0
votes
0answers
35 views

Why is it theoretically impossible to travel back through time? [duplicate]

I know scientist have basically proved the fact that time travel to the future is possible, but persay if on wanted to travel back 30 years, why exactly would this be rendered impossible if we can go ...
0
votes
1answer
413 views

Faster than the speed of light and future travel [closed]

I had read somewhere that if a person attains twice the speed of light, he can actually reach the future. But since the world belongs to one time and space, how will it change for one particular ...
8
votes
3answers
2k views

How does faster than light travel violate causality?

Let's say I have two planets that are one hundred thousand lightyears away from each other. I and my immortal friend on the other planet want to communicate, with a strong laser and a tachyon ...
9
votes
3answers
1k views

What are some scenarios where FTL information transfer would violate causality?

I've always heard people saying, "Faster than light information transfer can't happen because it would violate causality! Effects can precede their causes!" However, I'm trying to think of a ...