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Space Science

Evidence of Bacterial Life on Europa 71

Posted by timothy from the or-it-could-be-the-flush-of-health dept.
AaronW writes: "According to this article at newscientist.com, the rosy color of Europa may be caused by bacteria. Apparently the previously unexplained infra-red signature matches that of extremophile bacteria found here on Earth."
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Evidence of Bacterial Life on Europa More

Evidence of Bacterial Life on Europa

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  • All these worlds are yours... (Score:4, Interesting)

    by Deagol ( 323173 ) on Tuesday December 11, 2001 @05:38PM (#2689299) Homepage
    except Europa.

  • Just as good, eh? (Score:3, Insightful)

    by Anonymous Coward on Tuesday December 11, 2001 @05:50PM (#2689373)
    Preliminary results show that all three species, the ordinary gut bacteria Escherichia coli, and extremophiles Deinococcus radiodurans and Sulfolobus shibatae, are just as good at explaining Europa's IR spectrum as the salts.

    Except that the salt theory doesn't rely on extraterrestrial life being created on one moon completely inhospitable to life in the middle of nowhere.

    • Re:Just as good, eh? (Score:3, Interesting)

      by Lars T. ( 470328 )
      Do you know what a "Black Smoker" is? Do you know that their surroundings are "completely inhospitable to life in the middle of nowhere"? And that they may have been the places were life on earth started?

      Try this [dhs.org], and this [amnh.org], and this [nhm.ac.uk]. (Just a little googleing ;-)

      • I wouldn't call liquid water "completely inhospitable to life", especially since the ecosystems around each smoker are more or less the same; i.e. organisms are successfully swimming some distance through the cold water to get there. There's no evidence of anything like different DNA coding systems to indicate that life began at black smokers. The big problem with them is that they only last 50-100 years, IIRC. Certainly not the millions of years that we expect is necessary for molecules to get together and spontaneously start life. Maybe Europa's tides keep its vents open longer, but your statement about Earth has a lot going against it.
        • Liquid water, that is either very hot (near the smoker) or quite cold (further away), at very high pressure several thousand feet below sea level, no light, instead a lot of minerals and salts that are toxic (or at least harmful) to "life as we know it". Just a couple of decades ago scientist believed that to be "completely inhospitable to life", just like the AC thinks about Europa - with the difference that he is probably not a scientist.

          As for the rest, read the first site I linked to, and the other articles found there - The Origin of Life [dhs.org].

    • Re:Just as good, eh? (Score:1, Interesting)

      by Anonymous Coward
      Ya know... when life started on earth... it was pretty damn inhospitable here too. There was no oxygen, no water (...oxygen), so our standards of "inhospitable" aren't universal... I mean, there are bacteria in your ass, and who can think of a more inhospitable place than that?!?
      • Sorry, but wrong (to quote a cartoon I recently saw). There was no molecular oxygen in our atmosphere, you're bang on. But that was GOOD for life. Oxygen is lethal to a lot of life, and was lethal to most organisms that have ever existed on Earth. The oxygen in our atmosphere only built up about 2 billion years ago. At that time, a lot of organisms would have perished. We're just decendent form the ones that adapted. But oxygen is by no means necessary for life. Lack of it is probably more helpful than harmful, since oxygen tends to react with organic molecules to their detrement.

        As for water... dead wrong. You'd do well to do a bit of research on that point. The early Earth would have had to have had water. Not having molecular oxygen in our atmosphere has nothing to do with having or not having water. After all, we have all kinds of oxygen in our rocks: it's the singly most abundant element in the crust.

  • Occam's Razor (Score:4, Insightful)

    by Catiline ( 186878 ) <akrumbach@gmail.com> on Tuesday December 11, 2001 @06:20PM (#2689617) Homepage Journal
    Glenn Teeter from the Pacific Northwest National Laboratory in Washington state says bacteria aren't the simplest explanation for Europa's spectrum.
    Yet...
    No one has managed to come up with the perfect mix of [mineral] salts to explain all of Europa's spectrum.

    Okay boys, settle down and apply a little common sense here. If the experiment works, let's ask ourselves why. At the least, it proves Europa has all the right elements (pun intended, for sure) for life to form.

    Of course we still would want to go and see for ourselves, just to be sure. But let's make sure the astronauts pack lots of penicillin, just in case. {grin}

    • Re:Occam's Razor (Score:5, Insightful)

      by re-geeked ( 113937 ) on Tuesday December 11, 2001 @06:54PM (#2689834)
      But which argument does the Razor favor?

      Is it simpler to believe that a mix of salts causes both the IR spectrum and the visible coloration, or is it simpler to believe that some bacteria cause it?

      We've never seen life off the Earth, but we've also never seen a lack of life in livable conditions on Earth.

      We've never seen bacteria having an effect on another celestial body's spectrum, but we've never seen the combination of salts (even on Earth) that could cause this spectrum either.

      I would grant that it doesn't meet Sagan's more stringent requirement that "extraordinary claims require extraordinary proof."

      I also agree there's only one way to be sure...

      • Re:Occam's Razor (Score:2, Insightful)

        by Catiline ( 186878 )
        Neither argument is favored. Occam's razor favors the hypothosis that organic chemicals are the cause; whether they form living cells or not is yet to be determined.

      • Re:Occam's Razor (Score:4, Insightful)

        by JabberWokky ( 19442 ) <slashdot.com@timewarp.org> on Tuesday December 11, 2001 @08:32PM (#2690356) Homepage Journal
        We've never seen bacteria having an effect on another celestial body's spectrum, but we've never seen the combination of salts (even on Earth) that could cause this spectrum either.

        Have we even ever *seen* salts on anything other than Earth - I mean verifiable through other than spectral analysis. Quite simply, we really know *very* little about even our neighboring planets. Occam's razor becomes utterly useless when you're dealing with neigh-complete unknowns; there's no way to choose the most simple explaination when you have only one example that you know. Give me the total, verified chemical makeup of 5,000 planets near a star with a similar stellar sequence, and *then* start saying you can predict the most simple hypothesis.

        Hell, we've sent probes to Mars, and don't know if there was life there. We don't even know for sure that there is water ice on our own moon of significant quantities.

        (As an aside that will probably provoke more replies than the main text, does anyone else get fucking pissed at people who are unable to realize that humanity is *really* in it's infancy, and we've barely cracked the egg? Ad Astra Per Aspera, but the Eagle has landed, and we're on our way out.)

        --
        Evan

        • We know how something about how improbable it is that life exists, at least as far as we can tell. As intelligent organisms, we cannot accurately calculate the probability of life being spontaneously created because we have never done it ourselves, EVER.

          Conversely, we know how to make many different kinds of salts. Even though we don't know the precise chemical composition that could create this spectrum, we are much closer to causing that by randomly combining chemicals.

          Occam's Razor therefore dictates that the most probable event is NOT life. Here's a similar hypothesis (another piece of data with a theory that has an incalculably low probability of occurance):

          I don't know where my parents are, but I saw some strange, oddly organized patterns in the aurora borealis today. My parents must be on the sun, sending me a message.

          • Re:Life (Score:3, Interesting)

            by JabberWokky ( 19442 )
            We know how something about how improbable it is that life exists

            that's just it - we *don't* know that there isn't DNA scattered out there in the interstellar void, like McDonalds wrappers next to a highway. We might go to Mars and find blooms of life all over the planet... might find it on the Moon. Hell, Jupiter could be raining down thousands of tons of organtic, replicating lifeforms in it's atmosphere. There could be life on every major body in the system.

            Or there could be life on only one. We don't *know*. We haven't been there - we've only tossed low resolution (but well calibrated) cameras to fly past them at high speeds, and landed in a few of the most boring spots we could find on our own moon. Other than that, we sent a few landers to Mars and Venus, which didn't do much either.

            And as far as even *organized* life goes, we don't know that much - we can be pretty sure of Mars due to the landers, and a few without any atmosphere... but in the oceans of Europa, the atmosphere of all the gas giants...

            I'm not going to tell you that there *is* life there... but I defy you to show me that it *isn't* there. The dataset is insufficient to predict the most likely scenero.

            As intelligent organisms, we cannot accurately calculate the probability of life being spontaneously created because we have never done it ourselves, EVER.

            Got news for ya, pal - there's plenty of stuff we can watch every day that we can't do. That dosen't mean it dosen't happen. We've only been writing it down for about 6000 years, and keeping decent records for the past few hundred. We don't even know how *we* arose, when or where. And from fossil records, it looks like life has risen and fallen on our own planet many many times (and I'm talking "make it to the multicelled stage, and then fall back", not dinosaurs - they are our brothers in comparison). Once complex lifeforms (and sex) caught on, life got really diverse and really pervasive on this planet. If that didn't happen, Earth would look much like - well, what we can see of the other planets and major moons.

            --
            Evan

            • Despite all of our informed attempts to throw what we think are the right chemicals (i.e. all of the ones that make up life), we have not succeeded in creating it. What can we conclude from our search? Considering the sheer amount of searching we have done in order to attempt the creation of life, we can assume that it requires extremely delicate (i.e. extremely improbable conditions). Were this not the case, we would have found the right combination to create life already.

              This is not unlike a lot of the things that we don't know how to do. We can say something about the difficulty of solving any problem (modeling any phenomenon) by examining and dismissing the most likely possible solutions/theories. This is the basis of a lot of the field of statistics, and part of the basis of Occams Razor: the past knowledge should be considered when evaluating the future (in this case, our past experience shows that it is easier for to generate salts that have unique properties than it is to create life).

              You disagree? I should never consider that the probability of something that has never been observed should be considered astronomically low? Then I better start wearing a helmet to be ready for when the sky falls.

              As an aside, I think that the probability of life occuring spontaneously is too high for it to exist at all in a universe this small or this young. Given our current estimate of the probability of the formation of life, and our guess of the age and size of the universe, the odds that life would already exist are incalculably high. I believe we must have been created.

              • Re:Life (Score:4, Insightful)

                by JabberWokky ( 19442 ) <slashdot.com@timewarp.org> on Thursday December 13, 2001 @03:57AM (#2697968) Homepage Journal
                Considering the sheer amount of searching we have done in order to attempt the creation of life, we can assume that it requires extremely delicate (i.e. extremely improbable conditions). Were this not the case, we would have found the right combination to create life already.

                We have failed to create sustainable fusion as well. Go out on a cloudless sky, and you will see as many arguments against your logic as there are stars in the... well, you get the idea. Just because *we* cannot do something doesn not mean it is not dirt common as far as the greater universe is concerned.

                our past experience shows that it is easier for to generate salts that have unique properties than it is to create life

                And yet we cannot create a mixure of salts to match this signature - the only thing that does exist that matches are bacteria. I would say that you are arguing for the opposition.

                I should never consider that the probability of something that has never been observed should be considered astronomically low?

                Something that has never been observed in a domain that has never had more than casual observation. If I tell you that there is a set of 10,000 numbers, and one is 89.63, what can you predict of the set? We know what color Europa is (in a few different spectra), and what it's surface looks like on a very low resolution - the kind of resolution that would miss life on Earth. That's it.

                Given our current estimate of the probability of the formation of life, and our guess of the age and size of the universe, the odds that life would already exist are incalculably high.

                And you would argue statistics with me? You are accepting probabilities that are utter guesses. Until the past few years, we had not even known if there were any other solar systems with planets. How can you propose the probability of something when you have no idea of the basic postulates to form an opinionated guess upon? Ask a dozen different scientists what the probability of life elsewhere in the universe is, and most will couch it in very measured words - the data is just not available.

                I believe we must have been created.

                A pointless statement in this debate - faith is not in question here (and a belief based on insufficient data is one founded on faith). What is in question is the relative probability that life is on Europa. I merely state that we do not yet know how common life *is*, and thus cannot predict the most simple answer.

                --
                Evan

                • Something that has never been observed in a domain that has never had more than casual observation.

                  The probability of life existing on Europa is necessarily less than the probability of the formation of life in general, of which biologists have been doing quite a bit more than a casual study. As I said, we have REALLY tried to make it happen.

                  You gave the example of nuclear fusion. In this case, you are referring to a phenomenon that we don't have the capability to create. This is something quite different; if we could bring a large enough mass to a high enough temperature and pressure, it would fuse on its own. Finding out how to create life is more like solving an NP hard problem - we have all of the necessary components, since we know the exact chemical makeup of life and under what conditions it is capabile of subsisting. All that is required is that we try all of the finitely many (though extremely large) combinations of reactions that would be necessary to produce life. We have tried a small but significant subset of these combinations - it is significant because we have eliminated classes of solutions through our efforts, not merely single solutions. From this, we can say that the probability of spontaneous creation is low, though we may not agree as to how low.

                  Just because *we* cannot do something doesn not mean it is not dirt common as far as the greater universe is concerned.

                  Let me extend my point to be more inclusive: if we can find the probability of an event in a domain, and have no evidence to the contrary for other domains, Occam's Razor would dictate that this probability also holds for other domains.

                  In other words, if the simplest solution to any problem is most likely the correct one, then what we observe about things on earth also holds for outer space unless we get other data, as is the case for the existance of stars.
                  Life could be dirt common, but it would not be wise to assume that this is the case unless you believe that Occam's Razor is a fallacy.

                  And yet we cannot create a mixure of salts to match this signature - the only thing that does exist that matches are bacteria. I would say that you are arguing for the opposition.

                  That's not necessarily true. We HAVE NOT created a mixture of salts that match this signature. This does not mean that doing so is impossible or even improbable for us. We've only had the data a short time, and there are more than a few combinations to try to figure out what a correct salt would be to produce such a spectral signature. There may have been no reason to create such salts in the past.

                  • Re:Life (Score:3, Interesting)

                    by JabberWokky ( 19442 )
                    The probability of life existing on Europa is necessarily less than the probability of the formation of life in general

                    No, because we do not know that life first formed on Earth - the "space seeding" concept grows more likely when you consider that ALH 84001, while it can not be shown to have definitively brought life from Mars, is pretty accepted to have been *capable* of doing so. Life, being small replicating units, is quite capable of having strewn itself across space. Who knows - maybe this area of space is covered in DNAish life, and other areas have other forms of replicating instruction sets - possibly in other phases of matter.

                    if we can find the probability of an event in a domain, and have no evidence to the contrary for other domains, Occam's Razor would dictate that this probability also holds for other domains.

                    Look at the domain we do have. Earth is covered in life. By your logic, every other unexplored domain would be similar. Certainly by your logic, the *existing* item that demonstrates the phenomina would be more likely than the theoretical one, right? The salts are theoretical, whereas multiple examples of bacteria exist, which *also* satisfy both the visible color and color distribution.

                    But *I'm* not saying it's life (note that I make this clarification in each post) - I am saying that one can *not* derive the necessary probabilites from our observation to date. We have one planet that we know details about, and extrapolating from that one planet is idiotic, whether you use that extrapolation to say "there's got to be life everywhere" or "We're not pulling in Martian HBO, so there's no life out there". The other bodies in the system are radically different, more extreme than the most extreme conditions on our planet. We have no idea what chemical reactions occur in some of the conditions that exist out there, let alone what *is* out there.

                    Years ago, they thought the seafloor was a dead zone. Then they found it was covered with oases of life (and yes, I looked that plural up). The point is not that life was there, but that, given all that we knew about life, it "couldn't logically have been", and it was. Now you say that Europa "can't logically have" life. You don't know, and have absolutely *no* detailed observations of any other planet than Earth, and thus cannot extrapolate. Occam's Razor cannot work when we don't *know* what the most simple explaination is - we don't know what is common even in our own solar system.

                    We HAVE NOT created a mixture of salts that match this signature. This does not mean that doing so is impossible or even improbable for us. We've only had the data a short time, and there are more than a few combinations to try to figure out what a correct salt would be to produce such a spectral signature. There may have been no reason to create such salts in the past.

                    We HAVE NOT created a mixture of chemicals that create life. This does not mean that doing so is impossible or even improbable for us. We've only had the data a short time (Since Watson and Crick figured it out on February 28, 1953 - we've known about fusion prior to 1938), and there are more than a few combinations to try to figure out what a correct reaction would be to produce such a structure as DNA. There may have been no reason to create such chemicals in the past.

                    And we have already created simple chemicals that reproduce given raw materials - DNA is more complex, but not impossibly so. If, tomorrow, someone created DNA in a lab, would you say that there might be life on Europa? What difference would it make? Absoluetly none. The current capabilities of human technology does not define what the universe is capable of containing. Do not confuse technology with science.

                    --
                    Evan

              • You disagree? I should never consider that the probability of something that has never been observed should be considered astronomically low? Then I better start wearing a helmet to be ready for when the sky falls.

                If you're talking about the so-called firmament falling, that has been shown to be impossible. If you're talking about meteors, those have been observed. Extraterrestrial life has never been observed, but has not been proved impossible. And the amount of data we have is not enough to calculate the likelyhood of life elsewhere.
  • I'd like to believe that there's life on Europa, but since the bacteria couldn't survive surface conditions, I find it highly unlikely. Then again, there are subterranian life forms here on Earth, so I guess it's possible. It sounds like a better theory than the salts, at any rate.
  • I'm not an expert in this, but there's got to be some rules and explanations about life where there is no atmosphere.

    I kinda thought that there had to be some atmosphere (perhaps at one point Europa had a higher one?) in order for any form of life to exist. I could be wrong, because this is just a guess, so if someone would like to enlighten me, please do.

    • Re:Life without atmosphere? (Score:1, Interesting)

      by Anonymous Coward
      If there is a liquid zone underneath the ice, it could be considered an atmosphere (well, you know what I'm saying).
    • I'm not an expert in this, but there's got to be some rules and explanations about life where there is no atmosphere.

      Speaking theoretically, I don't see why there would have to be an atmosphere. For example, to most of the sea-dwelling creatures on Earth, it just as soon not have an atmosphere.

      • Hmm...
        Thats not strictly true. Most [well depending on how you define most] of the sea life we know of does consume O2 dissolved in the water [ie fish, gills]. If there was no atmosphere above the water there would be no such organisms.

        That said there are lots of anearobic bacteria that would even be slightly better of underwater if the atmosphere wasn't there.
    • Honestly, we *have no clue.* Well, maybe a couple of little clues. But we have one point of reference for *all* our theories of life. And one point is not enough to draw general conclusions.

      Life could exist everywhere. Our universe tends to self-forming complex structures (suns, planets, galaxies, black holes, nuetron stars, crystals (snowflakes and such, for instance), language, radiators, jam, etc). So there's no reason life couldn't exist on the surface of neutron stars ("Dragon's Egg," by Robert Forward), or in the heliosphere of our own sun ("Sundiver," by David Brin) or in the depths of space (the known space universe of Larry Niven, for instance).

      Hell, it was only 20 years ago we were shocked to discover bacteria and worms in the "lifeless" regions of our own earth.

      The fact is, we have some ideas about how life began on earth (many different, mutually-exlusive theories exist), but we don't know. And so how can we know all the various conditions under which life can begin? Or even *can't* begin?

      We are ignorant savages that believe we know what we are about. Like a 16-year-old, we think we know everything we need to know; but in reality, we are naive and untutored. That will change, I have no doubt. But until that point, we have a body of knowlege we are sure about, and a body of knowlege we *think* we are sure about (but which is completely bogus), and a whole bunch of knowlege we don't even know we lack.

      That's what's so cool about the universe.

  • Eh... (Score:3, Informative)

    by global_diffusion ( 540737 ) on Tuesday December 11, 2001 @07:40PM (#2690094) Homepage
    It's New Scientist. It sounds nice and could be a valid theory, but until we have more detail we won't know. This is what everyone wants to hear about Europa (because of it's oceans), but that doesn't mean that this is more than a guess.

  • More wacky reporting from New Scientist (Score:4, Insightful)

    by HorsePunchKid ( 306850 ) <sns@severinghaus.org> on Tuesday December 11, 2001 @07:46PM (#2690123) Homepage
    See my previous rant [slashdot.org]. This seems to be yet another case where a writer for this news source has put their own sci-fi spin on what is otherwise a very unremarkable bit of information. Take five minutes to read and think about the points in this article, and you'll be sorry you did. It's chock full of conceptual holes, misunderstandings, and unfounded extrapolations into the news-bite realm of absurdity. Please stop posting this yellow journalism.

    • Re:More wacky reporting from New Scientist (Score:4, Funny)

      by caffeinated_bunsen ( 179721 ) on Tuesday December 11, 2001 @11:09PM (#2691205)
      New York Times : National Enquirer :: Nature :

      A. Annals of Physics
      B. New England Journal of Medicine
      C. New Scientist
      D. None of the above

      This story provides yet more evidence for C.

    • Hear, here!

      I used to read the NS a bit, it is entertaining. But so is Harry Turtledove and Dan Simmons. I'm not passing that off as reality.

      In the department I used to be in, we'd have some cool arguments over what was going on in NS articles... it was usually 6 dudes saying "that's bullshit", and then 4 dudes saying, "well, if it were true, then we could build, etc., etc., and that would be cool". Very cool conversations, sometimes, but, frankly, worthless from a scientific point-of-view. Good for lunch conversation, tho'...

  • remember Mars, but still interesting (Score:3, Interesting)

    by Sprunkys ( 237361 ) on Tuesday December 11, 2001 @08:33PM (#2690360)
    let's us not jump to early conclusions; i always tend to find these kind of articles very hope-giving while they are often very inconclusive. A while ago we could read about waterflows on mars (with pictures!) that later turned out to be carbon?dioxide? jets if i remember correctly. Those were some nice pictures, don't get me wrong and this article sure lightens up the discussion of extraterrestial life (not intelligence, life, note the difference please) that could possible be related to earth life (asteroids and all) which could give us some insight in the development of earth-life.
    So, interesting, but don't get your hopes up too much :)
  • One of the big reasons we're hearing more of this is that since the fossil bacteria mars meteor find there has been a lot more focus on Astrobiology. NASA Ames has a Astrobiology Academy [nasa.gov] that is sort of a Space Camp for the 18 to 25 year old crowd that grew up wanting to go to Space Camp (that's us).
    There are also a lot of Collegiate program's like Penn State's [psu.edu] and some new peer reviewed astrobiology journals.
    Sort of a case of we find what we look for. Makes you wonder what the SETI people could do with more funding.

  • Fits Are Not Unique (Score:5, Interesting)

    by CheshireCatCO ( 185193 ) on Tuesday December 11, 2001 @10:58PM (#2691155) Homepage
    Oddly, I was just having an argument with the head of CU's astrobiology institude about this point. Fits to surface spectra are seldom unique. It's a pain in the butt, be we can't even identify the minerals on Mars uniquely some of the time. Europa is worse. Not only do we not know the chemistry as well (rocks is rocks, and we have plenty of those on Earth), but the conditions are hard to reproduce. Temperatures of around 100 K, almost no surface pressure and a harsh radiation environment.

    If you do a little digging (check back issues of Science magazine), you'll notice that there are already two theories about the mysterious absorber on Europa. There's McCord's salts theory and there's the sulfuric acid theory (put forward by Carlson). We can't distinguish between them right now. Adding another potential absorber to the fray doesn't really fundementally alter that we just can't tell right now what's down there.
    • the conditions are hard to reproduce. Temperatures of around 100 K, almost no surface pressure and a harsh radiation environment.
      So if we send a probe there, it'll come back covered in superbacteria that will wipe us all out, is that what you are saying? Disband NASA now, it's too dangerous! :-)
    • They have the same problem trying to figure out where the stains in my tub are coming from.
  • ...To me the likelyhood of life on Europa depends upon the availibility of [principaly] heat and minerals. In deep sea sulphur vents life positively teams [a recent BBC documentry with some rare footage revealed three layers of life sitting atop these vents, with the white crabs on top standing shoulder to shoulder].

    Basically my question is whether an object of europa's size has sufficient internal heat to provide lifes principal energy. [its about the size of mercury??]. I presume that the ice layer will filter cosmic rays effectively, there will be minimal sunlight etc, so we need a primary energy source. If there is one then I have no doubt that something akin to life exists up there.
    • Don't forget Io - there's plenty of internal heat there!

      Io's surface is molten rock with continuous active volcanos. There is so much geological activity on Io, it's almost impossible to spot craters from foreign bodies. Io's too small to have stored the heat itself, it gets it from the tidal pull of Jupiter's gravity continuously deforming its shape.

      Europa is the next closest moon after Io (about 150% the distance from Jupiter), and has liess mass (roughly 50%) - so it should have less tidal disruption. However, observations from Gallileo have shown that the surface of Europa is changing quite rapidly (APOD pic of Europa changing [nasa.gov]), so there is almost certainly some internal heat there. Europa is almost certainly the best candidate for life in our solar system.

  • DNA? (Score:1)

    by cosmo7 ( 325616 )
    curiosity: If there is bacteria on europa, would it have familiar dna, or a completely different system?
    • If there is life on Europa I'd speculate that it was more likely that it shares a common history with life on earth (and maybe DNA) than that it arose independently.


      It's probably not completely crazy to suggest that biological material could have been carried from Earth to Europa or vice versa (though trying to work out a viable trajectory for volcanic ejecta, say, that takes less than 4 billion years, might be tricky!).


      It seems to me less likely that life would have arisen completely independently in both environments. (If life could have arisen independently on two planets in the solar system I'd expect the universe to be teeming with life and we'd have received a message from them!)

    • Most likely DNA would not be used by a extra-terrestrial life form. The biochemical combinations are too infinite to suggest a similar chance evolution. ature is econommical and I do bet that many concepts / principlas will be similar ( acid/base potentials, carbon / water based, high energy chemical bonds for energy storage, etc). Of course this depends on the fact that the environmental conditions will allow for water to exist. An entirely new concept (non-water baed, etc) is likely - it's just too complex to guess....
  • Can you say "Andromeda Strain"? :)

    BTW, if we do send astronauts and it turns out I do have a valid point (uh oh...), I think they're going to need more than penicillin! Imagine the report back to NASA: "Uh, Houston, we have a problem. Tell Michael Crichton he was right..."

    :)

    • Probably not. All indications are that these bacterium are extremophiles, and that earth's environment may be toxic to them, if they exist at all. There's very little life that can withstand the extreme differences between Europa's environment and much of Earth's environment. Though it is possible they'd have interesting affects near the sulphur vents.
  • Considering the amount of croissants, Gitanes smoke and cappucino found in the atmosphere.
  • There are now plans to explore lakes under Earth's antartic ice sheets (see article below). Its possible that similar lakes exist on Europa, caused by pressure from overlaying ice and/or from a geothermal heat source. Given the presecne of liquid water it is possible that some form of life would develop. http://www.scienceagogo.com/news/20011105201728dat a_trunc_sys.shtml [scienceagogo.com]
  • There very well could be life on Europa. Now they are fairly sure the microfossils on that Mars meteorite were bacteria, due to chemical evidence. So that gives us at least two planets in the solar system in which life is thought to have developed.
    Europa has a very good chance of having life, also. If it indeed does have a liquid ocean, archaebacteria-like organisms may be found around the warm and chemical-rich deep sea vents in it's ocean. I doubt the color is due to bacteria, though. Its probably just salt.
  • A good book on bacteria in extreme environments is John Postgate's The Outer Reaches of Life [dannyreviews.com] (review).

    Danny.

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