John I dont see why space expanding needs to invalidate relativity, to me both are true, if the ruler itself is expanding, why wouldn't it be? Isn't it an assumption to presume that the distance we perceive to be between two "stationary" points on Earth is not itself expanding, and that we ourselves are not expanding? Doesn't it also explain the acceleration force we perceive as gravity, if we, and the mass we are standing on is also expanding?