Is the Universe symmetrical? I know it's contantly expanding, but are all sides expanding at the same rate?

The universe does not expand from the sides.

It is expanding from every point within the universe, therefore the sides must be expanding at the same rate all around.

I hope this helps you picture it a little better :)

Those regions of the universe are unobservable.

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The "observable universe," Sweitzer explained, "is the one astrophysicists generally talk about because it's the one open to empirical measurements. In fact it's the only one we can or ever will be able to talk with any certainty about."

He goes on to explain that "universe" (sans the word "observable") is a larger concept that scientists think "conforms to our laws of physics and all the assumptions that go with them." Comprehending this universe, Sweitzer said, "requires a leap of faith into unobservable realms."

James Sweitzer, director of astrophysics education at the American Museum of Natural History's Rose Center for Earth and Space.


Excerpt

Meaning of "universe"

Both popular and professional research articles in cosmology often use the term "universe" to refer to the observable universe. The reason for this usage is that only observable phenomena are scientifically relevant. Since unobservable phenomena have no perceptible effects, physicists argue that they "causally do not exist". Since unobservable parts of the universe cannot be measured, hypotheses about them are not testable, and thus inappropriate for a scientific theory.

http://en.wikipedia.org/wiki/Fine-tuned_universe

http://hubblesite.org/reference_desk...&cat=cosmology