Why can nothing travel faster than the speed of light and what is hyperspace?
Einstein theorized that light speed was the speed limit of the universe. We are still unable with our current technology to prove him right or wrong.
The way the universe works, nothing material (mass or energy) can travel faster than light. There's no "why" for that, it's just the way things are.
Hyperspace is a made-up pretend thing for comic books.
As I understand it, when an object approaches the speed of light the electromagnetic hooks that bind atoms together to make solids become undone.
Our galexies are picking up speed as time goes on. Someday they'll approach the speed of light and the electromagnetic hooks of everything there is will come undone. Astrophysicist say that will be the end.
That doesn't seem a very befitting end to such magnifice and grandur. So scientist wonder and guess. Perhaps there is a Great Retraction, is one theory proposed. That is where the atoms reverse themselves and slam together at some finite point that ignites another big bang. In this view there never was a beginning or an end. This has been going on forever.
The Great Retraction is also called the Big Crunch.