What happens to particles that escape the atmosphere of planets? (not just earth).

Do they eventually form a uniform distribution of particles overtime? Do they inevitably to fall into the gravitational pull of other entities? Do a lot escape the solar system? Do they just orbit the host planet?

I've heard of using ramjets to capture interstellar particles, though not particularly feasible, so there seems to be some dispersion of particles in the universe outside of celestial bodies.

Additionally the answer here to a related question seems to indicate the leftovers from ion drives can be picked back up by earth quite feasibly, and presumably particles ejected due to just barely leaving escape velocity would be travelling much slower.

  • $\begingroup$ first of all you tell me . from where particles gets escape velocity?I think it will be happen when suddenly earth stop rotation $\endgroup$ Sep 26, 2019 at 8:26

1 Answer 1


If by "particles", you mean atoms and similar size things, it's not really just about escape velocity.

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(From WikiCommons)

Once the atoms get more than a half-dozen or so radii away from Earth, they're directly in the solar wind: Atoms out there have mean free paths that are short enough that they collide, come to equilibrium, and move outward with the solar wind.

Inside that, both gravity and (in some cases) magnetism generally binds atoms and charged particles. Slowly some, particularly the lightest ones, will pick up enough energy and momentum to reach the solar wind and be blown away.

  • $\begingroup$ How do we know if this is right or wrong? Can you support "Atoms out there have mean free paths that are short enough that..." somehow? Also I think you need to make it clearer that only charged atoms and particles are affected by the magnetic field directly. The uncharged ones need to have physical collisions to be affected. $\endgroup$
    – uhoh
    Sep 26, 2019 at 15:30
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    $\begingroup$ Sorry, thought that was in the "everybody knows" category. It is called the solar wind, after all, not the solar ejection of non-interacting ballistic trajectories. It's got a well-defined pressure and temperature because of interactions. Will find and add more detail when I get a bigger screen. $\endgroup$ Sep 26, 2019 at 15:38
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    $\begingroup$ Answer that's about half related: space.stackexchange.com/questions/24271/… $\endgroup$ Sep 26, 2019 at 15:40
  • $\begingroup$ Right, so particles get blown away, but where do they end up afterwards? $\endgroup$
    – Krupip
    Sep 26, 2019 at 18:09
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    $\begingroup$ The solar wind captures them and carries them out to the heliopause where they stagnate and (mostly) recirculate. In other words, some stay generally in the solar system and some escape through the heliopause shock. And before you ask: the ones that escape through the heliopause are part of the interstellar medium. Most of that is contained within the galactic envelope, inside the shock separating the galaxy from the inter galactic medium, but a small fraction can escape into that... $\endgroup$ Sep 26, 2019 at 18:50

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