QUESTION:
How did Jupiter get so many gases?  Did all the gases in space form Jupiter?

ANSWER from Ted Chandon on May 20:
You have the right idea, although you can't say that ALL the gases
in space formed Jupiter since there are other things (including gases) still
there.  

Planets form from the same gas and dust cloud that their star, or 
sun, forms from.  Planets that form close to the star are formed at a high
temperature so things like rock and iron are solid but stuff like water is
too hot to be even a liquid.  Planets that form farther away, like Jupiter
and Saturn, form at a much colder temperature where water is in the form of
ice.  Since there is a lot more water than rock in the universe, the planets
that form farther from the star are a lot bigger than the ones that form in
close to the star.  Of course, if you get too far from the star, the dust
and gas cloud that the star and planets are forming from gets thinner so the
planets can't grow as big there.

You might ask how the Earth got so much water since it is a rocky
planet that formed close to the sun.  A lot of other people wonder the same
thing.  One idea that I've heard is pretty popular is that the Earth formed
first without water and then later after things had cooled off a little,
comets hitting the Earth could have provided the water that we now have.