Hi Jim

Best place for a mathematical description of cosmic distances is Prof. Ned Wright's tutorial here...

http://www.astro.ucla.edu/~wright/cosmolog.htm

...from the main page you can navigate to all sorts of handy tools, like the cosmic calculator...

http://www.astro.ucla.edu/~wright/CosmoCalc.html

...for example because the Universe has expanded since the Big Bang, the most distant galaxy recently discovered at red-shift z = 10 is now 31.5 billion light years away even though light from it has taken a mere 13.2 billion years to get here. Nothing within space-time has travelled faster-than-light, but space-time itself has expanded faster-than-light, which is fine in general relativity.

That's incidently how the Alcubierre warp-drive works - by expanding space-time in front of a ship and contracting it behind the ship.