I have been looking at several articles recently about the Rh = ct cosmology, but none of them have explained the meaning of the equation. They just assume than anyone looking at such an article will already know what it means. I guess that (1) h is the Hubble "constant", and (2) c is the speed of light, and (3) t is some kind of time. But R is a mystery. R must be a units like m s, but i can't think of what such a variable might be. Will someone please explain this?