Re: What is the reason that there is there no oxygen in space?

Actually, there is oxygen in space, however, the majority of it has already 
been captured gravitationally by stars, planets, or other celestial bodies.  
So space is *almost* a perfect vacuum, but gas and dust particles do float 
around out there.  These particles are referred to as the interstellar 
medium by astronomers.  

According to Thomas Arny's "Explorations: An Introduction to Astronomy," if 
we were to compare the amount of gas in interstellar space to the air we 
breathe, it would be like "one marble in a box 5 miles on a side compared 
to the same box filled completely with marbles."  So needless to say, there 
isn't very much oxygen in outer space, but there is some.  And the reason 
there isn't more is simply that the gravity of all the other various 
celestial objects out there, including galaxies, has captured most of the 
gas and dust.

For further reading, check out Thomas Arny's "Explorations: An Introduction 
to Astronomy" or, for a more in-depth look, "Fundamental Astronomy" by 
H.Kartunen, P.Kroger, H.Oja, M.Poutanen, and K.J.Donner.