I have a very basic question about Special Relativity. I am very limited on my knowledge of physics and math and even more so on SR so please keep that in mind when answering. I have read the basic example many times of two spaceships traveling towards each other with a constant velocity. The observer on ship A could say that his ship is moving while ship B is at rest and he could also say that his ship is at rest while ship B is moving. The observer in ship B could also say the same things. That was all fine until I thought about one of the ships changing into a beam of light. If a beam of light is used the observer on the ship could still say that he is at rest and the light is moving but it doesn't seem that he can say that the light is at rest and he is moving. This would cause his ship to be moving at c which is impossible since it has mass. Someone pointed out that the observer couldn't see the light until it reached him but you could easily fix that by saying the light has already hit the observer on the ship and continues to pass him. In other words, the beam of light is arbitrarily long and continues to pass by the ship. Thus the observer should be able to say he is moving or the light is moving. If even that won't work, what if it were a beam of light as one reference frame, and then another beam of light and the rest of the cosmos as another? Then the light and cosmos could say the other light beam is moving and they are all at rest, or that they are moving and the other beam of light is at rest - which again causes the matter in the cosmos to be moving at c. I just don't see how a beam of light can be a frame of reference. The only thing I can think of is that maybe when taking the frame of the light time for the other frame (the ship) stops. But that seems to just enforce the idea that the light must be moving and no other reference can be taken. And you still couldn't take the reference frame of the ship and say the light is at rest because you would have to be moving at c. I don't see how any affect on time would change this for the ship. I'm sure I'm looking over something obvious but I just don't understand. I'd appreciate some help.