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Earth Life Possibly Could Reach Titan 237

Posted by Zonk
from the bacteria-with-heavy-coats-now-thriving-there dept.
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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Earth Life Possibly Could Reach Titan

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  • by LiquidCoooled (634315) on Friday March 17, 2006 @06:45PM (#14945511) Homepage Journal
    Lawyers.

    They can survive anywhere.
  • Airborne bacteria? (Score:5, Interesting)

    by Bahumat (213955) on Friday March 17, 2006 @06:47PM (#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?
      • by jd (1658) <imipak@yaCOLAhoo.com minus caffeine> on Friday March 17, 2006 @09:16PM (#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.)

        • by Decaff (42676) on Saturday March 18, 2006 @12:58AM (#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.
          • You fail to understand the magnitude of these impacts. Hint: rifle-bullets do not impact at 24 miles/second, they leave the muzzle with something between 0.2 and 1 miles/second (old pistol to kinetic-kill armour-piercing), the impact-speed is even lower due to air-resistance. (depends on distance though)

            24 miles/second is roughly 50 times that speed, so the impact-energy would be roughly 2500 times higher.

            So, it's sorta like saying that humans are hardy creatures, they can easily survive a fall of 1 foo

        • 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
          • DNA replication is affected by ionizing radiation, that is known. What those experiments found is that DNA itself is resilient. So if the bacteria is not reproducing, it is ok. Some can even fix their DNA and reproduce on a hight radiation evironment.

            And the evolution is much more dependent of genetic recombination* than on mutations. That is why all known life forms (and virus too) do it (as far as I know at least, IAN a biologist).

            * On our case, sex. But different creatures use different strategies, bac

      • If you take a random bacteria and dump it next to a sulfur vent it will probably die. The process needs to be gradual enough to allow the bacteria to adjust or enough bacteria need to get there for one to randomly survive. On Earth both of those could happen, while an asteroid transfer would have neither really.
      • 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
      • "If they can survive the extremes of air, ocean depth, and heat, why not those of cold and darkness?"

        First they have to survive the sudden blast of extreme heat and pressure caused by an asteroid impacting with enough force to send chunks of rock large enough to not burn up on the way out of the atmosphere flying away at speeds greater than escape velocity.
    • by isomeme (177414) <cdberry@gmail.com> on Friday March 17, 2006 @08:45PM (#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? I grant that temperature extremes are an inhibitor, but 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."

        *shrug* Guess I should have studied more science and read less science ficti

        • 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

        • by cagle_.25 (715952) on Saturday March 18, 2006 @05:26PM (#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.

  • 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 @06:56PM (#14945591) Homepage
    Tartigrades, otherwise known as Water Bears [wikipedia.org] might survive such a journey. They're the cutest microscopic animals ever!
  • by Anonymous Coward on Friday March 17, 2006 @06:56PM (#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 @06:58PM (#14945607)

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

  • by Ranger (1783) on Friday March 17, 2006 @07:09PM (#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!

  • ... but they landed at 24 miles/sec. 'This must be rather frustrating if you're a bacterium that survived launch from Earth ...

    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?
    • 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?

      If you start with a big rock under the surface close to an impact point on Earth, most of the rock will be damaged while being ejected into space but a few small bits in the centre may survive intact. But these bits won't be able to survive an impact on Europa.

    • Yes. It has probably been slowed by gravity from various objects, and if they're lucky, they might be moving at a small relative velocity to thier impact site due to orbit directions and such.
    • by Ungrounded Lightning (62228) on Friday March 17, 2006 @08:30PM (#14945998) Journal
      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.
  • Well... (Score:3, Funny)

    by AWhiteFlame (928642) on Friday March 17, 2006 @07:40PM (#14945794) Homepage
    Well, as long as they had an intel processor with them, they've got plenty of heat to survive.
  • by GroeFaZ (850443) on Friday March 17, 2006 @07:41PM (#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?
  • by Anonymous Coward
    Ok this time we compromised! We converted the 40 km/s of the article into 24 miles/sec, but kept the -179C unconverted.

    For our next science article we will do the opposite. When we think you are ready -- but only then -- we won't convert anything and you'll be on your own.
  • The rocks being ejected from our atmosphere are going to be heated red-hot or more on the way out. How likely is it that bacteria that can survive that can also survive the cold on Titan? It seems like it's asking a bit much for them to be resistant to both red-hot heat and freezing cold. Does anybody know how likely that is?
    • Launch isn't like reentry.

      The mass of material lifted from beside the strike and above what will be the crater goes up with the atmosphere surrounding it and doesn't experience the sort of extreme heating you're supposing.

      It's still pretty abrupt accelleration (which bacteria handle pretty well, especially if embedded in something of a similar density). But the rock isn't plowing through dense air that is at a speed differing from its own by something in excess of escape velocity. The air gets launched, t
  • by posterlogo (943853) on Friday March 17, 2006 @08:17PM (#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.

  • by Kozar_The_Malignant (738483) on Friday March 17, 2006 @08:25PM (#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. ;-)
  • by truckaxle (883149) on Friday March 17, 2006 @08:28PM (#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...
    • I could imagine something like a geode crystal managing to stay warm and moist in outer space, hell we could discover at the very heart of Halley is an entire ecosystem which comes alive once every 76 years like flowers in the desert.

      We just never get close enough to see it bloom.
  • by HorsePunchKid (306850) <sns@severinghaus.org> on Friday March 17, 2006 @08:33PM (#14946008) Homepage
    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 @08:59PM (#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.
  • Then it's entirely plausible that life on Earth came from places other than earth.

    Of course this plays right into the hands of the fundamentalists. In their view we were put here by their God. But I'm not one of His people - I'm one of the others mentioned in the good book. But I'm talking extraterrestrial here, not metaphysical.
  • Put a bitch in heat on Titan, and I guarantee a dog will stud Titan into being a giant kennel in no time. Life is incredibly persistent.
  • All these worlds are yours except Europa. Attempt no landing there.
  • by dodobh (65811)
    About 100 have reached Jupiter's moon Europa - but they landed at 24 miles/sec

    All these world's are yours, except Europa. Do not land there.

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