MrDarwin

From sciencedaily.com: <a href="http://www.sciencedaily.com/releases/2002/12/021217072401.htm" target="_blank">Microorganism Isolated In Space</a> (the headline is somewhat misleading)

The Lone Ranger

Not too impressive, if you ask me. There are any number of ways that Earthly bacteria can wind up in the atmosphere, and once there, they're small enough that they would remain suspended indefinitely.

One often finds ballooning spiders floating miles above the earth's surface, too, but nobody suggests that they are extraterrestrial in origin.

I don't doubt that comets and asteroids seeded the early Earth with organic material, but I think the hypothesis that Earth was (and is) seeded with living organisms from space is not very well-supported at all.

Cheers,

Michael

thebeave

Even if there were actual living organisms on meteorites that then landed on earth, wouldn't the firey re-entry into the earth's atmosphere destroy them? How exactly could a living bacteria-type lifeform exist for thousands/millions of years on a barren rock in the void of space, anyway?

bluefugue

Could it go into a kind of stasis, to be "reawakened" when the proper environmental conditions were met?

Dark Jedi

Just as a reference to stasis and awakening, look up "Water Bear".

This exists, and shows amazing capability to survive extremes for indefinate periods of time.

Not that it could survive a re-entry, but if you could find a way , it could certainly survive the trip....

<a href="http://www.microscopy-uk.org.uk/mag/artjun00/mmbearp.html" target="_blank">Found a nice site: "The Incredible Water Bear"</a>

Risiko

AFAIK the temperature inside a reasonably sized meteorite doesn't rise much during the short trip through Earth's atmosphere.
Most of the kinetic energy is absorbed by the surrounding air.
Complex organic material (a bacterium for instance) should be able to survive if hiding "below surface".

Edited to add:
But how to remain chemically intact during millions of years of cosmic radiation, I don't know.

[ December 19, 2002: Message edited by: Risiko ]</p>

Boro Nut

Be fair. Micro-organisms by definition are very small. That's what micro means. Space, in contrast, is unfeasibly large. Is it any wonder it feels isolated?

Boro Nut

thebeave

I thought of that too... the microorganism living inside the meteor. But how did it get inside there in the first place? Meteors are largely solid stone or iron as I recall. And aren't the vast majority (if not all) meteorites just remnants from the creation of our own solar system? If that's the case, why do people even entertain the idea that life may have started on a tiny, largely inert rock in orbit around the sun, rather than a huge planet with an abundance of water, an atmosphere, organic chemicals and a favorable climate? The whole concept has seemed ludicrous to me since I first heard it years ago.

If people think the meteor came from outside our solar system (i.e. a renegade from a nearby star system for example?), aren't the odds vanishingly small that it would hit our planet?

Jack the Bodiless

I think the only vaguely plausible variant of this scenario is the "bugs from Mars" theory.

If life evolved on Mars when it still had oceans, chunks blasted into space could have carried microbes to Earth.

...But this isn't likely to happen anymore, because I don't see how the bugs could have survived millions of years of dormancy, either on Mars or inside meteorites.

Shadownought

Does this theory state that bacteria on earth ORIGINALLY came from meteors and such, or just that bacteria DOES come from meteors and such? The phrase "seeded in the past" sounds like it's the former, but it doesn't specifically say.

If it is the former, he's saying that bacteria, although capable of surviving on Earth, somehow didn't come into existence on Earth, and instead had to originate either on ANOTHER planet capable of supporting the same bacteria where they DID come into existence, or else a barren chunk of rock floating in space? I agree, that sounds pretty lame.

As for the latter, I'm gonna need more evidence than bacteria floating up in the air before I buy that.