# The Shape of the Universe

## Main Question or Discussion Point

I know how to figure out the shape of the universe. There are three shapes the universe could be. Spherical, flat, or hyperbolic. If it it spherical the universe will someday colapse in on itself. It is not expanding fast enough to overcome gravity. It is slowing down if it is a sphere. If the univers is flat then it will expand forever just barely. It will stay a constant speed. If the universe is hyperbolic it will expand infinitly with no problem. It will increase in speed infinitly. Now picture a dagra of the universe. The point in which the universe was condesed befor the bigbang in the middle. We are on the left. Another galaxy is on the right. any shape the universe is, there would be a massive redshift. Now there is another galaxy farther to the left then us. If the universe was spherical and decelerating we would see a blueshift. If it was flat we wuld see no shift and if the universe was hyperbolic we would see a red shift. It would be the same if there was a galaxy in between us and the point of the bigbang. So that means if we can find any blueshifts, we live in a spherical universe. If we find galaxie farter away the say Andromeda that have no shift then we live in a flat universe. And finally If we only can find redshifts there is a good possibility that we live in a hyperbolic universe.

marcus
Gold Member
Dearly Missed
There are three shapes the universe could be. Spherical, flat, or hyperbolic. If it it spherical the universe will someday colapse in on itself. It is not expanding fast enough to overcome gravity. It is slowing down if it is a sphere.
No.
That is what people would often say before 1998.
You still see that on some websites.
The current model that cosmologists use can have closed (hyperspherical) space and still keep expanding forever.

If the univers is flat then it will expand forever just barely. It will stay a constant speed.
No. You need to study some up-to-date material.
The current model that cosmologists use (after 1998) has the possibility to be spatially flat and expand at an accelerating rate.
In fact this is the most common version of the model---spatial flatness and accelerating expansion.

If the universe was spherical and decelerating we would see a blueshift. If it was flat we wuld see no shift and if the universe was hyperbolic we would see a red shift. It would be the same if there was a galaxy in between us and the point of the bigbang. So that means if we can find any blueshifts, we live in a spherical universe. If we find galaxie farter away the say Andromeda that have no shift then we live in a flat universe.
Unfortunately this does not make sense. The reality is not as simple as you think it is.
Maybe someone here can suggest an online book for you to read, to learn the basics.

Chalnoth
Perhaps more to the point, barring some extremely unlikely set of circumstances, the way our universe will expand from here on out will make it so that the effect of curvature diminishes with time, so that it will become asymptotically flatter and flatter.