I've read that some plant and tree seeds can be cryogenically preserved for years, if not decades. However, I've not read of anyone considering the following theory: Could it be possible that our diverse plant life here was a result of asteroids skimming or impacting Earth-like planets and carrying/depositing their plant seeds on our Earth? If it's possible for seeds to be carried on asteroids and survive the deep cold of space, then the "seeds of life" on our planet are not just microbial.


closed as off-topic by Organic Marble, Brian Tompsett - 汤莱恩, DarkDust, Nathan Tuggy, Mark Omo May 7 '18 at 18:26

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  • "This question is about other space sciences (physics, weather, astronomy, etc), and does not directly pertain to space exploration as outlined in the help center." – Organic Marble, Brian Tompsett - 汤莱恩, DarkDust, Nathan Tuggy, Mark Omo
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    $\begingroup$ Welcome! You can read about the long history of this theory here. en.wikipedia.org/wiki/Panspermia It's a fascinating topic but not related to space exploration except tangentially. $\endgroup$ – Organic Marble May 7 '18 at 13:12
  • $\begingroup$ Thank you for the reference Organic Marble! Good to know! $\endgroup$ – Richard Louie May 7 '18 at 13:47
  • $\begingroup$ It may be a question suitable for Astronomy.SE, though. $\endgroup$ – DarkDust May 7 '18 at 14:25
  • $\begingroup$ It would require that there are seeds existing on other planets, that these seeds would survive the tremendous heat of an asteroid impact and entry into Earth's atmosphere. Space is deep cold only far away from the Sun, but not near Earth. Seeds should not be destroyed by intense UV light and by out gasing in the vacuum of space. The probability is very, very low. $\endgroup$ – Uwe May 7 '18 at 15:59

In fact some seeds have been viable after tens of thousands of years. Which is pretty close to how long the fastest object to leave our solar system would take to get to the nearest star. Of course it isn't headed that way, and it never came close enough to Earth for anything to transfer, but timing doesn't certainly rule out this idea.

Additionally some algae and other plants have been tested to survive some time in space, though obviously not thousands of years. So the hazards of space also do not yet rule out plants surviving the trip.

But the mainstream view is that the diversity of life is due to local biological effects like evolution, and panspermia of any kind is only an occasional influence at most.

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    $\begingroup$ I'd also add that such seeds should not just survive to space but also to the extremely high temperature of the entry in our atmosphere and the effect of the impact... $\endgroup$ – Adriano Repetti May 8 '18 at 6:52

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