Sunshine

My understanding is that solar wind has a greater effect on
atoms, molecules, and small dust particles than light pressure
has, but light pressure has a greater effect than solar wind
on larger particles and objects.  Why the difference?
 
How do light pressure and the pressure exerted by solar wind
compare at different distances from the Sun?
 
How large does an asteroid (iron or dense chondrite) have to
be in order to fall into the Sun rather than be completely
vaporized by the Sun's heat and blown away by solar wind?
 
  -- Jeff, in Minneapolis
 
Subtract 1 from my e-mail address above for my real address.
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