We already have an answer why physically traveling faster than light would violate causality (the clock on board our hypothetical FTL spaceship would tick backwards to some outside observers). ...
Can superluminal travel or communication be possible without leading to the possibility of closed timelike curves (CTCs) and causality violations? I have seen conflicting opinions regarding this ...
Mathematician here with a speculative physical question -- feel free to boot me if the level isn't right. Suppose one finds, or builds, a constellation of several black holes arranged in a circle. ...
From the wikipedia article on tachyons: Most physicists think that faster-than-light particles cannot exist because they are not consistent with the known laws of physics. If such particles ...