I like to think of the universe as closed, but I'm still wondering what happens if you stick your hand out of the "end" of the universe. Either way, the universe is going to hit a apocalyptic end D:
First of all I personally believe the univerese is not flat because if it was we would be flat, unless by flat you mean something along the lines of a rectangular prism.
I think that the universe is open and constantly expanding until gravity eventually pulls the whole universe in and collapses. when it collapses it will cause another big bang...
I too think that we will never be able to reach the speed of light because we simply cant produce enough energy thus time travel is probably never going to happen
the universe is infinite in the fact that if you were to fly around in a single direction, no matter how fast, that thered be no end. but i think the universe is also round in the way that if you kept going, youd end up where you started, at the same time its endlessly expanding. this is a very touchy subject as everyone has there own opinion, and really none of us are probably right, and the truth about the universe is probably really much more amazing than we can possibly imagine
