I have a couple questions about relative motion, since I've been reading everywhere that motion is relative... (Feel free to point me to other threads that answer these questions if there are any - I searched and couldn't easily find any) QUESTION #1 So if I'm standing still, and someone travels away from me at almost the speed of light, noticeably less time will pass for him than for me, right? But his motion and speed are being measured relative to me, right? And that means that I am also traveling away from him at almost the speed of light. So time should slow down for me also. But it doesn't. How can that be explained? QUESTION #2 Let's say that me and 2 friend are hanging out in space. Friend #1 gets on his rocketship and zooms off to my right at 75% of the speed of light. Friend #2 gets in his rocketship and zooms off to my left at 75% of the speed of light. Relative to me, both friends are traveling at 75% of the speed of light. But relative to each other they are traveling at 150% of the speed of light. But nothing can travel faster than light. So something impossible is happening. How can that be explained? Thanks in advance for any answers.