+Simon Dainty: However, the experiments in QM, and the arguments on why FTL is impossible, do not specify
how information travels - it simply says that if information from Event A can reach Event B in less time than would be required for light to travel that distance, Bad Things Will Happen (tm). You'll get violations of causality, time travel, etc. The situation where spooky action at a distance, involving the correlation of entangled particles, supposedly side-steps this slightly by saying that the correlation cannot usefully be used to transmit information. You're making the SciFi Time Traveler's Mistake, thinking that it takes macroscopic events such as Kennedy's Assassination to create a branch in the Universe - it's not, it's
every possible event within every Planck volume, within every Planck time, and it's not binary splits- it's
EVERY possible outcome. Likewise for the transmission of information - the important thing here is that if even a single bit of information can be transmitted FTL, even if it hitches a ride with something that does and doesn't go FTL, that causes
issues.