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Earth Space Science

Earth Ejecta Could Seed Life On Europa 130

Posted by Soulskill
from the i-now-fear-the-europaraptor dept.
KentuckyFC writes "Various astronomers have studied how far rocks can travel through space after being ejected from Earth. Their conclusion is that it's relatively easy for bits of Earth to end up on the Moon or Venus, but very little would get to Mars because it would have to overcome gravity from both the Sun and the Earth. Now, the biggest ever simulation of Earth ejecta confirms this result — with a twist. The simulation shows that Jupiter is a much more likely destination than Mars. So bits of Earth could have ended up on Jovian satellites such as Europa. Astrobiologists estimate that Earth's hardiest organisms can survive up to 30,000 years in space, which means that if conditions are just right, Earth ejecta could seed life there."
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Earth Ejecta Could Seed Life On Europa

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  • However long life may survive in space, when the organisms reach Europa, they get a message saying "DO NOT ATTEMPT TO LAND THERE" and get blasted out of the sky.

    • by eclectus (209883)

      It already reached Europa, thrived, and is attempting to stop anything else from landing. Why else do you think it spoke english?

    • I live in europea but i dont see organisms no where not even sound but they says theres in sky should i be worrie. i herd on the webs that organism has invaded but i dont see them no where wats going on.
  • The latest evidence has fossil life appearing on Earth so soon after the LHB that it is implausible it evolved here.
    • by ginbot462 (626023)

      I'm too tired. I read that as "as evidenced by LRH (L. Ron Hubbard), it is implausible life evolved." And, i agree with that. Course, the counter argument is he was a highly evolved gibbon (no offense towards gibbons).

    • by MBGMorden (803437)

      Without some basis for seeing it arrive elsewhere, it's pretty hard to proclaim any timeframe as "implausible". Until we get good date from other examples there's just no way to get an estimate on the normal time it would take for life to evolve from scratch to know whether it was accelerated or not in our case.

    • by Anonymous Coward

      To save anyone else the bother of googling it to be reminded.

    • by osu-neko (2604)

      The latest evidence has fossil life appearing on Earth so soon after the LHB that it is implausible it evolved here.

      Interesting. That's pretty much the exact opposite of what the scientists discussing the latest evidence said on the interview I heard. Latest evidence has fossil life appearing on Earth so soon after the LHB that it seems implausible that it takes life very long to evolve, given the right conditions. Lacking evidence that it takes life much longer to get going than it did, and further that some more hospitable place for it to evolve existed, and further still that it then managed to get transplanted fro

    • by RockDoctor (15477)

      The latest evidence has fossil life appearing on Earth so soon after the LHB that it is implausible it evolved here.

      Having just downloaded the paper to read over lunch and siesta, I'm wondering what makes you find the idea of life evolving on Earth so implausible that you're willing to accept the severe difficulties of panspermia, and the unresolved difficulty of having to have somewhere that life did originally evolve at. Not forgetting of course that there is only time for a limited number of panspermia c

      • by symbolset (646467) *

        I did download and read the paper as you suggested. They seem to be quite thorough. It's a good paper. As my opinion mattered I don't disagree with it, and it does lay out some specific conditions likely to have occurred where an impactor might have landed earthly life in still-viable condition on Mars and other planets. I suppose I'm going to have to read the referenced paper on the 30ka. I'm not sold on the idea that the "nonviability" of the organism is the end of the story here. Even a thoroughly

        • by symbolset (646467) *
          That was supposed to read "as if my opinion mattered" - as in, "I am not a rocket scientist."
        • by RockDoctor (15477)
          Some points as they occur to me - then I've got EoWR to write.
          • 1a - consider the Jack Hills and Acasta detrital zircons with the oxygen isotope compositions appropriate to an active hydrological cycle ... and which seemingly date back as far as 4300Ma, if not older. The work is replicated, from multiple areas. The belief that the planet had a thoroughly molten surface any significant time after the Moon-forming Giant Impact ... is in serious trouble form material evidence. It always had difficulty from an e
          • by symbolset (646467) *

            First, you might want to consult with your physician about the dosage of your meds.

            Second, nobody's reading this old thread except you and me, so we may as well have a private discussion.

            2a,b,c - ALL panspermia models have the problem that life has to originate somewhere, either in space or on a planet. Then it has to get here without being destroyed through space. Then it has to proliferate in the extremely different environment on a planet's surface. That is at least one major environmental change (space->planet) which is going to be a bottleneck, along with a (probably) low probability step (non-life->life). That is a pair of low probability events happening pretty independently, so you multiply the probabilities together and get an even lower probability.

            No. There are many panspermia models. I only gave a sample. This is slashdot, not an encyclopedia. Your problem is with the word "somewhere." If you replace that word with "Somewhen" and admit that we're 12 billion years in, the rest is easy.

            4)I didn't say the projectiles came from Ceres. Naturally at that point As

            • by RockDoctor (15477)

              First, you might want to consult with your physician about the dosage of your meds.

              What the fuck prompted that?

              You made a comment about panspermia concepts ; I replied ; we're exchanging ideas civilly, then you come out with the typewritten equivalent of throwing a beer in my face. If anyone should be checking meds, it isn't me (BTW the doses are one set of tabs of a broad-spectrum antibiotic, one set of industrial grade antihistamines, and malaria prophylaxis ; and I competed the first two courses yester

              • by symbolset (646467) *
                Sorry - I get a little cranky sometimes.
                • by RockDoctor (15477)
                  (Slashdot seemed unhappy with it's existence earlier, but I saved my reply and will try again.)

                  Apology accepted. Now, where were we?

                  Summary of my position : Panspermia is not impossible, in the strict sense, but unnecessarily complex given that you've got to have an origin of life somewhere, and only a limited number of cycles available in a universe of finite age. So, if you want a Copernican universe ("we're nowhere unusual"), you'll still have to have lots of separate panspermia origins to put us in an

  • Well this is interesting. The fact that it is easier for our ejecta to get to a moon of Jupiter than Mars when Mars is much further away is counterintuitive and cool. But, this means that even if we find life on Europa, unless that life's basic biochemistry is radically different from that on Earth, we won't be getting any useful data about how difficult it is for life to start. The Drake Equation http://en.wikipedia.org/wiki/Drake_equation [wikipedia.org] and variants thereof try to get an estimate for how common intelli

    • by JoshuaZ (1134087)
      Ugh, should pay more attention to preview. Last part got cut off from bad URL link. Mean to say:

      Well this is interesting. The fact that it is easier for our ejecta to get to a moon of Jupiter than Mars when Mars is much further away is counterintuitive and cool. But, this means that even if we find life on Europa, unless that life's basic biochemistry is radically different from that on Earth, we won't be getting any useful data about how difficult it is for life to start. The Drake Equation http://en.wik [wikipedia.org]

      • Well this is interesting. The fact that it is easier for our ejecta to get to a moon of Jupiter than Mars when Mars is much further away is counterintuitive and cool.

        I can't say though I find this really surprising. I suspect the average Joe (layman, astronomically-speaking) tends to think of the planets in a linear precession, each further from the Sun than the previous one; we grew up in classrooms with posters depicting them like that ; the truth being, of course, the planets all orbit at individual rates, (sometimes I forget too) so at times, the Earth could be in an inferior conjunction with Jupiter, but Mars is all the way over on the opposite side of the Solar S

        • by JoshuaZ (1134087)
          Hindsight here is wrong. That's a typo. My point was that Mars is generally closer than Jupiter but that it is easier to get ejecta to Mars than Earth. That's what is counterintuitive. Even when Mars and Earth are opposite each other they are only about 15-20 light minutes apart. When Earth and Jupiter are near each other they are still farther away than that.
          • by Anonymous Coward
            I eagerly await version 2.0 of this post.
    • The fact that it is easier for our ejecta to get to a moon of Jupiter than Mars when Mars is much further away is counterintuitive and cool.

      Umm, Mars is actually much CLOSER than Europa.

      • by JoshuaZ (1134087)
        Er yes, that's why it is counterintuitive that it is easier to get Jupiter. Wow. I really need to work on the whole preview thing a lot more.
        • Er yes, that's why it is counterintuitive that it is easier to get Jupiter. Wow. I really need to work on the whole preview thing a lot more.

          What's really sad is that you realized you'd made a mistake on your original post, reposted it with the correction, and left the "mars is farther away" thing in the revised one too. ;)

          That aside, it is pretty cool that it's easier to reach Jupiter's satellites than Mars. Especially given that the ejecta can reach Venus, which requires only a tiny bit less deltaV to r

        • by cusco (717999)
          Don't worry, it's Monday.
  • by Anonymous Coward

    could anybody come up with a dirtier title for a story?

    -- posted as AC due to moderator violence [slashdot.org].

  • If it's easier for rocks to come sunward, then does that mean there's a chance that life-bearing rocks from Europa could have seeded the Earth.
    • by BetaDays (2355424)
      I knew I wasn't from around here.
    • by MBGMorden (803437)

      Possible - but realistically you're putting the cart before the horse there. There's no evidence as of yet that there even is any life on Europa - or ever has been. It's a possibility sure, but until we at least have evidence to support life in the past there then any speculation on it seeding a planet with abundant known life isn't very useful.

      Or, put more simply: you should always look for evidence that something DID happen than to come up with some scenario that has no current evidence against it and a

      • by petes_PoV (912422)

        you should always look for evidence that something DID happen

        True, but since this entire topic (that Earth could have seeded Europa) is conjecture, a little more doesn't hurt. And since we know there's life on Earth wondering where it came from is more fruitful.

    • I'm no expert on such things, so feel free to ignore these musings.

      I've often wondered if life really originated on another planet in our solar system, then came to Earth, why would it never have developed into something like we have here.

      If it happened elsewhere first, then would they not have been more advanced, or did they never get past a certain phase? Or would the life form there be so different that we'd never have anything common enough to be able to identify the other as a life form.

      Obviously, if p

      • by tophermeyer (1573841) on Monday August 22, 2011 @10:39AM (#37167958)

        I think an unspoken assumption you are making is that the evolution of life "advances" toward intelligence linearly at a common rate. This isn't really accurate. Advanced life does not necessarily mean intelligent life.

        Life may well exist on Europa, and may well have existed for just as long as life on earth. We can look for examples in the communities surviving around deep ocean thermal vents (which are likely the best analog we have for the environment in Europa's oceans). Those environments are teaming with life in a fairly small area. That life isn't intelligent, and may never face the evolutionary pressures that will lead to the development of intelligence, but is very very highly adapted to an extremely harsh environment. That level of evolution can be considered every bit as "advanced" as our intelligence.

        • by RockDoctor (15477)

          I think an unspoken assumption you are making is that the evolution of life "advances" toward intelligence linearly at a common rate. This isn't really accurate. Advanced life does not necessarily mean intelligent life.

          Simon Conway-Morris would disagree with you on that. I don't necessarily agree with him, but he's a sufficiently respected figure in evolutionary theory and palaeontology (and arguing a contrarian point of view) that you've at least got to read his opinions.

          We can look for examples in the co

      • by sjames (1099)

        If life began on Europa and seeded Earth, what happened to stop further development on Europa?

        A less conducive environment?

      • by Thing 1 (178996)

        If life began on Europa and seeded Earth, what happened to stop further development on Europa?

        The sun got cooler?

        • Well, that's something I had thought about. But wouldn't the cooling of the sun happen slow enough for any intelligent race to do something about it? Like migrate inwards, to Mars or, ultimately Earth?

          There's a lot of assumptions here, as I said I'm not expert. I'm only speaking for a very sketchy background of high-school physics, general interest, and a lot of sci-fi books :)

          If we are to consider that some form of life existed on Europa, and there were conditions good enough for them to develop into somet

          • by osu-neko (2604)
            Hate to throw a wet blanket on this whole thing, but... the Sun has not gotten cooler. Hydrogen burning stars (and the Sun is still in that stage) get hotter as they get older, burning their remaining hydrogen at an ever increasing rate as they age. The Sun gets about 10% brighter every billion years. What you'd want to do to stay in the habitable zone is migrate outwards.
            • How long before Mars becomes warm enough to be more habitable?

              • by Coren22 (1625475)

                Never. You know life did come from other parts of the solar system. First we tried Mars, but we couldn't seem to keep an atmosphere, then we tried Venus and cooked the planet, then we moved here and have been happy ever since. :)

    • Being smaller, Mars stabilized geologically before Earth and life evolved there first. Then it probably infected Earth.
  • it is my opinion that the theory of comets seeding life on earth, or earth seeding life on europa or mars or elsewhere is completely besides the point:

    the seeds of life are simply everywhere, inside and outside the solar system, and life is simply always lying dormant, everywhere in the galaxy, as bits of flotsam and jetsam of space debris, ready to seed something somewhere, at any time, in the distant future, and the distant past

    this whole argument of where life came from is moot. the potential is simply always there, everywhere, ready to seed

    • by biodata (1981610)
      Fred would have agreed with you: http://en.wikipedia.org/wiki/Fred_Hoyle [wikipedia.org] See his great work Evolution from Space
      • thank you, that's awesome, because like fred i believe the big bang theory is a load of bunk as well

        the universe is infinite in space AND time. the expansion and contraction we see on the "edge" of the universe is a local phenomenon. it's like being on the crest or trough of a wave in the middle of the ocean: the expansion and contraction you see is only local, in an infinite expanse of contractions and expansions

        that's just my opinion, but since we first started looking skyward (geocentric solar system deb

        • by Chris Burke (6130)

          that's just my opinion, but since we first started looking skyward (geocentric solar system debunked, etc.) we always seem to fall for the prejudice we are at the center of things happening. the big bang theory is simple an extension of this prejudice. the march of astronomical progress has always shown we aren't anywhere special, or any TIME special

          Except modern cosmological theory, including and especially the Big Bang, are based on the assumption that we aren't at "the center", that we aren't at a special time or place.

          Sounds like you just have misunderstood the theory and from that basis believe it to be bunk.

    • I think you hit the nail on the head.
    • by mangu (126918) on Monday August 22, 2011 @09:57AM (#37167562)

      the seeds of life are simply everywhere, inside and outside the solar system, and life is simply always lying dormant, everywhere in the galaxy

      I'd say the elements of life are everywhere, but not the seeds. Having the material but not the proper information is not enough. Life is composed by amino acids, but those are merely the bricks used to make proteins. One must have a suitable floor plan to build a house.

      What makes conditions on early earth so special is not the existence of organic chemistry, but the special circumstances, so far not known to us, that brought the formation of complex self-reproducing chains of amino acids.

      • agreed 100%. except what we are talking about is indeed accurately described as seeds

        we all understand we aren't talking about a literal plant based seed

        we are talking about the most basic molecular units that have the potential to replicate in the right environment. seeds

        i mean if you still find use of the word seed as confusing, i would counter that the use of the word element in this context is equally confusing, as we aren't talking about just literal carbon and nitrogen, but how those elements are arra

        • by mangu (126918)

          The papers mentioned in TFA mention the probability of a rock ejected from Earth reaching Europa. I didn't see in the abstract anything about the probability of survival of a viable spore.

          We must take into account that all life is dependent of an ecological niche. For earth to seed life on another planet or vice versa one would need a spore that can survive the extreme conditions of vacuum, temperature variations, and radiation found in space. Then those spores should find an environment where they landed t

          • we're not talking about organisms. we're talking about basic molecular units of replication

            still, the chance of such units getting ejected from one place of life, and seeding another place of potential life, is, obviously, vanishingly small

            but over vast stretches of space and vast stretches of time, it goes from tiny possibility to probability

          • DNA forms pyrimidine dimers [wikipedia.org] when exposed to energetic photons of UV and higher. The way life keeps living despite the mild exposure to gamma radiation on Earth is through active repair. In space, not only will organisms not have any active metabolism to accomplish repair, cosmic radiation is constant, and the longer a specimen is drifting through space, the more likely it is to be exposed to a heavy burst of X-rays or gamma rays from a solar flare. If a human were out prancing around on the moon when a s
      • by HiThere (15173)

        You are making some assumptions that may not be true. Amino acids work as elements of life at temperatures around the melting point/boiling point of water under what seem to be normal planetary atmospheres. It's not clear that they would work on, e.g., Titan. You'd probably want something a bit more active. Maybe life isn't possible there, but I don't think that's the way to bet. (It could, of course, be more improbable, but then we don't know just how likely life was to arise on earth. It seems, in r

      • by Thing 1 (178996)

        I'd say the elements of life are everywhere [...]

        Yeah, ever since the supernova...

        What makes conditions on early earth so special is not the existence of organic chemistry, but the special circumstances, so far not known to us, that brought the formation of complex self-reproducing chains of amino acids.

        Without the moon, nothing would have combined.

  • Long live the Cockroach!
    • I think you'll find it's the Waterbear [wikipedia.org]

      • They prefer the term Aquaursus. Bears' real name was originally in German which they spoke ... later they would go on to form ancient Slavic languages as well and star in Bugs Bunny cartoons. The Ursidae Cabal knew that knowing their real name with give power over them including being able to merge with one to become a werebear (you might heard of one .. ColBEAR). The story of owlbears is too gross, but Aquaursus were ancient protobears that evolved into a highly intelligent republic of entities - retainin

        • by ginbot462 (626023)

          "In May 2011, studies involving tardigrades[Aquaursus] were included on STS-134, the final flight of Space Shuttle Endeavour."

          Should have read that earlier, these are advanced scouts for the Space Bear. I mean ... obviously.

        • by Yamioni (2424602)
          Your ideas are intriguing to me, and I wish to subscribe to your newsletter.
    • All glory to the waterbear! [wikipedia.org]

      • by ginbot462 (626023)

        You must know of their http://science.slashdot.org/comments.pl?sid=2391554&cid=37167712 [slashdot.org]">plans too and are trying to get on their good side. Like the Remora, a few lucky souls will be allowed to serve them in the Cave of Hops and Honey. It will involve a lot of temporal maintenance and cleanup; on the plus side, the Hilter Time Traveling Exemption (http://tvtropes.org/pmwiki/pmwiki.php/Main/ptitlekz83hawz) will be lifted and whole cottage industry will be setup to assassinate him over and over again

        • by ildon (413912)

          Ha, that's what I get for getting distracted and reading the waterbear article before clicking submit.

  • Why wait for nature and chance? Launch some seed rockets.
  • by advocate_one (662832) on Monday August 22, 2011 @09:09AM (#37167088)
    Surely any event that could eject material from earth with sufficient energy to escape Earth's gravity well would tend to melt the ejecta at the same time, so the bacteria would have to be seriously hardy...
    • by mbone (558574) on Monday August 22, 2011 @11:53AM (#37168612)

      Surely any event that could eject material from earth with sufficient energy to escape Earth's gravity well would tend to melt the ejecta at the same time,

      No. Some, but not all. Here is a mechanism - impacting object hits, penetrates, and is stopped and imparts spherical shock wave into the Earth (or other planet) some depth inside the planet. (In simple terms, it explodes inside the crust of the Earth.) Some part of that shock wave is propagating near vertically up, away from the planet (including, maybe, parts that reflect from internal structure). These shocks lift material up out of what becomes the crater. For a 2 km crater (such as the Great Meteor Crater in Arizona), these shocks turn the layers in the near surface material upside down, just lifting and flipping them over in much the same way you would flip over a pancake, moves a mass of material maybe 1 km, without vaporizing any except for a small fraction near where the impactor stops. For a 100+ km crater, that some process pushes the some of the surface layers off the planet entirely (and also causes long rays, such as are found on the Moon). While some of the ejected material is vaporized, most isn't, and some is treated quite gently (for a massive explosion), gently enough that biological spores and the like could survive the experience.

      • IANAP (I am not a physicist) rather only a lowly geneticist. However, one question for someone that sounds like he understands the physics involved here:

        I'll accept your assertion at face value that a rock containing spores could be ejected in such a way that some hardy spores could survive.

        Now tell me this: This rock has to have the right amount of energy to reach Europa. Does it get blasted to bits upon impact and incinerate our little friends? The seeding hypothesis purported here sounds like the
    • by utkonos (2104836)
      I think you may be quite surprised at how many extremophile archaea there are, and what kind of conditions they can survive in. Alternatively, humans have been sending rocket-assisted ejecta into space for years and years.
  • The problem with Europa is that the interesting bits we want to get at are under (at least) 20 kilometers of ice. Whoever figures out how to breach that without destroying the environment beneath is going to be a winner in the big NASA lottery, and enable a lot of exciting exploration. Callisto probably has a similar subsurface ocean, for instance -

    • by ArcherB (796902) on Monday August 22, 2011 @10:47AM (#37168028) Journal

      The problem with Europa is that the interesting bits we want to get at are under (at least) 20 kilometers of ice. Whoever figures out how to breach that without destroying the environment beneath is going to be a winner in the big NASA lottery, and enable a lot of exciting exploration. Callisto probably has a similar subsurface ocean, for instance -

      If I understand what I've read about Europa, we may not need to get through the ice at all. Due to tidal tugging, Europa is full of cracks. When those cracks form, it is believed that liquid water cycles to the surface and freezes again. It's Europa's version of plate tectonics. We should be able to get an excellent idea of what is below the surface by taking a sample of the surface ice on the surface near these cracks or even within the cracks themselves. As a bonus, whatever we find will be pre-frozen. Kinda like the frozen veggie aisle at your local grocer.

      Why we have not sent a probe to land on Europa by now is beyond me.

      • by Thing 1 (178996)

        Why we have not sent a probe to land on Europa by now is beyond me.

        But, apparently, not beyond Arthur C. Clarke.

  • Lets fill a probe with biological stuff we think might work there and seed the thing ourselves!
    • by Baloroth (2370816)

      Lets fill a probe with biological stuff we think might work there and seed the thing ourselves!

      There is definitely a joke in there somewhere...

  • I told my wife I wanted to use my ejecta to seed life in^H^Hon Uranus, but she said no way.

  • This is a classic scifi scenario, just entirely reversed.
    Let's send our "alien" meteorites to crash on other planets and spread our biological monsters!
    Now let's hope European(*) Bruce Willis doesn't try to nuke it before it arrives.

    (*) I am obviously talking of the on-topic Europa, but the idea of Bruce Willis with stereotypical French attire kind of makes me giggle. You know the beret and stripped shirt and baguette thing (no offence intended to real Frenchmen. Salut!)

    • by Sockatume (732728)

      I think there was something like that in Hudson Hawk. The Bruce Willis bit, I mean, not panspermia.

  • You've heard of panspermiation, but lets call it what it is, a massive organic molecule cross pollination, with everything coming from one's own solar system. I have a real hard time accepting panspermiation from interstellar space. And while it might happen, the odds of it are is virtually zero. I'd assume those events to be from supernovas which would likely destroy any organic bonds as the material gets distributed throughout the universe on the shockwave of the supernova. Then it has to survive stellar

    • No need of a supernova, and no one has ever suggested that as a mechanism. There is the possibility of directed panspermia if you're into sci-fi, or just rocks flying free from their solar systems.
      http://www.centauri-dreams.org/?p=188 [centauri-dreams.org]

      All you need is a lot of material, to have decent odds.

      One meteor speed listed there is 300km/s - at that speed, it would take 4000 years to get to Alpha Centauri. If life can survive reasonably well for 30,000 years, that gets to quite a few stars nearby. You just need a lo

      • by scorp1us (235526)

        Oh, I completely, agree, that reaching a star system is possible, possibly even probable, given a direct course. However to contribute it must survive the journey and reach the right destination. Given that suns are the biggest attractor, and heavy Jupiters are next most attractors, these guys will suck up the majority of material and destroy it through temperature. Even after arriving on an planet of suitable composition, temperature and chemistry, it still has to wait around and last long enough to influ

  • Misleading summary (Score:4, Informative)

    by mbone (558574) on Monday August 22, 2011 @10:19AM (#37167766)

    Mars rocks have been found on Earth, and it has been a standard assumption in planetary science for some time now that Earth rocks have also been going to Mars by the same mechanism. You wouldn't know it from the summary, but the actual paper [arxiv.org] also predicts a significant rate of mass exchange Earth -> Mars -

    Gladman et al. (2005) estimated the collision rate with Mars to be about 2 orders of magnitude lower that found on the basis of our simulations. However, as also noted in their paper, our results for Mars are within the known typical errors of such probability estimations. ... Both results, definite collisions with Mars and Jupiter, are of astrobiological significance,...

  • by jonadab (583620)
    Wake me up if it ever amounts to anything you don't need a microscope to see.
  • by JoeRobe (207552) on Monday August 22, 2011 @10:54AM (#37168124) Homepage

    I've previously heard this quote of organisms surviving for up to 30,000 years in space, but does anyone happen to have a real scientific reference for it? I'm really wondering what can survive that long with no fuel at all, unless the argument is that the whatever rock the organism sits on during its travels through space happens to have some nutrients on it. Even the waterbear still needs some energy after it goes into a cryptobiotic state, right?

    • by osu-neko (2604)
      Life doesn't need nutrients if the life-process can be shut down entirely, then restarted when conditions are favorable, and this is the case for many microorganisms. The waterbear may still need some energy, but it's much larger than what we're talking about here, also much more complex, and way more fragile/less hardy than many microorganisms.
      • by JoeRobe (207552)

        Ok then in that case, is there a reference for single-celled organisms that can completely turn themselves off at ~0 K temperatures and in a vacuum, then turn themselves back on? Now I'm really curious about this. I'm also thinking that after 30,000 years, the organism will have an enormous amount of UV, X-ray, and solar wind exposure that would break down most chemical bonds. That kind of exposure may not be immediately deadly to a larger organism that has a skin or outer shell, but for a single cell, t

  • by neostorm (462848) on Monday August 22, 2011 @10:59AM (#37168162)

    Send a note with it, will you? I hate the thought of bringing up a whole planet of lifeforms just so they can bang their heads and kill one another over the confusion of where they came from and why. ;)

    • by osu-neko (2604)

      Send a note with it, will you? I hate the thought of bringing up a whole planet of lifeforms just so they can bang their heads and kill one another over the confusion of where they came from and why. ;)

      Alas, all evidence suggests that lifeforms will bang their heads and kill one another in any case. What they may or may not be confused about only provides convenient excuses for doing and/or justifying what they wanted to do anyway...

  • In the 3+ billion years life has been on Earth I would guess that life from Earth could have gotten to Mars even if it has lower probability than other locales.

    So if we find life on Mars, or some moon of a gas giant, do we assume it got their from Earth or not?

    • by osu-neko (2604)

      In the 3+ billion years life has been on Earth I would guess that life from Earth could have gotten to Mars even if it has lower probability than other locales.

      So if we find life on Mars, or some moon of a gas giant, do we assume it got their from Earth or not?

      Depending on when the migration took place, that might be a trivially easy question to answer. A strange life based on chemical processes entirely unrelated to anything on Earth today may leave us questioning, but RNA or DNA-based microorganisms with identifiable gene-sequences from strains that evolved on Earth with a clear fossil record would leave no question at all. So the answer to you question is, it depends on what we find...

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