Recent content by Alberto87

Ah ok, but it only wraps back in one direction, the second direction cannot, am I right? It´s not possible for a flat space to be finite and unlimited, isn´t it? Is the torus a flat space time?

how can a flat space wrap back on itself?

But will the observer know if he was at rest (to the spacetime itsef) or he can just know that he was moving slower than the other observer?

thanks a lot for all your answers, I definitely have a more clear idea on this matter. Ok, I understand the difference I had the wrong idea that masses only curved the space-time locally and not globally and that the global shape of the universe was independent from the energy inside. That's...

Thank you very much for your reply Yes that´s what I meant, I meant that everything within the universe is moving and at rest at the same time. I didn´t express myself properly Unfortunately I don´t have enough knowledge on the matter to understand this. Do you mean that a fixed curvature of...

Hi my name is Alberto, I´m italian engineer who is very interested in physics and wants to learn as much as possible about relativity, quantum mechanics, quantum gravity, cosmology and so on.

Hi I´ve got some question about this paradox (and the whole relativity theory) too but first of all I want to apologize for my poor english. If there's one thing I've understood (reading here and there on the web) it is that it is impossible to determine who is at rest and who is in motion. An...