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Earth Life Possibly Could Reach Titan

Posted by Zonk on Fri Mar 17, 2006 05:43 PM
from the bacteria-with-heavy-coats-now-thriving-there dept.
Space
dylanduck writes "New simulations show that big asteroid impacts on Earth could have sent about 600 million boulders flying into space. About 100 have reached Jupiter's moon Europa - but they landed at 24 miles/sec. 'This must be rather frustrating if you're a bacterium that survived launch from Earth,' says a researcher. But 30 boulders from each impact reach Titan - and they land gently." From the article: "'I thought the Titan result was really surprising - how many would get there and how slowly they'd land,' Treiman told New Scientist. 'The thing I don't know about is if there are any bugs on Earth that would be happy living on Titan.' Titan's surface temperature is a very cold -179C and its chemistry is very different from Earth's."
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  • Lawyers.

    They can survive anywhere.

  • Airborne bacteria? (Score:5, Interesting)

    by Bahumat (213955) on Friday March 17 2006, @05:47PM (#14945523) Homepage Journal
    Leads to the interesting possibility of xenophilic bacteria and algae impacting Jupiter and having their entry slowed greatly by the thick atmosphere. The deeper it goes, the warmer it gets, and there are bands in Jupiter's atmosphere that are comparable to Earth's atmosphere, past and present.

    Might be interesting to one day discover man was far from the first Earth-borne species to begin colonizing other planets in the solar system.
    • ...why shouldn't bacteria from Earth be able to grow on Titan? Microbes are amazingly hardy organisms, they can thrive as chemotrophs at the bottom of the ocean near volcanic vents or in other incredibly hot temperatures (one such microbe has an enzyme that lets biologists amplify DNA for legal and research purposes). If they can survive the extremes of air, ocean depth, and heat, why not those of cold and darkness?

      • Mir was a good example... (Score:5, Interesting)

        by jd (1658) <imipakNO@SPAMyahoo.com> on Friday March 17 2006, @08:16PM (#14946150) Homepage Journal
        And NASA carried out a related experiment not too long ago, plastering microbes on a surface they then exposed to the hard vaccuum & hard radiation of space. The microbes stopped growing in space, but went into a suspended state. When returned to Earth, they revived and did not appear to have been harmed any by the experience.


        (Given that gigantic, green tentacled monsters haven't been stalking NASA bases recently, we can also assume that not only were they not killed off, they did not suffer significant mutation from the radiation. Actually, the study indicated that no obvious mutations had occured of any kind, implying that the DNA was highly resiliant to the effects of ionizing radiation.)


        On the basis of Mir and the NASA experiment, it can reasonably be concluded that microbes can survive interplanetary travel, more-or-less intact, at least within the solar system. Deep space is far, far nastier and the present experiments don't show that interstellar microbial travel is possible... but it doesn't rule it out, either.


        We believe that microbes can remain in a suspended state for tens of thousands of year (or perhaps millions), on the basis of studies of microbes discovered in ice core samples. It's not easy to rule out contamination, but the experiments seem repeatable. It is possible to imagine that microbes may be present in some geodes. They would certainly be present inside rocks that have fissures caused by flowing water or ice cracking.


        Once you're talking of microbes on the inside of rock, then impact velocities would be much less important. The rock would absorb much of the impact, and the shattering of the rock would be a very useful way for the microbes to be released. In the case of interstellar travel, it would also provide better shielding. Ideally, you'd want rock from the Peak District in the UK - some places have a nice mix of galena (lead ore), calcite and blue feldspar. I could easily imagine a meteorite with such a mix containing microbes in amongst the calcite, and lead casing would improve the odds of surviving the millions - if not billions - of years needed to travel between systems.


        (This is not to say this has happened, and I'm sure I'm going to get my wrist slapped by a geologist who will point out all the flaws in my reasoning. However, if in the year 3000 we finally reach Alpha Centauri and find a planetoid with bird flu on it, they'd better damn well name the planetoid after me.)

        • Re:Mir was a good example... (Score:5, Informative)

          by Decaff (42676) on Friday March 17 2006, @11:58PM (#14946788)
          Once you're talking of microbes on the inside of rock, then impact velocities would be much less important. The rock would absorb much of the impact

          Actually, microbes are so tough that there is little need to absorb impact stresses. Some experiments have involved bacteria put inside a rifle bullet and fired at rock (to see if they could survive the decelerations of a meteor impact). The bacteria survived and could reproduce.

          This is why there is little need, as this article suggests, to have the rocks containing bacteria travelling slowly.
        • Totally... I've even seen a clip where scientists have exposed some bacterium to radiation, so to scramble their DNA... Some bacteria can survive, actually repair DNA that was very signifigantly damaged, and then go on about their normal lifecycle. The little bastards are tough!
        • An interesting post. I am not familiar with the tests you refer to but a few things strike me as odd.

          implying that the DNA was highly resilient to the effects of ionizing radiation.

          Isn't one of the points of evolution (and I'm way out of my field here) that DNA is affected by radiation and that is, at least, one of the reasons why species change?
          Just because a small test is conducted and no changes were observed does not imply that DNA is "resilient" at all, right? It only shows that under the con
      • Don't forget that the microbes that live in extreme conditions got there by gradual adaptation. There were once a bunch of microorganisms that could survive in a zone 100 yards to 500 yards from a volcanic vent. Some of those were a little hardier, so they could survive 90 yards from the vent, and so on. But move some of those to a tidepool and they will almost certainly die. For Earth bacteria to live on Titan, they must have lived somewhere with conditions at least a little like Titan, close enough th

    • Re:Airborne bacteria? (Score:5, Informative)

      by isomeme (177414) <cberry@cine.net> on Friday March 17 2006, @07:45PM (#14946043) Homepage Journal
      there are bands in Jupiter's atmosphere that are comparable to Earth's atmosphere, past and present.

      There is certainly a broad layer where the pressure and temperature are roughly Earthlike. However, there is nowhere in Jupiter's atmosphere where the composition is more than vaguely similar to Earth's primal (prebiotic) atmosphere, and nowhere similar to Earth's current atmosphere at all. There is effectively no free oxygen in Jupiter's atmosphere, and only tiny traces of anything other than hydrogen and helium. Most of the traces are simple alkanes and water.

        • Every time I see discussions over whether life could exist on other planets, it always comes up about how much oxygen and water they have. But couldn't life evolve to, say, breathe helium and drink alkaline, for instance?

          No, because helium is a noble gas, and as such chemically inert. The reason oxygen is so usefull is that it is very highly reactive; while it is certainly possible for an organism to inhale helium and not be harmed by it - indeed, even a human can survive that - it won't do it any good

        • Re:Yet another stupid question: (Score:4, Informative)

          by cagle_.25 (715952) on Saturday March 18 2006, @04:26PM (#14949293) Journal
          Generally speaking, you need to move electrons around in order for chemical processes to take place inside a cell. That requires oxidizers and reducers; oxygen is one such, with nice properties that make it suitable for sustaining life:

          • When reduced in the presence of acid (H+ ions), it forms water.
          • It has a relatively strong oxidizing potential (more energy than, say, copper ions or nitrogen), but not so much that it rips molecules apart at room temperature (like fluorine).
          • The fact that O2 is gaseous seems to improve its availability, but I haven't run numbers on that one.

          Oxygen is the simplest substance around that has those characteristics.

          But couldn't life evolve to, say, breathe helium and drink alkaline, for instance?

          Definitely no on the first one. Helium has no chemical properties whatsoever. Hydrogen isn't a good candidate either, since H2 is a reducer rather than an oxidizer. I would imagine that a cell that relied on an outside reducer would need to have free oxidizers sitting around inside itself. It would probably rip itself apart.

          Drinking alkaline is more reasonable, depending on the concentration.

          I don't know if there's a rule that says, "Anything in the universe that's alive has to breathe (carbon dioxide|oxygen), drink water, be carbon-based, etc."

          The "carbon requirement" is simply this: only carbon can form large, stable, complex molecules. Sulfur and nitrogen can form polymers, but not complex ones. Silicon can form large complex molecules, but they tend to fall apart because of the availability of d-orbitals.

        • Re:Airborne bacteria? (Score:4, Insightful)

          by linguizic (806996) on Friday March 17 2006, @08:22PM (#14946166)
          Wouldn't it be something if everyone stopped dodging the most likely possibillity that life started on this planet?
          • First off, I tend to agree with you and I think life did start here, but...

            Given how hard it is for life to start on a planet, how can you say this is the most likely possibility?
            Maybe it is (talking about the odds) more likely that we evolved from some bacteria that somehow found it's way here...

            • Re:Airborne bacteria? (Score:5, Insightful)

              by linguizic (806996) on Friday March 17 2006, @09:59PM (#14946439)
              Panspermia is just a dodge. For some reason people can't believe that here on earth, where life as we know it has done better by far than anyother place that we know of, could possibly have been where life originated. The probabillity of life evolving somewhere else and then being magically whisped away to earth is even MORE improbable than life originating here. Just because something that we know has happened is improbable doesn't mean we have to completely throw all of the most probable scenarios for it to happen out the window.

              • I agree that panspermia smacks of argument from incredulity - "We can't think of a mechanism for life to start on Earth, so we'll say it started somewhere else and hitched a ride on a meteor to get here." Not really much different from "God did it," or "The Flying Spaghetti Monster did it." It doesn't propose an answer for how the life that came from somewhere else started. Until we have a better idea of how widespread life is in the universe, and how similar any of it is to us, we can't say for sure that t

  • Or rather more likely a COLONY of bacteria can have a few members survive the trip, then I'd say it's highly likely that they are mutating fast enough to adapt to local conditions. The bolders would have been radiating heat the entire way out, so temperature wouldn't bother them. They'd land softly enough. And from there on out, it's just survival of the fittest.

  • Panspermia [panspermia.org], but with Earth as the originator. Sounds like the old chicken and egg to me.

  • Water Bears (Score:4, Interesting)

    by 7Ghent (115876) on Friday March 17 2006, @05:56PM (#14945591) Homepage
    Tartigrades, otherwise known as Water Bears [wikipedia.org] might survive such a journey. They're the cutest microscopic animals ever!

  • The Bug Speaks. (Score:5, Funny)

    by Anonymous Coward on Friday March 17 2006, @05:56PM (#14945594)
    'This must be rather frustrating if you're a bacterium that survived launch from Earth'

    On behalf of the League of Sentient One-Celled Organisms, I would like to assure you that it is nowhere near as frustrating as your high-handed, primitive, and anthropomorphic notions of bacterium emotion.

    Actually in many of our cultures (and I use that term advisedly), being hurtled through a vacuum and smashing into a rock is considered to be a transcendent spiritual experience, and required as an initiation rite into our shamanic traditions.

    Blow that into your Kleenex.

  • Obvious (Score:4, Funny)

    by eclectro (227083) on Friday March 17 2006, @05:58PM (#14945607)

    At -179C, the bacteria are gonna need parkas.

  • Was Europa Always Airless? (Score:3, Interesting)

    by Ranger (1783) on Friday March 17 2006, @06:09PM (#14945656) Homepage
    It looks like Earth's pecker tracks could be all over the solar system. What if Europa had an atmosphere early in it's life? Was it always relatively airless? So even if we discover life elsewhere in the solar system, there's a good chance it'll resemble Earth's. Even if Europa was airless what about this scenario? Big Earth rock hits Europa, vaporizes millions of tons of ice and creates a temporary atmosphere. Then a second rock hits Europa in this brief interlude. It could have survived. Unlikely, but possible.
    • What if Europa had an atmosphere early in it's life?

      Sounds reasonable to me. Earth life at the time may have been better suited to Jovian environments than it is now.

    • What if Europa had an atmosphere early in it's life? Was it always relatively airless?

      It's very unlikely that Europa ever had more than a trace-atmosphere at any time. You need a certain amount of mass to generate enough gravity to hold one, although the colder it is, the less you need. I don't have the physics to calulate if Europa's mass is enough, but if it ever did have one, it probably still would.

  • Mars probably had live at some point, either transmitted to Earth via ejecta or received from Earth via ejecta. In fact, it might have gone back and forth over the last few billion years.
    • In fact, it might have gone back and forth over the last few billion years.

      Yikes, that's one helluva commute.

      Maybe that explains why so many modern day humans don't seem to mind driving 2 hours each way to work every day. It's in our genes!

  • Well... (Score:3, Funny)

    by AWhiteFlame (928642) on Friday March 17 2006, @06:40PM (#14945794) Homepage
    Well, as long as they had an intel processor with them, they've got plenty of heat to survive.

  • Could be problematic if we ever got there (Score:3, Interesting)

    by GroeFaZ (850443) on Friday March 17 2006, @06:41PM (#14945796)
    I mean, if we ever got there and searched for native life forms, these findings would just add another factor of uncertainty. Say we send up robots or even taikonauts (probably won't be astronauts any way), and they really do find DNA/RNA-based life (except lawyers, as someone else suggested). How would one tell a archaebacterium which hitch-hiked the vessel from an archaebacterium that hitch-hiked an asteroid boulder from a bacterium that has been created there?

  • Neat idea...wish it were more probable. (Score:4, Interesting)

    by posterlogo (943853) on Friday March 17 2006, @07:17PM (#14945960)
    I hadn't heard before this article about hard evidence that Earth debris could reach other planetary bodies or moons -- it's a really fascinating idea. I would first want to know, however, how many impacts correspond to relatively recent timeframes, and how many were predicted to have occured prior to life evolving on Earth. Also, one would think there would be evidence on our own moon of Earth-based debris (post-formation of the Moon of course, since that is thought to be one large chunk of Earth debris).

    As far as life as we know it, there is no evidence that microorganisms could grow at -179C. There is some evidence that hardy spores can survive in extreme conditions (even naked space as is the case for some mold spores that briefly enter the upper atmosphere of Earth and come back down to spread long distance), but I find it difficult to believe that anything could grow and divide at such low temperatures. That seems chemically and thermodynamically impossible with the microorganisms that we know of now. The leaves the possibility of evolution to some type of life we don't know about, but again, evolution requires geological time scales, and the trip from here to Titan, presumably in a dormant state, would not allow sufficient time or for that or the multiple rounds of natural selection. Neat idea none-the-less, but not enough incidents to play the probability game properly.

  • Purpul Sulphur Bacteria (Score:5, Interesting)

    by Kozar_The_Malignant (738483) on Friday March 17 2006, @07:25PM (#14945986)

    >chemistry is very different from Earth's.

    There are some Earth life forms with some pretty weird chemistry. One example is purple sulphur bacteria. Instead of using water as a reducing agent, they use hydrogen sulfide. This is oxidized to elemental sulphur and sometimes on to sulphuric acid. Heck with this water/oxygen thing. These are a very old group of organisms.
    • There's all kinds of weird bacteria on Earth, including extremophiles that consider boiling water to be a little on the chilly side. Cold-water corals can survive quite nicely in the North Sea and I've heard of them off the coast of Alaska. Although not a bacteria, the "ice worm" discovered in Washington State can only live in below-freezing conditions. They explode at higher temperatures, apparently.

      Combine all this with being able to digest unconventional materials - your example was sulpher - and you've

    • I saw a movie about that. Ripley escaped with the cat, but none of the other did. ;-)

  • Dinosaurs in Space (Score:3, Funny)

    by truckaxle (883149) on Friday March 17 2006, @07:28PM (#14945995) Homepage
    Could there possible be bits of dinosaur DNA orbiting around in the deep freeze of the solar system? or would high energy particles quickly destroy the DNA? Well if anything sounds a like a great mechanism for a movie. Man finds chunks of frozen desiccated dinosaur. Man brings back Dino DNA to earth and splices DNA with that of frogs, Man recreates Dinosaur species, Dinosaur eats Man. Appologies to Ian Malcolm...
  • About 100 have reached Jupiter's moon Europa...
    Of course, that's 100 simulated Earth rocks reaching a simulated Jupiter's simulated moon Europa. Usually I'd rag on the New Scientist for yet more crappy, sensationalist reporting, but this was clearly the submitter's fault.

  • One thing - (Score:3, Insightful)

    by Kittie Rose (960365) on Friday March 17 2006, @07:59PM (#14946093) Homepage
    People are also only pointing out animals we know exist being on those boulders. It's entirely possible there were many more species hundreds of millions of years ago that were as resiliant as the "Water Bear" towards harsh conditions, but suffered some other short coming that lead to their extinction on Earth.

    • Re:That Would Be A Very Tough Bug (Score:5, Interesting)

      by LiquidCoooled (634315) on Friday March 17 2006, @05:51PM (#14945551) Homepage Journal
      How about this [pnl.gov]:

      Named the World's Toughest Bacterium by the Guinness Book of Records, the large red spheres of Deinococcus radiodurans (translation: strange berry that withstands radiation) can not only endure acute radiation doses of up to three million rads but more remarkably, can actually grow when exposed to radiation continuously.

      You really don't want to meet this in a dark alley, however with that much radiation, I doubt it would be dark for long.
    • Bacteria survived several years on the lens cap of a camera left on the moon. It's resilient stuff!
    • "The team ran computer models of such giant impacts, estimating that each would send about 600 million boulders into space to orbit the Sun. Some of those launched at relatively high speeds - faster than 6 kilometres per second - got as far as Jupiter and Saturn in about a million years.

      In the simulations, about 100 of the boulders from each impact reached Jupiter's moon Europa. "

      UNFOUNDED I TELL YOU!!! They're just pulling these numbers out of thin air!! Ludicrous!!!

      The whole thing was a simulated what-if,

      • Re:R.T.F.A. (Score:5, Informative)

        by Karzz1 (306015) on Friday March 17 2006, @06:09PM (#14945658) Homepage
        "The whole thing was a simulated what-if, something made abundantly clear from start to finish. They "Know" these impacts happened and at precisely what speed because IT WAS A FEKKING SIMULATION, DAMN IT!"

        This is true, but also stated in the article "The cause of such impacts would be comets or asteroids between 10 and 50 kilometres wide, Gladman told New Scientist: "The kind of thing that killed the dinosaurs."" meaning that these numbers were not just pulled out of an orifice but rather based on actual historical earth impacts. Is it proof that these rocks made it to Titan (and in the numbers estimated)? No. But it is probable. The last line of the article sums it up nicely; "Gladman agrees that life may be unlikely to survive once on Titan. But he says major impacts may have happened "tens of times" throughout Earth's history and that these could have sent Earth rocks to other solar system bodies. "I just set out to answer this question: is it possible to get something there?" he says. "The answer is yes."". Draw your conclusions from there.

    • Your points are moot. (Score:5, Insightful)

      by technoextreme (885694) on Friday March 17 2006, @05:58PM (#14945606)
      That's a tough bug. The temperature isn't such a big deal and time isn't either, as there are bacteria found in Antarctica which were left over from when it was more temperate. Tough bugs, sure, but traveling through space also means withstanding the full bore radation of Mr. Sun, with no atmosphere to protect you. I'm not sure I want to meet one of these in a dark alley. From the article: "'I thought the Titan result was really surprising - how many would get there and how slowly they'd land,' Treiman told New Scientist. 'The thing I don't know about is if there are any bugs on Earth that would be happy living on Titan.' Titan's surface temperature is a very cold -179C and its chemistry is very different from Earth's."
      http://www.space.com/searchforlife/seti_saltlovers _050721.html [space.com] First thing I searched for is bacteria and radiation lovers. They are life forms on earth that can survive this type of conditions. Also, it is a fact that bacteria survived on the moon for three years during the Apollo missions.
      Ok, I'll bite, how do they know they came from Earth rather than, say were asteroids? A lot of asteroids look like they broke away from something as they're irregular in shape, perhaps there's other likely origins. But this has gone from 'could have' to did without convincing me. After all, we see supposed martian rock on earth. Who's really to say that those martian rocks broke from Mars, rather than are the stuff Mars is made up of and some of it landed on Earth, or some other theory.
      Ummm.. It's a simulation. They didn't actually discover the rocks. They didn't see any evidence. They just did the math. All they said is that they know that this stuff got shot into space and they figured out that it can reach Titan.
    • From BoingBoing: [boingboing.net]
      Now here's the thing I really like about tartigrades. They are apparently the World's Toughest Animal. You can shoot them into space, take them to the deepest ocean depths and let them go, deprive them of air, water, and food for years and they don't care. Send them into the core of nuclear reactor. They'll be fine.
    • About 100 have reached Jupiter's moon Europa - but they landed at 24 miles/sec.

      This bit seems wrong. The escape velocity of jupiter from the surface of Europa is not 24 miles per second. Not even close. IIRC the escape velocity from the surface of Jupiter is less then 60 km/s. Rocks should be able to arrive on elliptical orbits with zero relative velocity at Jupiter.

      Even so, without an atmosphere to slow them dowm, rocks will make quite a bang at Europa. Much less on Titan.

    • Re:That Would Be A Very Tough Bug (Score:5, Funny)

      by iamlucky13 (795185) on Friday March 17 2006, @06:15PM (#14945685)
      Ok, I'll bite, how do they know they came from Earth rather than, say were asteroids?
      Because they said they came from earth when they created the computer model the article is talking about. One of the nice things about computer models is it's relatively easy to control external effects, like asteroids.

      Solar Billiards - v1.3.11
      Please input the following earth-impactor parameters for your simulation

      Impactor diameter (m): 5000
      Impactor velocity (m/s): 12000
      Ecliptic Declination (deg): 7.3

      Please input the following solar system parameters for your simulation

      Target diameter (km): 4000
      Target solar altitude (AU): 15
      System asteroid density (objects/AU^3): 0

      Click start to begin

      Calculating Trajectories...Done

      Results:
      Total impacts of earth origin: 107
      Impacts of non-earth origin: 0

      Congratulations! Impact count greater than 100! Click here to redeem your free iPod!

    • Re:That Would Be A Very Tough Bug (Score:5, Informative)

      by Decaff (42676) on Friday March 17 2006, @06:15PM (#14945687)
      Tough bugs, sure, but traveling through space also means withstanding the full bore radation of Mr. Sun, with no atmosphere to protect you. I'm not sure I want to meet one of these in a dark alley.

      You probably already have. There are bacteria that can survive and even grow exposed to levels of radioactivity found in some parts of nuclear reactors. It looks like some of these bacteria also live in the human stomach.

      The thing is, harsh environments and to things like drying out can cause DNA damage, and the same incredible repair mechanisms that help some species to survive those allow them to survive intense radiation.

      Incidentally, bacteria surviving to reach Titan is not that interesting - far more exciting is the possibility of them reaching another moon of Saturn - Enceladus, which probably has liquid water.

    • Re:I'm scared (Score:4, Insightful)

      by Expert Determination (950523) on Friday March 17 2006, @06:47PM (#14945830)
      The fact that we have determined these things hit Earth makes them no more likely to hit Earth. I say we carry on ignoring them like we did before anyone had any clue such a thing could happen.
      • "Is it just me, or does the idea of meteors kicking stuff *off the earth* not pass the laugh test?"

        Only a tiny fraction of the original mass need reach escape velocity to allow bacteria to escape (they're fairly small compared to some of these objects after all). If the moon formed from ejecta from a large impact (as seems to be the case), is it so hard to believe that objects a tiny fraction of that size reached escape volocity?
    • And the decelleration and temperature resulting from the crash landing is substantially different from the acceleration and temperature resulting from an explosion that caused the rock to exceed escape velocity in the first place?

      Yep.

      Not "the explosion" itself, but the environment felt by the launched rock, which could be lifted relatively gently by the rocks and soil under it, as the atmosphere above it is lifted out of the way / along with it by it and the neighboring material.

      It isn't the stuff that gets HIT by the asteroid/comet/whatever that get's launched. It's the stuff on and near the top of the ground nearby that gets lifted by the violence spreading out below it.

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