Hi. I just started learning special relativity in my physics class. The prblem is i don't get this point. My teacher said that 2 inertial frames (A and B) where A moves with speed v relatively to B. He says that two flashes of light F1 and F2 occur when the 2 frames are at the same position. So, he says that an observer in B sees the 2 flashes as simultaneous cause he isn't moving. However A is moving making the distance between him and flash F1 bigger and between him and flash F2 shorter. So he says that from B's point of view F2 occurs before F1. Well, i don't get this. If the speed of light is constant then A should also see them as simultanious. if the F1's moves towards A at speed c and F2's speed relative to A is also c they should reach him at the same time. Can someone plz explain me this? BTW, why should we say that A is moving towards F2 and it's not B that's moving towards F1???? I thought it was relative. We can't say if it's A moving away from B or B moving away from A.