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dumdedo
Dec6-11, 05:43 AM
I've been searching and trying to find an answer to this. I'm not scholar or physics major. I'm asking for some guidance about this subject.

The big bang theory, leaves me with the impression that atoms can change size.

Is this true?

Can gravitational forces compress, can atoms become smaller?

What regulates an atom's size?

Can adjusting the space/time fabric change the size of an atom?


Thank you for your time. I'm really wondering how all the atoms can fit into the space of a green pea, as computer models suggest.
mathman
Dec6-11, 03:36 PM
As far as I know gravitation does not effect the size of atoms. Size for atoms is a difficult concept, but the simplest way to look at it is in terms of energy. Increasing the energy of an atom means the electrons are in more energetic levels which take up more room.
dumdedo
Dec6-11, 03:43 PM
As far as I know gravitation does not effect the size of atoms. Size for atoms is a difficult concept, but the simplest way to look at it is in terms of energy. Increasing the energy of an atom means the electrons are in more energetic levels which take up more room.

Then forget gravity.

If there is space inside each atom, would it not also have to obey the expansion of space?

http://en.wikipedia.org/wiki/Metric_expansion_of_space

http://upload.wikimedia.org/wikipedia/commons/thumb/a/ac/Raisinbread.gif/200px-Raisinbread.gif
HallsofIvy
Dec6-11, 07:51 PM
Why would you say "The big bang theory leaves me with the impression that atoms can change size"?
dumdedo
Dec6-11, 08:03 PM
Because if expansion of space is true, wouldn't the size atoms be related to the size of the Universe?
phinds
Dec6-11, 08:13 PM
Because if expansion of space is true, wouldn't the size atoms be related to the size of the Universe?

Not at all. The expansion of space has no effect on gravitationally bound objects, such as clusters of galaxies, galaxies, solar systems, planets, you, atoms, etc.
dumdedo
Dec6-11, 08:17 PM
So, space inside each atom is not effected by the inflation of space? Is that space inside an atom special?
phinds
Dec6-11, 08:50 PM
Has nothing to do with space, it's the presence of a force that binds the objects together. For macro objects, it's gravity, for micro objects, it's sub-atomic forces.
dumdedo
Dec6-11, 09:35 PM
Okay. I was just under the impression that if gravity caused macro objects to be pulled towards each other, the galaxies would not be getting farther apart, like they are doing.
DaveC426913
Dec6-11, 09:59 PM
Okay. I was just under the impression that if gravity caused macro objects to be pulled towards each other, the galaxies would not be getting farther apart, like they are doing.

They are getting farther apart precisely in the empty gaps where gravity is too weak to pull them together.
dumdedo
Dec7-11, 12:27 AM
They are getting farther apart precisely in the empty gaps where gravity is too weak to pull them together.

http://en.wikipedia.org/wiki/Metric_expansion_of_space

The universe isn't slowing down, either.
phinds
Dec7-11, 06:20 AM
http://en.wikipedia.org/wiki/Metric_expansion_of_space

The universe isn't slowing down, either.

That is correct. Do you have a question about that?