Earth Life Possibly Could Reach Titan

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."

Comments

Airborne bacteria?

[Bahumat]

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.

Re:That Would Be A Very Tough Bug

[LiquidCoooled]

How about this:

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

[7Ghent]

Tartigrades, otherwise known as Water Bears might survive such a journey. They're the cutest microscopic animals ever!

Neat idea...wish it were more probable.

[posterlogo]

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

[Kozar_The_Malignant]

>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

[Ungrounded Lightning]

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.

Mir was a good example...

[jd]

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.)