I have been contemplating the universe..

I have come to a fork in the road for many of my thoughts..

Is the Universe Finite or Infinite

Each choice dictating the direction of further contemplation on any given thought

For example: Finite: If the universe started out from an impossibly hot, impossibly tiny singularity, (such as in the Big Bang Theory), then.. What did that singularity exist in? what was around it, what co-existed with that singularity? how was it considered hot if nothing around it existed with any varying temperature with which to compare?

These examples represent one blade of grass in the entire milky way, as far as how many questions there are with the two-headed fork

But if the Universe is infinite, these questions don't exist and an equally massive list of new ones pop up..

Just curious on your guys' thoughts..

This is an ongoing debate in the physics literature. I'd say there's good reason to think the universe is infinte, but not everyone agrees.

How about both? Finite and Infinite?

If the universe started from a single point then it would have to have a boundry as well as a center.

The idea that it has a boundary is correct, but in the may mass bends space time leads to the conclusion that it may of may or may not be bent into a sphere of sphere like structure, which would mean that through natural propulsion an object would travel in the straightest possible line, in this case around ion a circle, but I guess the only way we'll ever know if weather the universe itself is expanding at or greater than escape velocity.

i remember i watched something about string theories and somehow they began to explain that the universe is just a cosmic bubble on vast dimensional curtain and that these bubbles are constantly forming and popping.

so yes, the universe is finite

My opinion, it is finite, yet ever growing. It can be measured, only to be measured again at a bigger distance.

Here's one to test your noggins...

If the Uniferse is finite, but expanding at the speed of light - there's no way you could EVER perceive the boundary - making it infinite by default.

My high school science teacher used to say something like "the universe is finite, but unlimited". He explained it in a way that made sense but I can't remenber well...

"An intriguing question is whether infinity exists in our physical universe: Are there an infinite number of stars? Does the universe have infinite volume? Does space "go on forever"? This is an important open question of cosmology. Note that the question of being infinite is logically separate from the question of having boundaries. The two-dimensional surface of the Earth, for example, is finite, yet has no edge. By travelling in a straight line one will eventually return to the exact spot one started from. The universe, at least in principle, might have a similar topology; if one travelled in a straight line through the universe perhaps one would eventually revisit one's starting point."
http://en.wikipedia.org/wiki/Infinity

Well it depends on if you believe that predestination exists..
If so then everything that can happen is happening. Has already happened, and will continue to happen forever. Predestination means that every possible outcome of any-thing is has and will happen at the same time and will continually happen somewhere forever.

>>10
Yes, the analogy of the surface of the earth is exactly correct -- The surface of the earth is a finite 2-dimensional surface, but unbounded. General Relativity requires that the universe must have those same characteristics -- and some of the early physicists (there are papers online from them, google "relativity 3-sphere") proved that any qualifying geometry of the universe must necessarily be the "3-sphere". This is like the surface of a sphere, except instead of a sphere in 3 dimensions, you have a sphere in 4 dimensions. The surface of that sphere is 3-dimensional. It has the same properties of the 2-sphere that it is unbounded and finite. It also has some other interesting properties, including that the center of this sphere is entirely arbitrary. Every point can equally be considered the center.

Just like with the familiar 2-sphere, a straight line in any direction will eventually return to its origin, but we will never be able to look out in space with a telescope and see the earth, because the 3-sphere of the universe is expanding faster than the speed of light. As a result, the visible universe is only a small portion of the universe that we will never be able to see beyond. In GR, it can be described exactly like a black hole. A black hole can be described as a region where space itself is getting pulled into the singularity faster than the speed of light, so no information can ever reach us from that region. The area outside the visible universe is mathematically the same -- anything that far out, and that part of space is moving away from our part of space faster than the speed of light.

Why considering universe as infinite makes question about placement and what is outside not important? As it really doesn't matter if space is finite or infinite for this question as we really can't see beyond it, it makes this question more of a philosophical nature.

And even if space is finite and has boundaries, for me there is no "what is beyond the edge" question and not even because we can't reach it (as few people already mentioned). Why? Because beyond edge nothing exists. Absolute nothingness, no black or white space, just nothing. No time, no space, as those exist within edge. Universe is not placed anywhere, as it defines space and placement itself.

But probably it still doesn't have any boundaries anyway but if it is infinite or finite...

Well, what was the starting mass of space? ;)

>>13
What is the start of space?

I like to think the Universe has a finite boundary thats ever growing and a infite mass, it just a theory, with nothing to back it up.I see it as the big bang not as a explosion, more as infite mass of building blocks drifting apart, well not drifting apart , but space stretching and the parts gaining space away from each other, and those parts eventualy creating hydrogen atoms, forming into stars, then galaxys.all at the same time. So the universe is finite only in the sense of what we can observe , but infinite in reality.

You can't say nothing "exists" outside the edge or boundary of the universe because, because you're saying there is actually something that "exists" outside of the universe, which is nothing. So what you're really saying is that nothing is actually something because you're giving it the characteristic of existence. I think an infinite eternal universe is a lot easier to wrap my brain around than a finite one with nothing outside of it.

>>8
Universe would actually have to be expanding at a rate above the speed of light to not collapse under the influence of gravity. This means there is a lot of 'empty space'. But the uncertainty principle makes the existence of empty space impossible. So in this space new matter is created, eventually new galaxies form with new stars and possibly new forms of life.

>>9
Maybe he explained it like a globe or a sphere. It has finite area, but it's unlimited (there's no boundary to the surface of a sphere). Of course the finite but unlimited idea has to be applied to the 4-dimensional space-time construction.
That's the way I like to see the universe, and unlike what I actually think (I'm an agnost), this has as a consequence there is no god necessary to start our universe. Why? Because there is no start of our universe, so nobody could have started it.

There is no way we can measure the amount of mass in our complete universe. We can only roughly measure the amount of mass in the observable universe (which is higher than the actual mass, because we can't observe black matter).
Also to the question of 'beyond the boundary'. This is no question ever to be thought of, because the universe expands faster than the speed of light, so we wouldn't be able to keep up or even get closer to the border than we are at this moment.
To not confuse anybody, it's not because space-time is finite but unlimited, space has to be as well.

I hope I've helped...