Estimation based on steady-state universe Sir Fred Hoyle calculated the mass of an observable steady-state universe using the formula:  which can also be stated as or approximately 8 × 10 52 kg. Here H = Hubble constant , ρ = Hoyle's value for the density, G = gravitational constant and c = speed of light . Most distant objects The most distant astronomical object yet announced as of January 2011 is a galaxy candidate classified UDFj-39546284 . In 2009, a gamma ray burst , GRB 090423 , was found to have a redshift of 8.2, which indicates that the collapsing star that caused it exploded when the universe was only 630 million years old.  The burst happened approximately 13 billion years ago,  so a distance of about 13 billion light years was widely quoted in the media (or sometimes a more precise figure of 13.035 billion light years),  though this would be the "light travel distance" ( see Distance measures (cosmology) ) rather than the " proper distance " used in both
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This note was uploaded on 12/15/2011 for the course AST AST1002 taught by Professor Emilyhoward during the Fall '10 term at Broward College.