Relativity, Trick Question?? 1. The problem statement, all variables and given/known data Two Space Craft are flying towards a planet at 0.9c and 0.3c relative to the planet, respectively. if they fire their laser beams simultaneously from a range of 10^9m, which will strike the planet first and what will be the delay before the other beam strikes? 2. Relevant equations Ua = (Ub + v)/(1+Ub*v/c^2) Ua = speed of beam relative to planet Ub = spped of beam relative to ship v = speed of ship relative to earth c = speed of light 3. The attempt at a solution A laser beam is just light isnt it? im sure it is. even more so since theres no values for speed of beam. but if speed of beam is c then Ua = Ub since c is the same in all reference frames. Then since the beams are fired simultaneously from equal distance, and they're equal speed, they should hit at the same time Also, using formula and letting Ub = c, then Ua = c. so beams hit at the same time and there is not time before other beam strikes. It just seems strange to me that they write up a question like this and its really really simple, its not very often you see numbers in questions that arent relevant. so i just automatically doubt myself. Opinions?