Earth Life Possibly Could Reach Titan 237
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."
Airborne bacteria? (Score:5, Interesting)
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.
Re:That Would Be A Very Tough Bug (Score:5, Interesting)
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.
Water Bears (Score:4, Interesting)
Was Europa Always Airless? (Score:3, Interesting)
Re:Airborne bacteria? (Score:1, Interesting)
I always wondered if inside Jupiter's atmosphere there are layers with sufficient heat, and low pressure, to be able to support life. IRC, Carl Sagan did some specullation about it, and created an imaginary ecosystem that could exist inside Jupiter's atmosphere.
Just look at our oceans, there are lots of life there, even complex organisms as fish, living at extreme pressures.
Re:Airborne bacteria? (Score:1, Interesting)
Wouldn't that be something if we've evolved from bacteria that was orginally the cause of some cold/illness of life on another planet?
Re:Was Europa Always Airless? (Score:3, Interesting)
Sounds reasonable to me. Earth life at the time may have been better suited to Jovian environments than it is now.
Could be problematic if we ever got there (Score:3, Interesting)
Neat idea...wish it were more probable. (Score:4, Interesting)
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)
>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.Re:Crash differs from explosion to escape velocity (Score:5, Interesting)
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.
Re:Was Europa Always Airless? (Score:3, Interesting)
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.
Mir was a good example... (Score:5, Interesting)
(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.)
Don't Colonise yet! (Score:2, Interesting)
Deliberately contaminating the environments of our neighboring celestial objects with our mutagenic biomatter might be considered an unfriendly greeting by the local populations.
But we'll keep doing it anyway. It seems unlikely that human spacefaring will be found in the long term to be a significant vector for the spread of life -- not because we don't do it but because life has been littering the solar system for much longer than we've been exploring it.
In addition to the rocks that smote the dinosaurs which might have spread life to other planets there are:
The better question is not "does life exist elsewhere?" but rather "if not, why?" We just have to probe around as best we can to get some preliminary results on the first question before we explore the second.
The question I want answered involves the asteroids -- who will be the 49'er to figure out how to capitalize on that unimaginable wealth? The investment is significant, but if you could get a reasonable amount of water, a nuclear power plant and about 50 people to the asteroids, in thirty years you could own everything outside the moon's orbit. Of course at that point closing the deal on the rest of _everything_ would be trivial.
Stupid question about stuff hitting earth (Score:1, Interesting)
Is it just me, or does the idea of meteors kicking stuff *off the earth* not pass the laugh test?
Re:Its life Jim, but not as we know it. (Score:2, Interesting)
So if Titan was lifeless, the lawyers would die. If not, well then poor Titanians.
Re:Mir was a good example... (Score:3, Interesting)
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 conditions of the test, which were obviously very limited, no changes were observed.
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.
Why is deep space "nastier"? It's certainly colder, if that is what you mean. Is the galactic cosmic ray (GCR) intensity really that much different in deep space than it is around Earth? (sure, we see modulation but that does not imply significantly less intensity right?, granted we really don't know). Inside the heliosphere we have not only the GCR problem but we are also, by definition, fairly near to the Sun, I ~ 1/R^2
Why would some little-microbe-dude, partying inside a little rock, many light years from any star have a "nastier" environment than one inside our heliosphere?
No one really knows the lifetime of these "dudes" but (humor me) if it's ~ millions of years then why could they not arrive (in tact) at a distant star? And the obvious question is, why then could our planet not have been populate in a similar scenario?
Re:Stupid question about stuff hitting earth (Score:3, Interesting)
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?
Re:Airborne bacteria? (Score:3, Interesting)
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 the theory is wrong.
But one reason that the theory is appealing to some is that the fossil record seems to show that life appeared on Earth not long after the planet became capable of supporting life. If life originated here, you have only a small amount of time and space in which to get all the chemistry right. Advocates of panspermia would have you believe that the odds of getting it right are low. But if you accept that life might have started elsewhere, that allows more space (other planets, or even dust clouds) and more time (stars older than the Sun) for that origin to occur. The odds of life starting at least once in that larger time and space are much better than the odds of it starting on one specific planet in one specific period. It only has to happen once. After that, by definition, life will spread.
I'm not saying I believe it myself; just trying to explain why some people do. And this simulation doesn't prove that the theory is right, just that it's possible.
Re:Airborne bacteria? (Score:2, Interesting)
Re:Ionizing radiation, et al. (Score:3, Interesting)
You might be interested in D. radiodurans [microbe.org] which can survive 1.5 million rads whereas 500 - 1,000 rads can kill a human. However this item [umr.edu] explains the repair mechanism.