As I barely understand it, objects are not prevented from travelling faster than light by general relativity.
Objects are prevented from acceleration to and beyond the speed of light.
Disclaimer: I learned this on YouTube.
Disclaimer: I learned this on YouTube.
Imagine if you are on a sheet of stretchy fabric, that represents spacetime. If you stretch the sheet from corner to corner at and even rate, things at the edge travel faster away from the things in the center of the sheet. They themselves are not traveling, spacetime is expanding around them.
> Next, Einstein also showed that if you have any particle which moves slower than the speed of light, then you cannot accelerate it to faster than the speed of light. You cannot do that because it would take an infinite amount of energy. And this is why you often hear that the speed of light is an upper limit.
> However, there is nothing in Einstein’s theory that forbids a particle to move faster than light. You just don’t know how to accelerate anything to such a speed. So really Einstein did not rule out faster than light motion, he just said, no idea how to get there. However, there is a problem with particles that go faster than light, which is that for some observers they look like they go backwards in time. Really, that’s what the mathematics says.
https://backreaction.blogspot.com/2020/05/is-faster-than-lig...
(Sabine Hossenfelder, Theoretical Physicist, Research Fellow at the Frankfurt Institute for Advanced Studies)