Is space infinite in all directions, finite and bounded, or finite yet unbounded?

Question

And how can we possibly tell if it is any of those?

Answer 1

The prevailing scientific opinion is finite but unbounded, like the surface of the Earth; finite area but no edge. And the reason is the same. Earth's 2 dimensional surface is curved in the 3rd dimension. 3-D space is supposed to be curved in 4-D hyper space, or some higher dimension that we cannot directly detect. To detect the curvature, see if the angles of a triangle add up to 180 degrees or not. A small triangle will, but if the triangle is large compared to the size of the curved surface, the angles will add up to more than 180 degrees. You would need a triangle billions of light years on a side to do that for the universe though. But they can see that far with telescopes now.

Answer 2

A finite but unbounded surface is like the surface of a ball. While it has a certain, specific, well-defined area it has no edges since it curves back onto itself. The surface of the ball is finite but unbounded. An infinite but bounded object can be made by taking an infinite, unbounded plane (for example) and cutting it along some line. There is still an infinite area of plane left, but it ends at a certain line, so it's infinite but bounded.

Answer 3

You just described the three possibilities and no one can tell which is correct. That depends on the ammount of matter in the universe today and it's size, known as omega. If omega is more then 1, the universe is finite and bounded, if it's less then 1 it's infinite, if it's 1 exactly it's finite yet unbounded.
Nobody knows the exact value of omega. Recent studies indicate it might be very close (but still below)1.

Answer 4

There is a lot of debate on this subject. Many believe that it is infinite and unbounded. There are four models of what the universe may be: 1) a recollapsing universe where the universe will eventually begin to collapse and after a period of expanding begin to shrink until it is destroyed. 2)a critical universe. The universe will never collapse but will expand more slowly as time progresses. 3) Coasting universe. The universe continues to expand at a fixed rate, never stopping. and 4) an accelerating universe in which the rate of expansion accelerates.

all four models are based on the balance between gravity (slows expansion) and dark energy (accelerates expansion).

Answer 5

Infinite in all directions. Because i don't know what's the outside finite yet unbounded.

Answer 6

I beleive that the current theory is Finite but unbounded. The ever expandonmg universe if you will also we can tell that the universe is still expanding by timing the light from pulsars.

Answer 7

Infinite In All Directions

Answer 8

I believe space (our Universe) to be finite and bounded but it is expanding into something that is infinite in size and has no boundaries.

Answer 9

Define space. Is it only places which contain matter, or is it anywhere you could go, given enough time and energy, etc?

My guess is it's unbounded if you mean the second.

Answer 10

spacetime is regarded as being finite yet it no edge and no center (boundaryless). it may be something like the two-dimensional surface of a sphere. also, nothing inside or outside the sphere exists for the surface, and nothing exists outside spacetime.

http://universeadventure.org/
http://map.gsfc.nasa.gov/m_uni.html