obviouly the speed of light is constant when we are measuring it here on earth however as mater speeds up time slows down. so if we were to measure the speed of light standing on a planet moving at the speed of light. what speed would we then be viewing light at? oh i do know that it is looking impossible at the moment for anything to move at the speed of light. i also know that it will be possible to work out any speed variations even though it is not possible for anyone to travel at light speed and see it through there owns eyes at the moment. however i just dont know how to do it myself and i am guessing that somebody else has already worked it out anyway!