally get round to showing us the close-ups of them we're all expecting (unless it’s the intensity of the energy being given off which is literally whiting-out all attempted pictures).

    • logan says:

      Have you considered the electric field being of form 'planar' and concentrating plasma flow?

      • THOMAS says:

        I think it's too early to start speculating about the precise nature of the electric fields at work here or, a fortiori, about the exact mechanisms which are driving both them and the resulting coma. To date, insufficient resources have been assigned to doing research into the role of electricity in space, given that mainstream cosmology has always stoutly denied the very existence of such a role.

        The top priority is first to establish that what is happening before our very eyes thanks to the Rosetta mission is indeed a case of electric forces machining away the solid rock which the comet is visibly composed of, and which, in so doing, has gouged out the so-called “neck” region. The alternative idea, based on the standard “dirty snowball” model, that the cool rays of the sun (very cool at that distance) are somehow causing hypothetical and, so far, totally invisible “ice” to “sublimate” is currently (no pun intended…) being put to a very severe test.

        The results still to come will presumably reveal the true reading, with all the necessary proof. I still hope that this is why, in a beautifully ironic case of poetic (and perhaps scientific) justice, the mission was called “Rosetta”.

        • Alter schwede says:

          I do not know of any sane denial against the electrostatic and even magnetic forces in large volumes of dust and plasma as they obviously do exist in theory and practical experiments even in smaller scales. As gravity is an extremely faint force in nebulas and comet tails the other forces are essential and by far NOT negligible. Tell me how clouds can form in a large building or cave as gravity has practically no influence at all in such a tiny scale.

        • Howard Haigh says:

          Youre saying that "electric forces machining away the solid rock which the comet is visibly composed of" and yet you also insist "it's too early to start speculating about the precise nature of the electric fields at work here". Comet 67P is considerably less dense than solid rock and the Rosetta probe is also less robust than solid rock and yet that's coping well with the environment it's in. The amount of solar radiation hitting anything at double the ditsance of Mars from the Sun, that's where 67P is roughly, is about 140 watts per square metre. That's plenty enough for Rosetta's solar arrays and is currently warming the almost perfectly black surface of 67P to about 220K at the so-called 'hot' spots. Solid carbon dioxide ice sublimates at 195K at one (Earth) atmosphere so in a near vacuum it will sublimate at far lower temperatures. Water ice also sublimates at low temperatures in a near vacuum, it'll certainly be doing so at 220K and the MIRO instrument on Rosetta is already measuring the amount of ice vapourising off the comet’s nucleus. If you could somehow gather it up and convert it to liquid, 67P is releasing the equivalent of two glasses of water a second.

          • THOMAS says:

            In saying that "it's too early to start speculating about the PRECISE (my bold) nature of the electric fields at work here", I was simply responding to LOGAN’s speculation that they might be “planar”. The reality of the electric origin of the observed activity will be proven as soon as OSIRIS starts releasing those eagerly awaited “smoking gun” images of the hot-spots. We shall then be able to start studying the PRECISE nature of the observed electric discharge phenomena.

          • THOMAS says:

            Your assertion that “Comet 67P is considerably less dense than solid rock” is presumably based on a premature announcement made by the ESA team some weeks ago when Rosetta was considerably further away, and which has not since, AFAIK, been reiterated or updated. The idea that this misshapen lump of rock would actually float on the surface of any of the world’s oceans with greater buoyancy than a champagne cork (i.e. with over two-thirds of its volume above the waterline!) beggars belief. Personally, I don’t believe in assumptions based on theories. I only believe in what I see. And what I see here is a 4 km-long chunk of stratified rock which would plunge straight to the bottom of any self-respecting ocean like a stone.

          • THOMAS says:

            Was it the same “sublimation” processes which were also at work in the still visible coma of Hale-Bopp well after it had passed back out beyond the orbit of Neptune in recent months? I think not: at that distance, the surface temperature of the Hale-Bopp nucleus is way below the 195K required to sublimate CO2 ice. There’s an obvious problem with your standard theory so there’s no reason why it should be right here either, especially since there is absolutely NO trace of ice on this comet, as mission scientists readily admit.

          • THOMAS says:

            As for the hydroxyl (OH) which has been detected by Rosetta’s instruments, it is not any sort of proof of the presence of “vapourized” ice but rather a proof of an electric discharge machining (EDM) process producing oxygen atoms which then immediately combine with hydrogen ions from the solar wind to produce hydroxyl. The “two glasses of water a second” idea is just a faulty extrapolation from a falsified theory.

          • Lynn says:

            Has anyone here attempted to compute the density of the comet. If the mass is 10^13 KG and the comet is the density of water, that would imply the size of a cube 10 KM on a side. Since the comet is considerably smaller that would imply a density of more than 5 times that of water. Would appreciate someone with more math to check my figures.

        • Chris Reeve says:

          Thomas, note the following from ...

          http://www.thunderbolts.info/tpod/2006/arch06/060207biela.htm

          "But of all the scientific details about comet Biela, perhaps none stands out more dramatically than the fact almost never mentioned—a jet forming between the two nuclear fragments when they were 2 million kilometers apart. In the purely gravitational and mechanical terms that astronomers have sought to apply to comets, this jet is inconceivable. But when we remember how inconsequential is gravity in the presence of the electric force, the improbability disappears."

          If this thing breaks apart, it has the potential to take Whipple's theory with it. Very exciting.

    • Alter schwede says:

      The Osiris resolution in the narrow angle camera is 2 cm pixel side per every kilometre of distance.
      30* 2 is 60 cm pixel side and 0. 36 m^2 pixel-area at 30 km distance.

      • Alter schwede says:

        The navcam resolution is about four time less.
        With the four stitched 500* 500 pixel images its resolution is about 8,5 cm per kilometre say 2,6 meter pixel side at 30 kilometre or almost 7 m^2 pixel area. Its obvious how much better osiris is concerning its resolution.

  • THOMAS says:

    We all see what we want to in a picture: in this one, has anyone else seen the lion with its small head at top left, its mane streaming out behind it and its rocky rump at bottom right? It even seems to be carrying a freshly-killed prey, hanging from its jaws… Amazing rock art!

  • logan says:

    Some areas at 10 o'clock of plasma jets origin really feel like 'low lands'. OSIRIS and other instruments will tell.

  • Robin Sherman says:

    Yet another fascinating picture. Like Thomas I find the crack in the lower neck region and the hint of another to the left of the top region of the neck highly interesting. The semicircular depression at about 5 O'Clock from the neck region and the stratification that spreads out through the body is surely a sign that this could well originally have been the collision point of two bodies.

    As I understand it the stratification is due to shock waves from collisions compressing the ices of the comet giving the illusion of stratified rocks. (There are no Rocks.) Certainly the alignment of these layers throughout the body of the comet would indicate one extremely large impact.

    Such is the detail of this picture there are also areas where the conglomerate nature of the comet can be seen, presumably from the slow accretion of the smaller chunks of ice over time as the comet was "growing" in its early life. The slightly different composition of the ices in these chunks (boulders) would explain why some remain exposed in such odd shapes all over comet. The flying pig on the far right of the main body is my favourite.

    Brilliant job by all those at ESA. Can't wait for the Flyby movie from DLR especially if they can use OSIRIS images from a 10Km orbit.

    • Solon says:

      "As I understand it the stratification is due to shock waves from collisions compressing the ices of the comet giving the illusion of stratified rocks. (There are no Rocks.) "

      Huh, I thought ices were already 'so yesterday', and collisions too. The eye of the beholder, I suppose.

    • THOMAS says:

      Hi, Robin Sherman.

      Sorry, but what I find fascinating/interesting in this picture is something completely different from what you think, with a completely different explanation. (Sorry too if I’m not the “THOMAS” you’re referring to – there’s also “Thomas”Appéré who posts his impressive renderings of ESA releases on this site).

      Where you see “stratified ice” (whatever that is – I didn’t even know the concept existed), I just see common or garden stratified rock, observed everywhere on Earth in the shape of what is most commonly termed “sedimentary” rock. But it has also been quite recently observed, for example, on Mars by Curiosity:(http://www.universetoday.com/97096/curiosity-sends-back-incredible-hi-res-views-of-mt-sharp/). On Mars, of course, the “sedimentary” origin of these stratified rocks, theoretically requiring a major role to have been played by water in their formation, is also a subject of fierce debate….

      Whatever its origin, stratified rock is a phenomenon which seems to pervade the various rocky bodies of the inner solar system we’ve acquired images of, without any need for hypothetical “stratified ice” phenomena which have as yet never been observed anywhere.

      You seem to be suggesting, presumably on the basis of the “dirty snowball” theory, that two pretty large lumps of ice located on a highly elliptical orbit somewhere between those of Mars and Jupiter might one day have collided, presumably at high speed. If this were even possible statistically, (by a vanishingly small chance of one in billions of billions), one might expect that the resulting objects would not “stratify” (by what physical property of ice, in that case?) but just shatter into untold trillions of ice-cubes, ice-shards or ice-you-name-its, never to be seen again.

      The comet we’ve just happened to visit on board Rosetta and photographed from many angles and in various lighting conditions, is most likely exactly what it looks like: a highly irregular, 4 km-long, chunk of stratified rock.

      As for the “semicircular depression at about 5 O'Clock” you refer to, I think you’ll find, on closer inspection, that it’s just a shadow cast downwards by a rocky outcrop.

      The boulders are also just rocks. No ice anywhere. No ice, no turtles, just rock “all the way down”…

      • Robin Sherman says:

        Do rocks have a density of less than 40% that of water?

        • THOMAS says:

          No, they don't. And this one doesn't either. The "40%" is as yet unconfirmed. Further updates from mission scientists over the coming weeks will prove that this one actually has a density far greater than water.

          • Denis says:

            Rocks do have density 40% of wateR.
            It could jut be very porous.
            Even on Earth, you have rocks with density lower than water (they actually float, you can try!), check 'pumice' on Wikipedia, there is a picture of one with density of 25% of water...
            Ok, these are volcanic rocks, but it's not so difficult imagining that low density rocks can form in a low gravity environment, if they can form in 1g gravity conditions.

      • Moo says:

        I don't know about you but there first picture I saw of this rock I thought the same thing. Sedimentary. I wanted to break them open and look for fossils.
        Honestly, I am a laymen. But a child could see how this got there.

    • morganism says:

      the whole body is very Pink Floyd !

      i agree with the impact compression model, and foresee that the neck area is outgassing more because of reflection/focusing of UV radiation on the graphite oxide exposed there, creating more hydroxyls.

      the "flying pig", and other standouts, should be considered to be remnants of impact crater compaction, that has eroded down the un-melted material around it, creating walls that finally crumble , and strew the "rocks" around the body.

    • logan says:

      Hi Robin. Had not seen that wave. Indeed look aligned.
      🙂

      • logan says:

        Have you considered it not being an im-pact but an ex-plosion signaling?

  • Joe says:

    Does any one know if ESA has determined the principle axes of comet and the components of angular velocity along these axes?

    I presume comet is mostly rotating about principle axes with smallest moment of inertia.

    Many thanks to all the people at ESA who worked together to achieve this "astronomical" feat.

    • Thomas from paris says:

      Interesting question indeed.
      Very nice to download those fantastic images. Does anyone knows where one can download the STL file of the comet (I would like to order a 3d print) ?
      ps: the 2 points where the axis of rotation intersect the surface of the comet would be interesting to know either.
      Thanks in advance

      • Erich says:

        http://blogs.esa.int/rosetta/2014/07/28/updated-comet-shape-model/

        This might help as it is possible to make 3D modelling from anaglyphs and all of it is there. The axis of rotation is hopefully correct.

        Other sources are available, most of them not as good as this one. It might also upgrade in the future so don't order your model too expensive. Once you have a model it is possible to drape it with pictures, there are some systems using colour printed wet gelatine to drape about any curved surfaces like a motor bikes gas tank.

    • Dertutenix says:

      Yes

    • Denis says:

      I would expect the comet to be rotating about its principle axis with MAXIMUM moment of inertia. That's the stable configuration (minimum rotation speed for a given angular momentum).

  • HoboSullivan says:

    If you look to the left of the crack, following the two parallel shadows that run through it, there's a smooth area and a feature that looks (to my untrained eyes) exactly like sand dunes.

    • Erich says:

      Looks like is the key word,

      Not much of a wind on this place in vacuum.
      The regathered material of dust around aphelion drapes structures underneath and these structures have shapes as some "naked " one has. Its done over eons of timespan. This is a cosmic time scale.

  • Alter schwede says:

    Talking about the moment of inertia, the comet is trying its best to change its shape. The frequent outbursts seeing so far have nothing to do yet with the radiation from the sun. Its two bodies are contracting due to the gravity pull and this results in quakes in the neck region. The spin of the comet has increased. The period time is today 24 minutes faster then the last measurement. It is preserving its momentum of inertia by increasing its angular velocity when contracting. Its a pirouette of a comet dance. The neck region is quite unstable as this is where a lot of grinding is going on between the two bodies. Tidal effects when getting closer to the sun will amplify this process.

    • logan says:

      Thank for the new data, Alter. This is going fast!

    • logan says:

      Whatever we had, we are going to have a 'contact' binary.

    • logan says:

      Grinding, how carefully chosen the word, not only the differential pressure around the perimeter, also the differential torque.
      😉

    • THOMAS says:

      Which "two bodies"? And what could be the nature and the cause of this "grinding" process?

      If your figure of "24 minutes" for the reduction in the comet's rotation period compared with "the last measurement" of 12.7 hours is correct (just your theory or insider information?), then this would be huge news.

      Nothing to do with "quakes in the neck region" though (comet-quakes?): should it be true, it would prove quite simply that the comet is slimming down alarmingly before our very eyes, resulting in faster rotation to conserve its angular momentum. To account for such rapid slimming (if your figures are correct), I would rather bet on a tried and tested electrical process called EDM (electric discharge machining) than on the unobserved sublimation of inexistent ice or on any sort of hypothetical “grinding” process.

      Whatever, the bottom line is that if 67P has indeed slimmed down by as much as 5% during the mere 50 or so days that Rosetta has been close enough to make such precise measurements, then it can hardly be 4 billion years old as standard theory would have us believe.

      • Erich says:

        The latest figure is 12.4043 +/- 0.0007 hours of period.
        Before it was 12.7 and in some publications 12.78 hours period. This is no inside information but needs some surfing to find and it is an official figure not older the a pair of weeks for public display. The resolution and its accuracy is the big surprise as it is what seems to be in parity of the capacity of the tools used. Before it was measured from a huge distany and now rosetta is orbiting. As we in the public only get what the pictures show us makes it a bit hard to retrieve accurate and valid measures. A lot of theoris and hypotheses can be made and to me anyone is as good as another one. There is no evidence that this comet has had this shape or companion for billions of yerars. Most certain its material has an age of billions of years but it has for sure a history of gathering an disposing of material. We will get a better knowledge of the nature of this comet soon enough. But this is only one of many and might be special or not.
        A ruff calculation of the force between the two bodies gives about 350 000 000 Newton +/- 33%, its prone to do some structural change to the 1/3 of water density material once in a while. The tidal effect due to the sun will kick in when it is closeer to aphelion. The sporadic outburst are most likely not due to the solar radiation of the comet.

        • Marco says:

          @ Erich I agree that such a change in the rotation is big news. It implies a big shift in mass converting gravitational potential energy to angular momentum (or possibly some other energy transfer) Such a big shift in mass is not evident in the exterior, and thrust forces from the jets are not enough to account for it I don't think.

      • logan says:

        Hi THOMAS. You are right, release of gas, dust and material DO alter the spinning, but compacting do too. Comets nucleus DO compact. Relax and enjoy this an event of our lives! We all are nothing more than chatting.

        And thanks to scientists that drop by and release some amiable advice.

        • logan says:

          (and do expand)

        • Albino black sheep says:

          Just a note,
          If the comet releases material, vapors or dust it will slow down its spin. If it collects it again it will speed up. If it gets hit by something it is complex and hard to predict. The contraction of the two bodies is in my mind due to the fact that the head part is delivering material to the neck region once in a while.

  • logan says:

    Does any scientist on board has a feeling of a conglomerate of 'marine debris'?

    • Alter schwede says:

      Lets call it cemented matrix instead, as marine indicates a lot of water an cement only needs some additives, some recipes even without water. The crack is present on all pictures the public has from this region so far. And its more then a single crack. Also its the sporadic active region. No comment concerning this , lets call it anomaly, has so far reached the public from ESA. If this is due to any reason is up to ESA to declare. The ESA knowledge base is not open source as we know by now, history will show who was the first to pinpoint some essentials.

      • logan says:

        In my 'star trek generation' mind think of not only dust and gas added to the layering. Remember 'Lucy on the sky with diamonds? As a child imagined the sky 'decorated' with an immense variety of crystals.

        • logan says:

          The electric fields, the magnetic fields, the pure ions, the bows, the frontiers among the stellar and nebula wind flows creating turbulences, both on the materials and the fields. Why not?

    • Dertutenix says:

      I don't think so

  • logan says:

    If -in mi humble opinion- science is the discipline of finding the patterns, and the pattern of the patterns, and so on, down to the bass patterns, the perennial; Then why this fascination with the word 'unique'? Truly is -if we believe in math- that as more science is accumulated less 'unique' phenomena our minds will perceive.

  • logan says:

    Is in the procedures a 'going back' over the 'sunny' pole if events develop too fast?

  • Dertutenix says:

    Its odd that so many scientist occupied with this comet release so little material of essence, we only get a few pictures an NOBODY at ESA dares to take a stand and make a few more or less qualified speculations or forecasts. Only the landing schedule and its target position is pronounced loud. Not even an updated figure of the comets mass or density is on Display and I'm sure this can not be a secret, so is its dimension that is said to be in the for kilometre range. Is it so hard to make a measurement with an accuracy better then a halve kilometre? The audience deserves a bit more respect.

  • Erich says:

    To me the Rosetta blog has a bit of fire and forget attitude.
    Perhaps this is the definition of BLOG? Correct me if i am wrong.

    One example is the very colourful map that is a poster. It was once presented and that was it. No follow up was made and therefore this part is in essence nothing more then the colorisation of a picture. The same with the dust collector plates.

    There are other examples to add to the list and anyone can do this by its own will.

    To my opinion a BLOG is a living document with a history update.

    What i want is to read more about the
    Map, dust samples, period of rotation update, reason of activity, improved accuracy of the figure of mass within 3% or better and the dimension of the nuclei say in 100 meter resolution. The moderator of this blog is surrounded by expertise, its like sitting on a goldmine of information.

    Historic docs and specs can be downloaded in quantum for those who are interested of any specific item. I have specs of instrumentation on board to such accuracy that essential parts can be analysed and copied.

    The news concerning the comet can only be supplied by ESA. It would be appreciated by me and a lot of others in the public if a few nuggets will reach our accounts of curiosity. Thank for the pictures but we all know what we get and what we could have had on top of that.

    Please and thanks in advance.

  • Erich says:

    I think the comet delivers only dust and vapours to its tails.
    When shortly thereafter it is exposed to the solar-wind and radiation, the tail diverges in a plasma tail and a dust tail.

    • logan says:

      This model make me think that non-ionized gas has his own path too.

  • José María Rivas says:

    Señores de ESA, yo creo qe ya es momento de bautizar al Cometa 67P. En la primera foto de este reportaje se ve claramente a un animal con dos cabezas ( a animal whith two heads. Many-headed animal). En la parte izquierda se ve claramente la cabeza de un león con melena incluida y en la parte derecha se distingue muy claramente la cabeza de un simio o de un mono. Por lo tanto se podría bautizar con el nombre "Cometa policéfalo mono-león". "polycephalous comet monkey-lion 67P". O resumido "monkey-lion comet 67P".
    Espero una respuesta oficial de este nombramiento con fiesta incluida si es posible. Gracias y Felicidades a la ESA por esta fantástica y apoteósica misión.
    Enviado por: José María Rivas Ortiz. España.

  • Erich says:

    Just a small note,
    Onboard the Philae are microphones that gives the opportunity to measure comet quakes or seismic activity.
    The sound will be well transmittet through a brittle body of low density. Someone calculate the speed of sound at this place and estimate if it is going to be like pinging a giant vine glass.

    • Erichalter Schwede says:

      Comet seismology is quite a new field. The neck region will be the source of sound and by measuring the time laps between S-Wave and P-Wave as well as its spectral distributions we might get lucky and be able to "look" inside the comet. Thats really great stuff and possibly the landers microphones are activated when it hits the dirt producing some noise and waiting for its echo. Even more fascinating then drilling a few inches into the comet. I hope a few experts in seismology are in the teams. The SW tools for this kind of project are well established and easily adaptable. Im not sure how complex the on board microphones are. Lets surf an check it out.

      • Robin Sherman says:

        I've seen quotes that the purpose of the microphones on Philae was to detect "comet quakes". It seems the team have struck gold again as the sense from the comments above is that there is great deal of deformation actively taking place generating large amounts of seismic information. This added to any CONSERT information should provide a detailed view of the inside of the comet.

        The huge amount of amateur and informed speculation created by this image across the web is surely a sign to ESA that at least an outline of the initial science conclusions and primary hypotheses going forward should be made available to a fascinated public. ESA's usually excellent outreach programme seems to be behind the eight ball on this occasion.

  • Jacob Nielsen says:

    On ESA's policies regarding public access i reread this:
    http://blogs.esa.int/rosetta/2014/07/16/access-to-rosetta-data/

    No, the blog is not hotwired to the Rosetta data stream. Yes, I still hang around here for the latest "fan poster". Eventually the discoveries will be shared with the public (or we can buy the primary publications)-
    Are we impatient here? YES we are.

  • Maxi says:

    Is it possible, using earlier photographs of the same regions (I think you have quite a stack by now), to try and identify any changes over time? I'm thinking of bits of the comet actually moving (granted, it's not very likely), or local variations in surface brightnes (say due to sublimation of part of the surface), that sort of thing.

    I assume this would be hard to detect and identify correctly, but either by matching the photos to a 3D model built from the earlier ones, it should be possible to do it with image processing I think.

  • Solon says:

    Making an assumption that the original material of the comet was/is silica, then what may be happening here is that there is a microwave-assisted chemical reduction taking place, the comet will become macroporous on its way to becoming a silicon aerogel. The ion tail is behaving as a plasma antenna, providing the charging and microwaves, the oxygen liberated combines with the solar wind ions to produce the detected OH. The comet should be eaten away each time it enters the increasing electric field of the Sun until it falls apart.

    • Erka says:

      That was something totaly new, making silica aerogel in vacuum with electricity. Wow

    • logan says:

      Hi Solon. This is bold. Would like to see it including relative strengths of phenomena. Beautiful because it is a model of full concert. Surprised of your 'energy-going-back-from-the-tail' proposal. Microwaves? Aerogel like? Why just one original material?

      • Solon says:

        I do not know if MIRO will be able to perform the appropriate measurements, but I think Rosetta would need to traverse the flux tube of 67P to perform the required experiments. Some of the work and publications of D.A. Mendis, such as "On the size of the cometary tail magnetic field" examine the nature of the ion tail and flux tube configurations.

    • logan says:

      Thanks a lot Alter. Understand and enjoy a significant part of it. I downloaded to read slowly.

      From it we can see than Phylae was not designed to attach to a primordial surface. (As just one example).

  • THOMAS says:

    Been waiting for a new update for four days now. The previous, already frustrating, mere trickle of images is apparently now turning into an extremely slow-motion drip…. Is it becoming that difficult to sift through the multitude of images being sent back from Rosetta to find just one a day which might be fit for public consumption without increasingly (and terminally) calling into question the dying “dirty snowball” model? Hopefully, the huge amounts of apparently compromising data currently being analyzed will one day be released. The truth will out!

    • Jason Rowberg says:

      THOMAS, I think you may be on to something. The ESA is probably compiling research they hope to release and blow everyone's mind. The last thing they want is a bunch of amatuers in the cloud figuring it out and spoiling the fun.

  • Lorand Lukacs jr says:

    I agree with Erich that the public should get more precize information and some scientific measurements from the instruments, PLEASE. As soon it is available to satisfy our intrest in this exciting Project. Or at least refer to links where this type of information are presented.
    As Erich stated: What i want is to read more about the
    Map, dust samples, period of rotation update, reason of activity, improved accuracy of the figure of mass within 3% or better and the dimension of the nuclei say in 100 meter resolution. The moderator of this blog is surrounded by expertise, its like sitting on a goldmine of information. Please forward this informationand also the grid structure (Latitudes and Longitudes decided along with a scetch of the comets position related to Earth and the Sun. Thank You!

  • Lorand Lukacs jr says:

    One other thing. Please state who is representing ESA or Partners of the people giving a statement in this Blog. Then we would know who gives "inside information" and who is NOT. Like myself I am an electronis engineer and Technical Writer with interest in Spaceflight and research. Thank You.

    • Albino black sheep says:

      I would prefere to get outside information as the information from the inside is far too sparse.

  • Erka says:

    I just had the bright idea that there could be a possibillity to analyze the comets head with the seismic instrumets on board Philae and then make a modal analysis of its tremors, to moddel this in a faster manner its preferably done with a 4D finite element methode.

  • Albino black sheep says:

    All the instruments on board this mission and all the experiments performed by experts and all and all and all plus some money results in statements like " the comet is about four kilometer wide and black ".

    But Rosetta will get a lot closer and Philae will land and more experiments by more experts wil be performed and the answer they might give us could be like this:

    " It is not made of cheese."

    • Denis says:

      Rosetta is going to be in orbit around the comet for another year at least. In my opinion, it is pretty dumb to expect conclusions on the comet composition, origin,.... after one month there.

  • Erich says:

    Calculate;
    If the mass of rosetta is known
    If the orbit period time of rosetta is known
    If the shape of the orbit of rosetta is known
    If its delta velocity in its orbit is known
    If the spinn axis and period of the comet is known
    Then;
    To calculate the mass of the comet is easy
    To calculate the gravity field variation of the comet is easy
    To calculate the mass distribution of the comet is easy
    Then;
    If the physical dimensions can be measured by the onboard instruments, say cameras and radar.

    Then all this information can be presented in a form that is more then just a rudimentary statement about this big an heavy and black and faar away and so successful and thanks a lot.

    If experts at ESA do not have the knowledge to do this job i am more then willing to assist the best i can and promise to get the job done as this is elementary old Newton and simple calculations.

  • THOMAS says:

    Instead of just twiddling my thumbs during the long wait (coming up to five days now and still counting...), I just read through the ESA policy statement that Jacob Nielsen linked to above (many thanks! – I hadn’t seen it) and the almost unanimously indignant comments it generated.

    But I think the case is perhaps even more serious than the various contributors to that post imagined a couple of months back. In reality the “protecting academic careers” argument may go beyond just ensuring that the researchers involved have a six-month head start to publish their cutting-edge papers. Maybe the reason they need to protect their careers is that the constant stream of data they are seeing being sent back by ROSETTA is, to their increasing dismay, definitively falsifying the “dirty snowball” comet model and instead confirming the competing “electric comet” model. Perhaps they actually need those six months to try to work out how to put a brave face on it and save their careers by operating the required U-turn. There are probably many other mainstream cosmologists in the know who are also getting seriously worried in the same way.

  • logan says:

    Hi Linn. You are right about that 1x10^13 mistake. Is the source Wikipedia?

    • Lynn says:

      Logan
      The RSI team has estimated 10 trillion KG +/- 10% or 1X10^13 KG. If one cubic KM of ice has a mass of approx 1 trillion KG (1x10^12 KG), then if the comet were solid ice, it would have a volume of 10 cubic KM. We can estimate the volume of the comet (4X2.5X2.5 +2.5X2.5X2.5 KM) at around 35 cubic KM. That would give the density 10/35 or about 1/3 the density of ice. What is your estimation?

      • logan says:

        ...a volume of 10 cubic Km (If water density), not a cube 10 Km on a side. My mistake was there, Lynn.

        🙂

      • logan says:

        Hi Lynn. Not Legos. You can throw away a third of that volume.

    • Erich says:

      Entering the orbit time 13.63 days at the radius 28500 meter then the mass of the comet is 9.88E12kg.
      The orbit figures are presented by ESA and using Kepplers law gives the mass, the mass of rosetta is small and not put into the calculation. If this is done as well it ads so little that it is of no concern.

      M=(4*pi^2*r^3) / (.G*T^2)
      G=6.6726E-11 N-m^2/kg^2
      G is the universal gravitational constant

      If the volume of the comet fits in a 4000*3000*2500 meter box (3E10m^3) then its density is about a third of water (329kg/m^3). If someone that has made a 3d model can give me a figure of its volume if its maximal length is approximated to 4350 m i can calculate a better figure of density.

      Unfortionately i have no accurate figure of the volume but it is reasonably close. In feneral it fits the bill and if ESA would be so nice and put in more accurate figures this would be appreciated. Its really about time now!

      • Erich says:

        The comet might have a volume of 21km^3.
        Its maximum lengt can be closer to 4,5 km.
        With the mass of almost 10 giga ton
        the density is then almost the halv of water.

        For sure is tha ESA have figures that are a hundredfold better in accuracy then i can extract.

        So far the periode time and mass are accurate enough but the figure of volume is to uncertain.

  • Dave says:

    ESA and Emily,
    Please get someone to release some information.
    The mission is fanatastic but its like we are the ones in outer space.
    There must be some things you can tell us that dont compromise your mission or future plaudits, eg

    What is the composition and structure of the captured dust, there should already have been some analysis by now.
    Is the dust consistant with born in a freezing rubble field, or does it show signs of heating ie not born in the icy wilderness.
    Is Rosetta really bathed in water? or is it bathed in OH hydroxils of unknown origin?
    What is the latest estimate of gravity? and how solid is the comet?
    The instruments that can check comet structure beneath the surface?, HAVE THEY DISCOVERED WATER ICE and if not what is main material of the comet?
    What do your instruments tell us about the surface of the comet, if there is no surface ice, what is the surface material?
    Have you now got some better temperature mapping that you can let us see? particularly where erosion is occurring?
    Some of the latest pictures show suspicious white outs, are all the white outs we see from pushing the pictures to get a contrast or are we beginning to see hot areas?
    The big so called crack in recent pictures, can you see if this a crack, or is just some deposited material laying over a smooth area?

    This looks like a lot of questions but I am sure you already have this information, please release it so that the Blog can get more factual and more interesting. With no pictures comming, surely data is not to much to ask. We will still buy the official pictures and literature anyway, but the release of that could be years.

    All the best for continued success with the mission

    • THOMAS says:

      Hear, hear!

      (I'd like to add in one or two more questions but I'm making my comment deliberately short, because my last one - and perhaps two - were censored).

      Hoping for some answers...

  • ethanol says:

    Thomas: the idea that they have been navigating this spacecraft through a series of progressively lower orbits after so significantly mis-measuring the comet's mass is not plausible. Furthermore, the latest post (about the night excursion) contains the diameter and period of the most recent orbit. I plugged those parameters into a orbit calculator, and got a result very close to the reported 1.0 x10^13 kg. You cannot mass objects just by looking at them.

    • THOMAS says:

      Fair point, ethanol. I had the same thought when reading through the latest post. But I still trust my eyes and I still wonder how such an apparently solid rocky-looking object can in reality have the density of a champagne cork as the calculations seem to suggest.

      And I still believe in the electric model of comets rather than in the "dirty snowball" one. So my best guess is that the electromagnetic fields surrounding the comet (whose existence is denied by standard theory but required by the electric model) are exerting an attraction on the probe which is an additional, undetected parameter to that of gravity. Flight mission controllers are thus able to calculate accurate orbits from the mass readings they are getting, without needing to worry about whether gravity is the only force being exerting on the probe or not (since their calculations effectively work).

      I hope you will admit, as a logical corollary to all this, that if intense electric activity is indeed observed on and around the comet (as those jets emanating from the hot-spots strongly suggest), and if the substance of the comet is shown to be any type(s) of rock, then this would be confirmation of the ideas I'm putting forward and would necessarily require a complete paradigm shift.

      I am still intrigued by the fact that absolutely no close-ups have yet been published of those hot-spots on the neck, whereas they are by far the most unexpected finding of the mission so far and surely worthy of the utmost attention in establishing the real nature of comets.

      • THOMAS says:

        Sorry, in second paragraph above, it should have been "are exerting a repulsive force on the probe" rather than "an attraction". The principle remains the same.

        • ethanol says:

          Ah, so the disagreement between your theory and the available evidence is actually the unexpected result of another aspect of your theory, mediated in this case by vaguely defined repulsive electromagnetic fields.

          • THOMAS says:

            It’s as you like, ethanol.

            I pointed out a few days back, in another comment on another thread of this blog, that what is “vaguely defined” in terms of the electric theory of comets (and their wider environment) is so only because no research has been allowed to be done in this field “in situ” given the stark denial of the very role of electricity in space by the mainstream community, which controls research funding.

            Personally, I just happen to believe in what I see rather than in what I’m told (that’s incidentally why I chose the avatar « THOMAS » which also happens to be my second name). If you really believe that this object would actually float higher on any of the Earth’s oceans than any vulgar champagne cork does, then I think it’s high time you should also start questioning some basic mainstream assumptions and the resulting theories.

            If we are to set absolutely no store by the extraordinary photos being acquired of this clearly rocky (and not cork-like) object, then why on earth did we even ever decide to send Rosetta there in the first place? I thought the main idea was to get close-up pictures. We have done, and I assume you’ll agree that it’s been shock and astonishment all the way down for mainstream cosmology (or do you still think this thing looks like a dirty snowball?) The truth is that the pictures are a huge embarrassment for standard theory and that there is something evidently (“evidently” in the sense of “evidence”) wrong with it…

            In any case, “the jury is out” (and probably will be for a few months or even years, given the potentially negative consequences of adverse findings for the majority of mainstream cosmologists). But when it eventually comes back in and if the evidence is presented fairly, there are a whole load of huge surprises in store for everyone. In the light of what we have already seen, we can all be sure (whatever our prior beliefs) that comets are certainly not what they have always been touted as.

  • The mass is very close to 10.5 giga ton i think within 2 %
    The volume i still don't get better then about 21km^3
    For now thats the best i can do.

  • Ross says:

    ESA, please share your data with the public. If you truly want to connect people with science, putting a smiley face on a cartoon space probe isn't the best way to do it. Engage the community with the beautiful images and fascinating observations you're collecting, in a bit more real-time. Don't worry, you still get credit for the science!

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