Hi, I've always had a doubt concerning time dilation, and today the curiosity got the best and I decided to ask people that know their stuff, you people. Maybe the question has been asked before, but I did a quick search and couldn't find it, sorry if that's the case. Well, here it goes. As I understand, time dilation occurs by different velocities or positions relative to a gravitational field. In the case with velocity, I understand that if an observer has a clock, let's call it clock A, and there is also a second clock (clock B) moving relative to the observer, then clock B will register a slower passage of time than clock A. Now my question is this, if velocity is relative, why does clock B ticks slower, if from the point of view of clock B, it is clock A that's moving, and should therefore be the slower clock? Are both clocks slower? How does that work? I'm not a physicist (biologist here!), so my understanding of these things is shallow at best. Any help would be greatly appreciated.