Something to boggle your mind , open and closed universe, please read?

Question

ive been reading about how the universe was created Most famously known is the big bang which shows that somehting occured and all matter was spit in a big explosion and the universe is expanding planets are moving farther away from each other at high speeds ( similar to rasian bread , As the bread is baking and is expanding all the raisins are moving farther away from each other seeming as if each individual raisin or (planet , glaxie) is the in the center) now a couple theories ive read state that there are both Open and closed universe theories , Closed being where the universe will expand to a specific point and gravity will counter act or draw all matter back into a fixed point ( like inflating and di-inflating a ballon) problem is that there isnt sufficient enough gravity to draw everything back in so an OPen theory indicates it will expand for ever and become nothing , a start and an end , Now i was thinkin what if there is a combination of both what if we are in an ever expanding universe or ( ever expanding ballon) which is itself inside a contracting universe or ( contrating ballon) , to get ur head around this what if were inside ballon A which is expanding , but ballon A is Inside Ballon B which is contracting? if the force of ballon B is greater then A ultimatly we would ourselves contract back to a fixed point which elliminates the need for gravity to draw all matter back into a kind of Dense flaming ball

Answer 1

This doesn't make sense. One universe can't be inside another one.

Answer 2

An idea is not a theory until it can be tested.  Since we can only see balloon A, how can we test the idea that there is a balloon B and that it might be behaving in a way that affects balloon A?  We are not even sure we understand everything about balloon A, yet.

The raisin bread example is an analogy:  it explains why the distances increase between objects, yet the objects themselves are NOT moving in relation to their immediate neighborhood.

There was no explosion.  The Big Bang was simply the beginning of expansion (and it is still ongoing).  The Big Bang theory explains what happens to a universe that begins in a state of very high temperature (energy density), and cools as space expands.  If the Big Bang had been an explosion, the raisins would move through the dough, not with the dough.

The Open (or Closed) Universe "theories" -- they are in fact mathematical "conditions" that can be tested -- depend directly on gravity.  Either gravity is sufficient to stop expansion (closed universe) or it is not (open universe).  This can be tested: we can try to see if expansion is slowing down or not (it is not) or we can try to measure the average density of matter and calculate the resulting gravity (it is not sufficient to close the universe).  Of course, the test itself is not easy (the universe is so big and we can sample so little of it at a time).

The entire idea of "Open or Closed" is based on the fact that this universe is the only thing that exists: there is no outside force that can act on it.  To continue your analogy:  Balloon A will stop expanding because something inside balloon A will cause it to stop.

What you propose brings in an effect that could come from outside (balloon B) what we presently call the universe (balloon A).  This is certainly not the first time scientists would consider outside influences (M-theory, string theory, multi-verse...).  

The idea of something outside our universe acting on our universe is very difficult to test (and is not required by observations... yet).  However, once we begin considering possible effects from the outside, we have to stop thinking about Open and Closed in the traditional way.

You can't really mix the two concepts together (Open/Close vs outside effect).

At least, not yet... But who knows, you may become the one to find a way to mix them (it will take time).  Find a way to test for Balloon B.

Answer 3

A universe within a universe? I don't think so. I can visualize other universes being possible, but the notion of one being inside the boundaries of another defies all logic in physics.  

Answer 4

Well, the problem with your theory is the double-universe.  Matter can't exist and remain the same in all parts of one universe, and be affected by events or constraints in another.  

By definition, a "Universe" means everything.  So, if there's another "universe" out there, we have no way of detecting, experiencing, or feeling it - it could live & die in the same virtual "space" as us, and we'd be completely unaware.  

Answer 5

There is, of course, no reason to dismiss your concept of the universe, more than there is of the Big Freeze (ever expanding universe) or Big Crunch (collapsing universe).

But I think that your analogy of the balloons is wrong. You see, the Big Bang was not an 'explosion' and our universe has no boundary that can be contained in another one.

That doesn't mean that the universe can't be expanding and contracting at the same time - as you suggest. I simply think that you must think in another way and perhaps read a bit more about relativity.

You see, relativity tells us that the universe can only be observed from an observer's frame of reference in space, time and inertia. When we see all galaxies moving away from us, it doesn't mean that we are the center of the universe; it simply means that - wherever you are in the universe - you can only observe it as if you were at its center.

Likewise, when we observe the Cosmic Microwave Background, the left-over of the Big Bang, we see it coming from all directions in the sky. This is because we see the Big Bang not as a point in space but a sphere around us. Strange, isn't it? That's where Relativity is fascinating.

Maybe there is a place for your 'expanding yet contracting' model. But you should elaborate it more in consideration to what we already know and observe. Relativity and Quantum are good points to start learning more.