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Space Science

Deep Impact Mission Reveals Comet Ice 54

Posted by Zonk from the good-job-tiny-space-probe dept.
Ant writes "New Scientist reports water ice is present on the surface of Comet Tempel 1." From the article: "The finding was made via observations from NASA's Deep Impact mission. This is the first direct detection of exposed water ice on a comet. The mission's science team says the water ice is present in surprisingly small amounts, covering less than 1% of Comet Tempel 1's surface. The finding suggests the comet's surrounding cloud of gas and dust may largely be fed by underlying ices, rather than by gas streaming off its surface."
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Deep Impact Mission Reveals Comet Ice More

Deep Impact Mission Reveals Comet Ice

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  • It's space-debris, but not as we thought we knew it.

    There's a comet in the skies these days, which will be closest in a couple months. Unfortunately, I seem to have grabbed the wrong printout before leaving home. :-(

    • I'm trying to think of an elegant way to BOTH hit a comet with a slug of metal and then to land a rover on it shortly therafter. So far, I can't think of a good way to do it. The high energy of comets makes it easy to slam things into them at high velocity, but tough to rendezvous with.

      • I know. As you approach the comet, let go of a rover/lander, which will then power off on its own toward the comet to set up for observation. On the probe's fly-by, you launch your detonator/kinetic probe to slam into the commet tearing up the comet a bit. The probe will watch from above, and the rover/lander will watch on the surface. You could even have the rover/lander circle the commet while the probe assaults it, and then have it land and take readings.
        • >the rover/lander will watch on the surface. One important thing to plan: make sure the probe doesn't hit the lander! On the other hand, if it does, you'll get the eternal glory of staging the first extra-terrestrial traffic accident! ;)

        • The problem with this is that the rover would need it's own propulsion stage with a very high delta-V. This is costly and requires lost of extra mass. We are talking ~10^4 meters per second. Play with the rocket equation and reasonable ejection velocities, and you'll see what I mean. For a reasonable Isp of 300 seconds and no stage mass, you get a payload mass fraction of 3% for 10 km/sec delta-V. What that adds up to is it would have to be a really tiny rover, which has inherent problems. Maybe with

      • Let me try to solve your mental anguish j/k :)

        Heard about the Stardust mission right? They collected particle samples in aerofoam and then slammed it into earth on the return without disturbing/destroying said particles.

        So make your slug of metal hollow, insulate the rover with as much aerogel and shockabsorbing devices as possible (like airbags with timed deflation). Make the slug in such a way that it will crack open in a controlled manner when hitting the comet (most bullets do this). Launch. Hit. Drive

  • The beginnings of life, here they come! (Score:5, Informative)

    by smooth wombat ( 796938 ) on Friday February 03, 2006 @03:49PM (#14637090) Journal
    So if a comet similar to Tempel 1 just happens to fly by a star similar to IRS 46 [slashdot.org], which happens to have a dust ring with acetylene and hydrogen cyanide in it, the combination could give us amino acids, the precursors to adenine.

    Woot! 1/4 of the way to the formation of DNA!

    Run Tempel 1, run!

    • Re:The beginnings of life, here they come! (Score:5, Insightful)

      by The Snowman ( 116231 ) * on Friday February 03, 2006 @03:56PM (#14637149)

      While I don't know much about organic chemistry, you sound like you know what you are talking about, so I'll agree with you. Anyway, this is why we need to keep sending out these probes and learning stuff. Maybe we will reveal clues about the origins of life, and whether there is life out there or not. Hell, we might discover an intelligent life form. And, to paraphrase some wise man who I think was a SciFi author but I don't remember who: we must discover if there is intelligent life in this universe so we can build spaceships, travel to meet them, and obliterate them.

    • <tounge placement=cheek>
      Sure, as long as there's a intelligence to start, guide and complete the design of molecular formulae. I mean, how ELSE does life develop?
      </tounge>
      • hopefully you can put your tongue in your cheek and not your tounge. the combination of all those things at the right time can create amino acids, but what are the chances that nothing will happen? and what are the chances that the other 3/4 of the things needed for the formation of DNA will be created? and what are the chances that they will all come together?
        • Give it enough time the probability is nearly a certaintity.
          • It seems a better answer that "given enough time and opportunities, the results become almost certain". We're talking about timescales of millennia (1,000s of years) to eons (1,000,000,000s of years), and then we're talking about uncountable trillions of atomic and molecular opportunities EACH YEAR in just ONE solar system for chemical action to take place. Time+Atoms+Energy = Molecules (like amino acids and water), and then Time+Molecules+Energy = Chemicals (for example, DNA and liquid water), and then T
            • Wow. Trillions. I'm impressed. How could I have been so foolish as to expect a sound, reasoned argument when the numbers are so big, beyond the capacity of the human mind to comprehend.
              • It's because of these uncountable trillions of atomic and molecular opportunities that mankind produces all the chemicals that it does. Mankind merely speeds up the process of chemistry, producing things like acids in millions of tons by industry. So it's hardly difficult to give credit to these things happening naturally for organic chemicals when trillions of opportunities take place in a solar system each year.

                Think of Nature as being a very patient and diffuse chemist, whereas the Engineer is a ver

    • Re:The beginnings of life, here they come! (Score:5, Interesting)

      by KiloByte ( 825081 ) on Friday February 03, 2006 @05:03PM (#14637645)
      1. Get a pile of anything that consists mostly of C,H,O&N.
      2. Let ultraviolet or similar things affect it.
      3. Watch it spawn amino acids and the rest of important chemicals.
      4. Proceed for a looooong time, while combinations of simple proteins form and get broken down.
      5. After enough time, watch a protein complex have the ability to copy itself.
      6. Have it die, then spawn elsewhere every a million years or so.
      7. Watch one of such complexes survive long enough to have one of its many copies hit by ultraviolet (mutate) to form something more complex.
      8. Have the pre-life grow a cellular wall, turning sparse pools of dirty water turn into small, concentrated tiny blobs of life. Organisms.
      9. With actual cells, everything goes downhill.
      10. Watch someone invent (create) the underpants gnomes.
      11. ...

      Once a structure gets the ability to multiply, it can form new structures. Another example: since creationism and most religions include an urge to preach to non-believers, it _does_ survive. And, it does mutate and evolve into forms such as ID which have a better chance of survival in the hostile environment.

  • What color is the comet? (Score:4, Funny)

    by Quaoar ( 614366 ) on Friday February 03, 2006 @03:52PM (#14637108)
    Cause if it's yellow, then whoever made it didn't use snow...
  • I the commet's water didn't contain life in the first place, mayby we just contaminated it with whatever cleaver microbes hitched a ride on the impactor. That'd be sweet.

    • ...whatever cleaver microbes hitched a ride...

      Yikes, I've never even heard of cleaver microbes. But if they were able to make it into the super sterile room they no doubt kept the impactor in, and managed to survive the trip into space and the subsequent collision at high speed into a comet then we're all in serious trouble.

      Everyone should take this opportunity to lock up their nano-vegetables for safe keeping, perhaps in a Buckyball or a small cage made of Carbon Nano-tubes.

  • FTA:

    The team also found the comet was much weaker structurally than previously believed; the soufflé-like comet is more empty space than rock and ice.

    From the wikipedia article on Deep Impact [wikipedia.org]:

    The Deep Impact mission will help answer fundamental questions about comets, such as:

    • Is the nucleus layered?

    • Are cometary nuclei highly cohesive and tightly-packed, or porous conglomerates? (Checked!)

    • Do any parts of a cometary nucleus contain pristine material that have been untou

    • Do any parts of a cometary nucleus contain pristine material that have been untouched since the creation of the comet during the Solar System's early history?

      It's nice to know that one of those questions just got answered (so it's time to update the wikipedia article :)

      Actually we know the answer to the third question as well: No! Duh...we just rammed a probe into it!

  • Of course, the Heaven's Gate members already knew all of this...

  • Dirty snowball effect. (Score:5, Interesting)

    by AJWM ( 19027 ) on Friday February 03, 2006 @05:25PM (#14637797) Homepage
    The finding suggests the comet's surrounding cloud of gas and dust may largely be fed by underlying ices, rather than by gas streaming off its surface.

    This is hardly surprising. Out in my backyard, there's the remains of a snowman my daughter made a couple of weeks ago. It's black.

    Oh, it was white -- and much bigger -- when she made it, but in rolling up the snow (only a couple inches deep) to make it, the snow picked up a fair bit of sand and dirt. Now, after the outer few inches has melted, the dirt that was in those few inches has settled back to the new surface while the water has melted/evaporated away. The result -- a fairly solid dirt surface.

    Any city dweller in the northeast sees this every spring in the dirty snowbanks beside plowed roads.

    It's hard for gas to stream off a surface that's a thick layer of dust and grit. More likely for it to come from the ices underneath. What would be interesting -- and would require a soft landing on a comet -- is to measure the thickness of the outer dirt "crust" and look at the volume of dirt per unit volume of ice underneath that. That'd let you calculate the approximate thickness of the ice already evaporated from the comet.
    • The standard model of a comet is as a dirty iceball -- like Frosty parked out in your yard. I am thinking more snowy dirtball. The first pictures of Halley's Comet showed that it was quite dark. I have been thinking that a chunk of comet is more like those chunks of pavement that spall off potholes than the slushy snow that the plow truck shovels to the side.

      Yep, I am thinking road pothole leavings -- a conglomerate of silicates, hydrocarbons, with a little bit of ice mixed in. Arthur C Clark has a pl

      • Like the grandparent post said... It's like a snowman that started much larger and has been melting for millions of years. It started as an dirty snowball, but billions of years of slow evaporation have resulted in an outer layer of dirt essentially insulating the water just below the surface so that it doesn't all evaporate in one pass.

        As for the dirt being souffle-like -- what do you expect? There's barely enough gravity to keep the comet together, and almost nothing to force the residual dust to compa

        • But I don't agree with the grandparent post about the dirt coat on a withering snowball. It is just an intuition shy of a hypothesis, but the data points are 1) the very dark pictures of the solid object that makes up a comet, 2) the very dark C-type asteroids, 3), the seeming continuum between comets and C-type asteroids, 4) the carbonaceous chondrite meteorites, 4) the high silicate content of interstellar dust grains from which the Solar System formed.

          Ice may be a more minor constituant of these thing

          • It is just an intuition shy of a hypothesis,

            It starts as an observation. I don't know where you live, but I've also seen the result when snowmen and snow banks melt. It is as he described -- the surface basically distills down to the non-evaporative elements that were in the upper depth. For dirtier snow (e.g. snow tossed off of the road that was also sanded for traction) the distilled dirt insulates the remaining snow and keeps it from melting weeks past when the 'clean' snow is gone.
            Those are act

            • > It starts as an observation.

              But not, I see, an observation of comets. The observation of comets leads to the conclusion that comets have little to no ice. I know you've been told for years that comets are dirty snowballs, and that your worldview depends on the blind acceptance of the priestly authority of most holy scientists, but, yo, dude, this comet is a big rock. So were the other comets. I see a trend here.

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