According to Einstein's theory of general relativity, gravity bends or warps space-time. this is because the gravitons, or gravity waves, contain no mass and therefore exert their force over large distances with infinite speed. in other words, light from a star that passes by a large body, like our sun, could appear in a place that it is not. the gravity from the sun would bend space time so that even though light may seem to follow a striaght path, it is actually following a curved one. the gravity of large bodies doesnt affect places lightyears away at this magnitude because gravity's force diminishes as it gets farther away from its source. this has led many physicists to believe that if one went in a straight line, they would eventualy end up at the same place after a period of time. this is because all the matter in the universe has warped space time so much, that space time would appear like the earth or sphere. (as if looked through a 2d space) i would agree that at some point in time, all the matter in the universe was very hot and dense. (the big bang) let us go through what i think will happen throughout the expansion of the universe. first, the big bang would take place obviously. next, like it has been found, galaxies that were formed would expand from the point of the big bang. since there is much evidence to say that gravity will not stop this expansion and conclude in an event known as the big crunch, it is logical to say that the universe would continue to excpand forever. however, since the matter in the universe bends space time so much, they would eventually meet either halfway around the universe, or back at were the big bang took place. this wouold result in another big bang. i accept this because it seems that everything that is clear to us is very similar. for example, atoms have a nucleus in which electrons revolve around. the moon revolves around the earth. the earth revolves around the sun along with all of the planets in our solar system. the sun revolves around the center of our galaxy. wouldn't it be safe to say that the galaxies in our universe revolve around the center of the universe. it is very hard to imagine such a thing in 3d space so i will use 2d space for now. galaxies could be represented as electrons and the center of the universe is represented by the nucleus of an atom. this would imply that the universe is finite, but spacetime is infinite. our universe is contained in space time. fire away people!