[HN Gopher] Meteorites give the Moon its thin atmosphere
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       Meteorites give the Moon its thin atmosphere
        
       Author : Brajeshwar
       Score  : 8 points
       Date   : 2024-08-19 12:58 UTC (3 days ago)
        
 (HTM) web link (arstechnica.com)
 (TXT) w3m dump (arstechnica.com)
        
       | lolc wrote:
       | One thing not clear to me after reading the article: Are these
       | "atmospheric" particles in orbit around the moon, or is there
       | enough collisions between them (actual pressure) to keep them
       | afloat? Or both?
        
         | cwillu wrote:
         | According to
         | https://www.ias.ac.in/article/fulltext/jess/114/06/0637-0644,
         | the mean free path of particles in the moon's "atmosphere" is
         | thousands of km.
         | 
         | This makes me think it's probably a combination of suborbital
         | and out-gassing during daylight, with the occasional collision
         | boosting a molecule to orbital or escape velocities. Which
         | technically would be pressure I guess, but not on normal
         | timescales.
        
       | csours wrote:
       | [delayed]
        
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       (page generated 2024-08-22 17:00 UTC)