More to the point, you Wiki quotes Einstein's theory of relativity as the explanation for why UA doesn't exceed the speed of light. However, Einstein's theories explain gravity as a distortion space/time. This only work with a spherical earth, and explains why the earth is spherical, why the atmosphere doesn't get sucked into space, why the water doesn't fall off the south pole, etc. Why are you 'cherry picking' the parts of his theories that suit you, but are ignoring the parts you don't like.