Recent content by Imax

Space time is intimately related to the Big Bang. Don’t think of the BB as an explosion into infinite space. The BB caused inflation in space and time.

When you say an Infinite Time's Arrow is Impossible, are you saying that time can’t be an independent variable and can’t range from – infinity to + infinity?

Anisotropies from a steady state?

Space-time is either infinite or finite. If it’s finite, then it could be expressed as a compact manifold. A compact manifold can have closed space-like geodesics. Take a string, and put your foot on one end. Make a loop, as big as you can, and pull in the string with your hands. You’ve...

I’m just musing about the possibility of having a space-time manifold that can allow both closed space-like and closed time-like curves. No. That’s why I started this tread. Probably not. Current models of our Universe can allow for the possibility of closed space-like curve. I can’t...

As I see it, if you allow time curvatures, then it could negate our understanding on the age of our Universe (i.e. about 13.7 billion years). It could be much older.

There are probably many different ideas of what you could mean by a Universe that is flat, round, finite, infinite, etc. My personal preference is to look at the possibility of closed space like curves. If you travel long enough in a straight line in one direction (i.e. traveling along a space...

We seem to live in a compact Universe, with the potential for curvatures in both space and time. By time curvature, I mean to say that two clocks are no longer synchronized. I can’t work out the math :)

I can’t see time dilation predicted by special relativity in general relativity. How does GR explain time dilation?

Space-time can have a curvature, which implies that time may also have a curvature. I'm still struggling with this idea, but if you start out with two synchronized clocks and after doing something, those clocks are no longer synchronized, then it could be that time has a curvature. Another...

Can the twin paradox provide us with insight into time curvature? If my twin boards a ship that can travel near the speed of light, special relativity says that on arrival back on Earth, my twin should be younger that I am. Has my twin experienced a time curvature?

Chronos, that's an excellent synopsis on measuring space curvature.

If there were such a star, then it would be difficult to observe its light. It would be difficult, if not impossible, to say that such a star exist. One way of looking at black holes is that they form island universes, separated in space-time from our universe. Another way of asking your...

Yes, the topology of our universe can help us understand our origin. Big problem is to understand that topology (i.e. finite in space and time, or infinite in both?)

If the universe is infinite in space (i.e. Euclidian in all directions), then maybe > 45 Gly. If space is compact and behaves like a 3D analogue of a 2D balloon surface, then it is unlikely that Earth or any other point in space could be at the center; the Universe would look homogeneous and...