http://hyperphysics.phy-astr.gsu.edu/Hbase/relativ/einvel.html#c1 ok, so i'm looking at this, and i see that where c = speed of light if ship A is moving at .7c to the right ===> <=== and ship B moving .7c to the left and they are both on the same line and about to collide, at what velocity (in C) will they hit each other. the reference point is the collision point of impact not some distant observer. Theory i read appears that C + X = C but this seems to violate common sense. I can even imagine that you can't possible surpass the speed of light, but can someone make this a little more obvious. Thanks, and this is not a HW question, i'm in EE. i'm just asking for the fun of it.