Exporting Life with Objects like Borisov, Oumuamua

Amir Siraj and Abraham Loeb, never lacking imagination, suppose the liklihood of a passing rock or comet picking up life from Earth and transporting it Panspermia style throughout the galaxy. It increases dramatically if life is found above 80 km above the Earth's surface. But, when he concludes "we've never detected life above that height,".. that's incorrect. The International Space Station most definitely has life above that height, and should it suffer an untimely demise at the hands of a visiting Interstellar Comet (Borisov) or Rock (Oumuamua)...traces of life would be transported to the far reaches of the galaxy.
SEE:https://arxiv.org/abs/1910.06414


pete

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Originally Posted by trinitree88

The International Space Station most definitely has life above that height, and should it suffer an untimely demise at the hands of a visiting Interstellar Comet (Borisov) or Rock (Oumuamua)...traces of life would be transported to the far reaches of the galaxy.

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At orbital speeds, a collision may in fact sterilize any life aboard.

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Originally Posted by Noclevername

At orbital speeds, a collision may in fact sterilize any life aboard.

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Yep. I've done the calculation for the Barringer crater....cold iron meteorite, warm it up to the melting point, heat of fusion, heat the liquid to boiling iron, heat of vaporization, heat the vapor, ionization energy of the neutral atoms...etc..and there's sufficient kinetic energy for a fireball result. No argument. That would be sterile. The intriguing part is the Allan Hills meteorite from Mars.
Known to be Martian. Made it to Earth. Has those as yet unconfirmed electron microscopic chains in it. As of now, still only possible fossils. So, panspermia remains in the realm of maybe. They have shown exospores to tolerate brief heating to about 700 degrees, and it would require a glancing blow...to pull it off. Agreed not likely, but that's different than impossible.
pete

The difficult part of panspermia isn't getting life into space, it is preserving it long enough to allow a transfer from one planet to another, or one star to another. Any living organism that was carried away on an interstellar comet might wait millions or billions of years before the comet reaches a suitable planet; after that length of time it is unlikely that anything living could survive.

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Originally Posted by eburacum45

The difficult part of panspermia isn't getting life into space, it is preserving it long enough to allow a transfer from one planet to another, or one star to another. Any living organism that was carried away on an interstellar comet might wait millions or billions of years before the comer reaches a suitable planet; after that length of time it is unlikely that anything living could survive.

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And the vast luck of hitting a "suitable" planet for long term survival and reproduction at all.

I wonder what Ralph Waldo Emerson would have thought of these hypothetical microbes. I say that because he has been quoted as saying, "What is a weed? A plant whose virtues have not yet been discovered." Hardiness could be such a virtue. Those weeds are pikers compared with what these microbes would need to be.

Where one permits the sheer numbers of exoplanets throughout the universe as the reason for the existence of life elsewhere as being 'likely', one also then admits that the sheer numbers of object collisions in such a 'living universe', as a viable 'likely' mechanism for overcoming the downside of long transit times (where microbes sustain themselves by remaining dormant).

One would then have to demonstrate the longevity of viable pre-biotic chemstries as exceeding that of dormancy.

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Originally Posted by Selfsim

Where one permits the sheer numbers of exoplanets throughout the universe as the reason for the existence of life elsewhere as being 'likely', one also then admits that the sheer numbers of object collisions in such a 'living universe', as a viable 'likely' mechanism for overcoming the downside of long transit times (where microbes sustain themselves by remaining dormant).

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I didn't read any post in this thread that says that the sheer numbers of exoplanets throughout the universe is the reason for the existence of life elsewhere as being 'likely'. I didn't read anyone say that life was likely.

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Originally Posted by eburacum45

The difficult part of panspermia isn't getting life into space, it is preserving it long enough to allow a transfer from one planet to another, or one star to another. Any living organism that was carried away on an interstellar comet might wait millions or billions of years before the comet reaches a suitable planet; after that length of time it is unlikely that anything living could survive.

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I thought that the really difficult element of the panspermia theory was that it defied Occam's Razor. In other words, believers of panspermia claim as part of their argument that Earth couldn't create life out of nothing so it had to be seeded.

But then, the life that came on Earth through panspermia also had to appear somewhere else in the first place. So if it happened elsewhere, why couldn't it happen on Earth as well? It also neatly avoids the physics of a meteor crash and it's sterilization effect on life.

I'd like to think that both possibilities may be true. If life is reasonably common, then panspermia events might occur on a limited scale throughout the universe. So life might evolve on one planet in a solar system, then spread to one or more planets in that solar system. Similarly life might rarely spread to another, nearby solar system - especially when stars are close together in a cluster. But unless abiogenesis is a very rare event, panspermia probably would be less common than abiogenesis, because panspermia itself is unlikely.

meh, yes: populating mars with 8-legs tardigrades (and waiting for them to evolve into nasty little critters!) seems much more feasible (assuming that they find anything to eat)...

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Originally Posted by Barabino

meh, yes: populating mars with 8-legs tardigrades (and waiting for them to evolve into nasty little critters!) seems much more feasible (assuming that they find anything to eat)...

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Under Mars conditions, they would remain in their suspended animation. Not a good enough environment to revive them.