Re: is the universe a large atom?

Jason,

You are right; there are some rough parallels between an atom
and the solar system (but note: the solar system is not the whole universe!).

(Size of the Sun)/(Sun-Jupiter distance) ~= .001
(Size of nucleus)/(average electron orbit size) ~= .00001

(Mass of Sun)/(Mass of Jupiter) =~1000
(Mass of proton)/(Mass of electron) =~1800

But there are a lot of differences between atoms and solar systems too.
For example, solar systems and the planets in them are held together by 
gravity, which is always an attractive force. Atoms have several forces
involved: the electromagnetic force (which can be attractive or repulsive)
and the strong nuclear force (attractive), but NOT gravity. This means that
the behviour of atoms is more complex and thus harder to predict.

Atoms also show the effects of quantum mechanics, the randomness that is built
into matter on the smallest scales. This means that electron orbits are not
the simple circles that you see in textbooks; the orbits are really funny-shaped
`clouds' of probability, not like solar system orbits at all.

I agree that it's neat that we can feel part of the universe, and it's great
that you (a part of the universe) are busy thinking about it. Keep it up.

Pauline