Scenario A very fine almost massless thread about 30 seconds at the speed of light long that can't stretch and can't break is strung out taut in a vacuum in space. It has a loop on one end. Suddenly Voyager 1 's as it passes by catches on the loop with it's antenna and gives it a tug. No part of the string travels faster than the speed of light but... the other end moves instantly. I know the thread is fictitious and can't exist but if something like that existed could it happen? Kind of a long Newton's cradle.