I am not a cosmologist and this whole space-time thing seems somewhat suspect. As I understand it, the universe is like the surface of a balloon that is increasing in size; so there is no “center” per se.
Here’s my question:
If I pick a direction and go very very fast, will I end up where I start from (assuming I am traveling instantaneously). In other words, if I point, no matter which direction, am I always pointing at the back of my head?
Everyone used to think so, but the trend is pointing to an open model. No one is QUITE sure yet. I like the raisin bread model.
You’re probably sick of hearing answers like this (heck, physicists aren’t exactly wild over them, either), but we’ll hopefully know very soon. There’s a mission in the works called MAP (Microwave Anisotropy Probe) that’ll basically be a rehash of the COBE satellite, but to much better resolution, and it’s believed that it’ll be able to pin down most of the cosmological parameters to a high degree of accuracy.
Even if the Univese is flat, as currently seems likely, there’s still the possibility that you could circumnavigate it if it’s not simply connected-- Think of an Asteroids screen, where you can fly off one side of the screen and onto the other side, even though the screen is flat. If the characteristic size is small enough, MAP’ll also be able to detect evidence for that, if that’s actually the case.
I still stubbornly cling to the idea that when you reach the edge of the universe you just magically pop clear across to the other end, heading the same direction and without missing a beat. Like a self-sustaining reality bubble.
I think I might have played to much “Asteriods” as a kid.
Also note that in such a Universe, you can’t tell where the edges are, just that you eventually get back to where you came from. As Inky- says, you wouldn’t miss a beat. It’s not really magical at all; just imagine the Universe being bent around into a cylindar or higher-dimensional equivalent.
So the universe may be a balloon, or it may be a cylinder. I’m waiting on the theory that it’s shaped like one of those stuffed pink elephants you win at a carnival.
oh the pink elephant theory went out years ago!
the trick is to realize that space can be curved. we perceive that curve as gravity, but actually, 3D space is bends in the presence of matter.