If two spaceships travel in opposite direction at .6c (the speed of light) from earth, then why aren’t they exceeding the speed of light relative to each other?

Question

I understand that if I am standing on earth and a space ship takes off and travels at .6c, then I perceive the space traveler receding at .6c relative to me, and the space traveler perceive me as receding at .6c relative to him. If another traveler takes off in the 180-degree opposite direction, then likewise I perceive the other space traveler receding at .6c relative to me, and the other space traveler perceive me as receding at .6c relative to him.

So why don’t they perceive each other as traveling faster than c, the speed of light?

In: 29

Answer 1

neither spaceship agrees about how fast the other is going. both of them will see themselves as traveling .6c, but both will observe the other going slower because of time and length dilation. this holds true, no matter what frame of reference you observe from, nothing will ever exceed the speed of light from any point of view.