Where exactely do you have to be in the universe for you to be still? We are on the Earth, but earth is orbiting the sun/galaxy/cluster/supercluster/etc. Because we are already going very fast, doesn't that mean that the speed of light is faster when we slow down? We've measured the speed of light, but is that the speed only when we assume Earth is standing still? Ive never known a clear answer to this, please enlighten me.