4 ms·

This page looks to answer your question with a fairly comprehensive "we're not sure": http://www.desy.de/user/projects/Physics/Relativity/SpeedOfLight/FTL.html#

This page looks to answer your question with a fairly comprehensive "we're not sure": http://www.desy.de/user/projects/Physics/Relativity/SpeedOfLight/FTL.html#18 http://www.desy.de/user/projects/Physics/Relativity/SpeedOfL... (I can't vouch for its accuracy. It seems that the grandfather paradox is the biggest problem with FTL communication)

raganwald 15y ago
The suggestion seems to be that FTL communication is equivalent to sending information back in time. But the explanation on this page asks me to make massive leaps. I can only imagine it is not meant to explain, but rather as a reminder for people who already understand the explanation.