Earth Microbes Could Be Populating The Solar System

New Studies Show Microbial Hitchikers Can Survive Millions of Years in Outer Space

In a unique experiment on a galactic scale, millions of bacterial spores have been purposely exposed to space, to see how solar radiation affects them and the results supported the idea that not only could life have arrived on Earth on meteorites, but that considerable material has flowed between planets.

Closer to home, scientists have analyzed aerial dust samples collected by Charles Darwin and confirmed that microbes can travel across continents without the need for planes or trains - rather bacteria and fungi hitch-hike by attaching to dust particles. Their results clearly show that diverse microbes, including ascomycetes, and eubacteria can live for centuries and survive intercontinental travel.

In a paper published in Environmental Microbiology, Dr. Anna Gorbushina (Carl-von-Ossietzky University, Oldenburg, Germany), Professor William Broughton (University of Geneva, Switzerland) and their colleagues analyzed dust samples collected by Charles Darwin and others almost 200 years ago...

...In earlier experiments, Horneck and her colleagues used the Russian Foton satellite to expose 50 million unprotected spores of the bacterium Bacillus Subtilis outside the satellite. UV radiation from the Sun killed nearly all of the spores, and did so even when the spores were confined under quartz.

To test if meteorites might protect bacteria on their journey through space, Horneck and her colleagues mixed samples of 50 million spores with particles of clay, red sandstone, Martian meteorite, or simulated Martian soil and made small lumps a centimeter in diameter. Between 10,000 and 100,000 spores of the original 50 million survived and when mixed with red sandstone, nearly all survived, suggesting that even meteorites a centimeter in diameter can carry life from one planet to another, if they completed the journey within a few years. In a rock a meter across, bacteria could probably survive for millions of years.

In a separate experiment, another team ran computer models of giant impacts like Chicxulub. In the simulations, millions of large boulders were ejected from the earth. About 30 boulders from each Earth impact even reached Titan, and they entered Titan’s atmosphere slower than most meteors hit Earth’s atmosphere. Big rocks from Earth have no doubt reached Enceladus, as well....

See the research paper Microbial Rock Inhabitants Survive Hypervelocity Impacts on Mars-like Host Planets: First Phase of Lithopanspermia Experimentally Tested for more details.



[edit on 19/5/08 by Rapacity]

Not an entirely new topic (hope this one hasn't been posted before) but the last paragraph is quite interesting where it states that boulders from Earth have been ejected as far as other planets and their moons. Coupled with the knowledge that microbes can survive a journey on a rock through space and knowing that life is found nearly everywhere we look on Earth (including some that survive by eating radioactive rock), I imagine it is very likely that life from Earth would survive in any new, alien environment.

To turn the tables on the "Did life on Earth originate in outerspace" idea, could life in space have originated on Earth?

We know that throughout Earth's existence it has been bombarded with large space rocks and has had a lot of volcanic activity enough for tons of life carrying material to have been ejected into space. How much would have been pushed out when the moon was formed? Is it such a far stretch of imagination to assume that after billions of years of evolution on a far-off planet or moon, that some form of animal, plant or "undiscovered type of" life might have developed?

Obviously, we still need to deal with the question of how did life form on Earth but it had to begin somewhere, didn't it? I know other systems have existed much longer than ours but if life is such a unique and unlikely thing then I suppose it might have occurred once in the Universe; and if it did, might it have been from here?

Acording to NASA scientists I chatted with online, we send unsterilized things into space. I'm sure our microbes are scattered all over the solar system. This is one of our mandates as living beings, to spread.

reply to post by earthman4


Couldn't agree more with you that life's mandate is to spread.

I'll take your word for it that we send unsterilized materials into space however, I've read before that we sterilize space going materials before we send them to other planets, moons, asteroids but (and this is me saying this) we can only look for sterilization from life forms we know about. I think prions are a fairly recent discovery. It isn't likely we would have unwittingly sent prions into space but it is possible we've sent something.

Were all the early space going materials sterilized? I recall their being some contention over the procedure used - send it out and space will kill anything on it.

Anyway, I think that if Earth originating life has adapted to life on another rock, considering the extremes of the case, it could well have evolved further than it has here.

Anyone who says: If it has then where is it? Well, were you on Titan or Io and had developed technologically, would you stay put or would you find somewhere more homely?

[edit on 19/5/08 by Rapacity]

[edit on 19/5/08 by Rapacity]