Q&A: Cosmology

Q:
How can I find the absolute diameter and distance away of an object?

A:
For small red shifts, the distance d = z c/H, where z is the red shift, c is the speed of light, and H is the Hubble constant. The absolute diamete D is related to the angular diameter A by D = Ad, where A is in radians. For red shifts greater than about 0.1 See: http://www.astro.ucla.edu/~wright/CosmoCalc.html .