A preliminary map of Rosetta’s comet

Scientists working on images of comet 67P/Churyumov-Gerasimenko have divided the comet’s surface into a number of different regions based on their morphology, revealing a unique, multifaceted world.

Several morphologically different regions are indicated in this view, which is oriented with the comet’s ‘body’ in the foreground and the ‘head’ in the background. Credits: ESA/Rosetta/MPS for OSIRIS Team MPS/UPD/LAM/IAA/SSO/INTA/UPM/DASP/IDA

Several morphologically different regions are indicated in this preliminary map, which is oriented with the comet’s ‘body’ in the foreground and the ‘head’ in the background.
Credits: ESA/Rosetta/MPS for OSIRIS Team MPS/UPD/LAM/IAA/SSO/INTA/UPM/DASP/IDA

The map and new high-resolution images from the OSIRIS instrument were presented during the Rosetta special session at EPSC today.

With various areas dominated by cliffs, depressions, craters, boulders or even parallel grooves, 67P/C-G displays a multitude of different terrains. Some areas even appear to have been shaped by the comet’s activity.

This preliminary analysis provides the basis for a detailed scientific description of the comet’s surface, but a substantial amount of work involving more detailed OSIRIS images and data from other Rosetta instruments lies ahead to determine what each region represents in terms of their composition and evolution. One recent image from the OSIRIS narrow-angle camera is also shown here.

Jagged cliffs and prominent boulders are visible in this image taken by OSIRIS on 5 September 2014 from a distance of 62 kilometres from comet 67P/Churyumov-Gerasimenko. The left part of the image shows a side view of the comet’s 'body', while the right is the back of its 'head'. One pixel corresponds to 1.1 metres. Credits: ESA/Rosetta/MPS for OSIRIS Team MPS/UPD/LAM/IAA/SSO/INTA/UPM/DASP/IDA

Jagged cliffs and prominent boulders are visible in this image taken by OSIRIS on 5 September 2014 from a distance of 62 kilometres from comet 67P/Churyumov-Gerasimenko. The left part of the image shows a side view of the comet’s 'body', while the right is the back of its 'head'. One pixel corresponds to 1.1 metres.
Credits: ESA/Rosetta/MPS for OSIRIS Team MPS/UPD/LAM/IAA/SSO/INTA/UPM/DASP/IDA

As both 67P/C-G and Rosetta travel closer to the Sun over the next months, the OSIRIS team will monitor the surface looking for changes. While the scientists do not expect the borderlines of the comet’s regions to vary dramatically during this one passage around the Sun, more subtle transformations of the surface may nevertheless help to explain how cometary activity created such a breath-taking world.

Next weekend, on 13 and 14 September 2014, the maps will play a key role as Rosetta’s Lander Team and the Rosetta orbiter scientists gather at CNES, Toulouse to determine a primary and backup landing site from the earlier pre-selection of five candidates.

 

 

 

Comments

55 Comments

  • pikarl says:

    A map without a legend?

    • Bruce Arnold says:

      No legend, no scale, it is an illustration, not a map: I am a map make, I expect in the future to see a real map of this comet.

      • Pete says:

        The article makes it clear that "a substantial amount of work involving more detailed OSIRIS images and data from other Rosetta instruments lies ahead to determine what each region represents in terms of their composition..."

        • Joe says:

          And what are the terms for this map? I' can't wait to know more about this!

  • roberto nesci says:

    the comet rotates in 12 hours: centriful force may throw roks away from the comet surface if stronger than gravitational attraction. Is there any place on the comet surface where this happens? if so, such place should be free from stones or even dust..

    • No. The most recent mass determination I've seen is ~10^13 kg. Escape velocity is therefore ~0.8 m/s (assume a distance of 2 km from a 10^13 kg point mass). The rotational acceleration at the equator is about 0.3 m/s. So the comet doesn't spin fast enough to lose material.

      • Kaido Tiigisoon says:

        Moreover. I think it needs to be pointed out that the comet may have been spun fast enough to shed some material. However, this robs the object the spin energy, so that it slows down until the speed is slow enough to avoid throwing stones.

    • Derek says:

      Nah body is 1 KM rotation takes 12 h - that does not provide enough juice to throw rocks away not even dust.

      • Steve Kasian says:

        "...not even dust"? That doesn't really make any sense, as any material would leave the object's surface at the same time and velocity, regardless of it's size, in a vacuum. Newton's 2nd Law...

  • Jim Nelson says:

    I'm curious about this comet's history. My searches aren't turning up much other than it's orbital statistics. My main wonder in spite of knowing how notoriously unpredictable comets can be is how much of a tail it might get based on past performance.

  • THOMAS says:

    It is indeed a pity that this beautifully colour-coded map has no legend to enable us to decipher the code. A shame too that the image was taken from such a angle that the most intrinsically intriguing region of all, the neck, which is the source of the majority of the observed "outgassing"/jet/discharge activity, is completely hidden by the body.

    Hope there'll be more pictures on the way showing the neck region. Or did the energy apparently pouring out of this region actually prevent OSIRIS from taking pictures of it due to white-out?

  • Steve Colclough says:

    The shape of this comet reminds me of a rock my grandfather found. It too had the shape of a rubber duckie. He had it sent to a local university for examination and it was determined that the "head" was a rock that had been dragged by the advancing or receding ice during the iceage and the "body" was the debree it collected. Maybe the "head" of this comet struck a glancing blow to another larger object causing some of it to stick to the rock giving comet 67P/Churyumov-Gerasimenko the rubber duckie shape.

    • Errol Coder says:

      I believe it had been previously said that the comet was originally two separate objects. That at some point in its geological history, the two objects, "head" and "body" fused at the "neck" region. If you look at the recent VIRTIS map seems to indicate different temperature patterning of the head and body. This might be an indicator of the above possibility if they were two separate objects at one point.

  • Steve Colclough says:

    Correction to my last debree should have been debris. Sorry

  • Bill says:

    Geomorph. Makes the world go 'round.

    No need for a legend, we write as we go along... 🙂

    --Bill

  • Will you release 3d models or pointcloud data at some point? It Would be fun to play with.

  • Jacob nielsen says:

    Anyone noticed the pixel wide deep black rod-like structure opproximatly in the middle of the bright area of the hires osiris image. Anyone able to tell if this is an imaging artifact? Does not appear to be a randomly straight crack/ shadow feature. Other apparent artifact appear as deep black dots a few pixels wide. Just can't stop gazing at this strange mountain or gletcher or whatever...

  • Erich says:

    No there is no such place.

    Google for an online gravitational force calculator.
    Enter the comet mass in this calculator to 1e13 kg
    Enter the rock to 100 kg
    Enter the distance to the center of mass to 2000 m
    Note the force of gravitation

    Google for an online centrifugal force calculator
    Enter the mass of the rock to 100 kg
    Enter the radius to 2000m
    Enter the angular orbital speed to 12.7 hour per turn
    Note the centrifugal force

    Compare the amount of the two forces and realize that the gravity wins

    Do all over again altering the radius only and try with 3280 m and realize the this is about where the two forces are equal. You may call this geostationary orbital position meaning outside this place at the same angular velocity peaces fall apart. Or if the comet would be the size of almost seven kilometer diameter and the same mass as present then it actually would loose some of its boulders.

  • Erich says:

    The map has a lot of nice colors but that is all i can say.
    What the colors represent is not told and therefore not understandable to anyone of us outside ESA.
    Please update the map with meaningful information.

  • Erich says:

    Will the native aliens in the green zone be able to travel into the brown zone without a visa or is the like the EU so they can go cross the borders at their own will? Are there duty free zones available?

  • eSpace says:

    What a fabulous OSIRIS picture! It feels like you could reach out and touch the surface even though Rosetta is 62 km out. I'm going to have to buy a bigger, better monitor now so I can take in the whole hi-res pics without scrolling. Sure looks like snow/ice accumulation in the top left. Thank you for sharing!!

    • THOMAS says:

      It's certainly not ice or snow, otherwise the legend would have mentioned it, whereas they only talk about "jagged cliffs and prominent boulders". It has already been clearly stated by mission scientists that no trace of surface ice has yet been detected anywhere on the comet. The features you interpret as ice are simply examples of those highly intriguing smooth patches that can be seen in other images elsewhere on the comet, most notably in the enigmatic neck region (but also on the underside of the body in the colour-coded image at top). There seems to be a strong correlation between these smooth areas and the comet's "outgassing"/jet/discharge activity .

  • Tractor says:

    Scientists working on images , that is clearly not clear at all what their work was good for. Can someone enlighten me or is this secret information protected by proprietary rights. Im just curious.

    • logan says:

      We can just throw away tags and terrestrial allusions on what we see or believe to see. Scientists have to 'chew' more carefully before doing that. It is not secrecy.

  • Tractor says:

    Whatever the meaning of the map is and what useful information it holds within is washed away by the great new osiris high resolution picture with a detail recognition size of about one square meter. THAT is information anyone APPRECIATES.

  • LeoDP says:

    "A body"...
    "A head"...
    Then you confirm it!
    It's a greyish duck!
    Was, as it is already turning outo bright swan.

  • Jeff says:

    Maybe it's my imagination and a grainy photograph, but some of that looks like sedimentary deposits.

  • Elvee Kaye says:

    Where is the ice? I was promised a world made of broken-up rock and chunks of ice, but it really looks like just another asteroid. So much for the "dirty snowball" hypothesis. Time and again, it has proven to be wrong, yet nobody mentions it. Why not?

    • Bancor says:

      Because not!

    • logan says:

      We still have our jaw down.

    • Errol Coder says:

      The lack of surface ice may have been a recent event. Abviously, even looking at the recent Very Large Telescope image of the comet, that it does in fact have a tail. I am not sure if there is any spectroscopy done recently on the tail that reveals if any of it is water ice or gas. But, there appears to be current jets present which sublimates sub-surface particles. It was indicated that the ice surrounding these dust particles that composes the majority of the tail may evaporate and helps form the existing tail. Any proof of this anyone?

      Most of the existing water particles may have derived from the sub-surface regions.

      The Very Large Telescope image of the tail does appear to be redder then the nucleus. But, can't locate an spectroscopy of the tail itself.

  • mishari says:

    Why all comets, moon etc grey colored?

    • Erka says:

      5 billion years collected stuff makes a mess.
      Organic molecules contain coal and the surface of a comet receives hard radiation , this radiation strips molecules to the bone leaving coal, some molecules are like tar. Most minerals are dark. Iron is dark too. Dust that is not transparent absorbs light better then reflecting it. An so on.

  • Erka says:

    Sedimentation can not be happening on the comet as almost no liquids are present in vacuum and those existing are so rare that they are soaked up. The closest possible way to get layer structures in a dry place like this is due to bombardments creating huge dust clouds spreding all over the place and also the orbital induced evaporation and sublimation cycles can create layers. Sometime shadows look like deep cracks, you must sort those away your self. To my eyes trails of downhill rolling stones are present and as this is in low gravity the structural integrity is about as brittle as a castle of sand.

    • logan says:

      I like to believe that the solar bow produces the necessary turbulence to do this 'layering'.

    • THOMAS says:

      I don't think anyone is suggesting that sedimentation is "happening on the comet".

      If what we are observing in the Osiris images is finally confirmed by further, forthcoming images as proof of sedimentary rock formation, then it will necessarily follow that the comet has a very different origin from the one that the standard "dirty snowball" model has imposed on us ever since Fred Whipple first suggested it over 60 years ago (on purely theoretical grounds, and for want of the pertinent, close-up, gainsaying images that Rosetta is now providing us with).

      Should this happen, comet 67P will hopefully no longer be touted as a pristine 4.5 billion-year-old remnant of the birth of our solar system visiting us from its outer confines but, instead, be described more scientifically as a rather large chunk of rock which was ripped bodily from one of the inner rocky planets by a catastrophic event in the indeterminate past. Maybe we’ll even be able to determine which planet it was torn from and from where on the planet’s surface (a bit like the various authenticated Martian meteorites which have been found on Earth…).

      For the moment, everyone is seeing things, as you put it "to my eyes" (myself included, of course): it is indeed very difficult to put aside one's own mindset to try to see things, even fleetingly, from an opposing angle/perspective/paradigm. I sincerely hope and believe, however, that the extraordinary present and upcoming images from Rosetta will facilitate and accelerate the sort of much-needed paradigm shift that was achieved four centuries ago by Galileo’s similarly controversial pictures of the moons of Jupiter (but without the ensuing witch-hunt this time round…).

  • Mark Zambelli says:

    Oh my, what an amazing Osiris shot! Boulders (some with trails), smooth swales, jagged peaks, whole lineated areas pretending to be 'sedimentary' layers... awesome image. Can't stop staring at the hi-res (and imagining the upper limb over on the back of the head with that crest resembles a Western-film-set!, just add a few cacti and joshua-trees (grin)).
    Superb, thankyou for sharing

    • THOMAS says:

      On closer inspection, I think you'll find that what you interpret as "trails" are simply the long shadows cast by the boulders, give that the sunlight is coming down from the top of the image (as confirmed by the light/shade patterns in the rest of the image, including the division of the boulders themselves into light at top/dark at bottom zones). It's certainly not a Rolling Stones event!

      I agree, though, that it all looks very much like something from the American Far West, complete with the canyon dividing the two outcrops. (Maybe Rosetta just isn't close enough yet to see the cacti...). It would be hard to imagine a rockier-looking environment (complete with evidence of apparent sedimentary rock formation), even if the picture had been taken in the Grand Canyon itself!

  • Kamal Lodaya says:

    In the Osiris image, the edge of the "head" part seems to have a curious pattern of structures "standing up" so that the edge looks like a wall put up by some artist. (I know this isn't precise but I don't have the language of a geologist.) Does this suggest that some part has broken away from here, or is this the wall of the crater on the head that we have seen in other views?

    The pictures I have seen of Philae make it look a bit like a bulky refrigerator. Maybe something like a motorcycle next time to roll down the hills!

    Best wishes. Looking at this image I suspect the landing will be tough going.

    • THOMAS says:

      Interestingly, the "standing up" structures seen starkly jutting upwards against the black of outer space at the top of the image in a one o'clock position are themselves perfectly aligned with the numerous long, straight,parallel fissures to be seen at many different points from the very top left to the very bottom right of the background outcrop (which are presumably many hundreds if not thousands of feet distant from each other - we don't have the scale) but perfectly parallel to each other in a one o'clock position throughout. Given the size and the consistency of the phenomenon, they look like the strata which on Earth would immediately be categorized as a form of sedimentary rock formation.

      (The perfect alignment of these strata and the truly large scale of them is even more evident in the henceforth famous 3D Osiris image which shows the big picture of this same region :
      http://www.esa.int/spaceinimages/Images/2014/08/Rosetta_s_comet_in_3D ).

      I don't see what sort of physical phenomenon could have produced the same sort of large-scale, strikingly geometric formation on either a dirty snowball or a porous rubble pile.

  • Paul says:

    A bar scale would go along way to help put the size of the comet into perspective... a small extra step that would really benefit the non-astronomical community and casual viewers.

  • logan says:

    There a lot going on!
    Please feed the fish at some moment of rest.

  • logan says:

    Hi Kamal. It looks to me as a 'relatively' fresh fracture too. Don't think Rosetta Team dare to attach Philae there. Scientifically amusing that zone.

  • logan says:

    In such a low gravity they could be 'aggregation' deposits, too. 🙂

  • THOMAS says:

    I refer above, in my comments on recent posts by Mark Zambelli and Kamal Lodaya, to what appears to be a sedimentary rock formation making up the underside of the "head" region of the comet (i.e. on the very broad "chin" area as seen from below). It would certainly have been immediately categorized as such if it had been observed on Earth (particularly in the light of the astonishing Osiris 3D image:
    http://www.esa.int/spaceinimages/Images/2014/08/Rosetta_s_comet_in_3D).

    Has anyone seen any similar images of the cliff-face on the other side of the "neck" which divides the head from the body (as if the Osiris image above had been taken from the opposite side of the canyon)? If the upper "chest" side of the "body" facing the underside of the "chin" were to show some sort of corresponding rock strata, aligned in the same direction, that would start to become even more intriguing...

    If no such images exist yet , perhaps Osiris will be coming up with them in a few days time. I can't wait!

    • Dave says:

      Thomas,
      that could be sedimentation, or is it just erosion marks from the ejection of dust and gas from the neck area.? on the picyures showing the jets, it appears that the jets brush against the the underside of the neck.

  • We would like to print a 3D model of the comet. I am assuming esa already did this to help determine the appropriate landing site. Where can we get a copy of the 3D data to send to a desktop printer?

  • Alter schwede says:

    I tried to find a wood with the same density as this comet and balsa is 50 % lighter, bamboo is a hollow grass but fits quite well to the 0.3 kg/l all others are a lot heavier. Can anyone else but me grasp that the comet is sort of very dense thermal insulation material? Polystyrene foam has 0,1 kg / l but no vacuum inside, the comet actually due to low density AND vacuum does a better job of thermal insulation.

    • logan says:

      Hi Alter. Think you are right about the very good insulation. But also imagine that outside is lighter than that, akin to puff pastry bread, and inside is denser than that. What is it inside, besides water? That's the amazing science that is going to happen here 🙂

      • logan says:

        Don't forget that as plasma atmosphere is increasing, heat transfer too.

  • Leo Vuyk says:

    The origin of the main craters at Comet 67p C-G.
    If we assume that all circular craters at the surface of comet 67P are originated by two aligned gravitating Dark Matter point sources, then we may get an impression of the inner structure of the comet responsible for the shape.
    http://www.flickr.com/photos/93308747@N05/?details=1

  • emily says:

    Watch from about 15:00 in the landing site selection announcement (http://www.esa.int/spaceinvideos/Videos/2014/09/Replay_Rosetta_landing_site_announcement) for a few details about the colour designations used for mapping 67P/C-G. To summarise based on what was said there, we learn that brown = cliffs, bright green = basal unit, cyan seems to contain material that could have been redeposited on the surface from elsewhere to create smooth regions; light green = possibly some light activity; pink (not seen in this view but refers to the neck) = highly active.

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