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Why does an asteroid have to hit the earth? Life is constantly being shed from the upper atmosphere into space right now. As we travel through space we leave

Why does an asteroid have to hit the earth? Life is constantly being shed from the upper atmosphere into space right now. As we travel through space we leave a plume of life behind us. Certainly almost none of it survives, but almost isn’t none, and a lot of life spreads as hardened spores that can withstand extreme conditions until more favorable conditions present and they “wake up.”

crazygringo 3y ago
> Life is constantly being shed from the upper atmosphere into space right now. As we travel through space we leave a plume of life behind us. Can you point to any source for that? I've never heard of such a thing and can't find anything from a quick online search supporting that idea. Everything I read is that gravity will pull back any bacteria that get to the outer edges of the atmosphere, which makes sense because they'd need to have some force stronger than gravity to escape. What information can you point to that supports the idea that we leave a "plume of life behind us"? I think the idea behind an asteroid is that only something with that level of force could eject bacteria that could overcome the Earth's gravity to escape. Edit: atmospheric escape [1] is a well-known phenomenon, but that's exclusively about gases, at the molecular level. It doesn't mention anything about bacteria, which are of course massive in comparison -- the factors that can cause a single atom or molecule to gain enough energy to escape gravity don't apply to things the size of bacteria. [1] https://en.wikipedia.org/wiki/Atmospheric_escape https://en.wikipedia.org/wiki/Atmospheric_escape
- londons_explore 3y ago
  I suspect the conclusion here depends entirely on upper atmosphere winds which I don't think are well studied.
  - lupire 3y ago
    Upper atmosphere winds are well within the Earth's gravity well. Relative to the center of the Earth (average gravity) , the atmosphere ends approximately at sea level. Small particles aren't escaping based on their own velocity from random collisions. Maybe from interplanetary scraft like Voyager.
- JumpCrisscross 3y ago
  > that's exclusively about gases, at the molecular level Impact erosion seems like it would have enough energy to eject microbes from the atmosphere given the amount of life in the troposphere [1]. [1] https://nautil.us/the-surprising-importance-of-stratospheric-life-235954/ https://nautil.us/the-surprising-importance-of-stratospheric...
- londons_explore 3y ago
  The chance of a particle escaping depends on its mass. That's why helium escapes pretty fast. The other gas molecules still escape, but far far slower. The Maxwell Boltzmann distribution applies. Something like a virus is far far heavier again, so the rate of escape would be miniscule. Not sure if it's small enough to have never happened across the surface of earth though.
bongodongobob 3y ago
Nonsense. How are microbes exceeding Earth's escape velocity?
- cncovyvysi 3y ago
  Solar wind? (Genuine question)

crazygringo 3y ago

> Life is constantly being shed from the upper atmosphere into space right now. As we travel through space we leave a plume of life behind us. Can you point to any source for that? I've never heard of such a thing and can't find anything from a quick online search supporting that idea. Everything I read is that gravity will pull back any bacteria that get to the outer edges of the atmosphere, which makes sense because they'd need to have some force stronger than gravity to escape. What information can you point to that supports the idea that we leave a "plume of life behind us"? I think the idea behind an asteroid is that only something with that level of force could eject bacteria that could overcome the Earth's gravity to escape. Edit: atmospheric escape [1] is a well-known phenomenon, but that's exclusively about gases, at the molecular level. It doesn't mention anything about bacteria, which are of course massive in comparison -- the factors that can cause a single atom or molecule to gain enough energy to escape gravity don't apply to things the size of bacteria. [1] https://en.wikipedia.org/wiki/Atmospheric_escape https://en.wikipedia.org/wiki/Atmospheric_escape

londons_explore 3y ago
I suspect the conclusion here depends entirely on upper atmosphere winds which I don't think are well studied.
- lupire 3y ago
  Upper atmosphere winds are well within the Earth's gravity well. Relative to the center of the Earth (average gravity) , the atmosphere ends approximately at sea level. Small particles aren't escaping based on their own velocity from random collisions. Maybe from interplanetary scraft like Voyager.
JumpCrisscross 3y ago
> that's exclusively about gases, at the molecular level Impact erosion seems like it would have enough energy to eject microbes from the atmosphere given the amount of life in the troposphere [1]. [1] https://nautil.us/the-surprising-importance-of-stratospheric-life-235954/ https://nautil.us/the-surprising-importance-of-stratospheric...
londons_explore 3y ago
The chance of a particle escaping depends on its mass. That's why helium escapes pretty fast. The other gas molecules still escape, but far far slower. The Maxwell Boltzmann distribution applies. Something like a virus is far far heavier again, so the rate of escape would be miniscule. Not sure if it's small enough to have never happened across the surface of earth though.

bongodongobob 3y ago

Nonsense. How are microbes exceeding Earth's escape velocity?

cncovyvysi 3y ago
Solar wind? (Genuine question)