distance indicator

Last week, the brightest gamma-ray burst ever was observed. (See here.) I wanted to know what it was that caused this bright explosion that, despite it being at redshift z=0.94 (or about 7.5 billion light years away), it was visible on Earth with the naked eye! Well, a scientific paper was written on the observations of this burst, named GRB 080319B, or the second GRB observed on 03/19/08. Let me take you through the highlights. First off, here's what it looked like, in gamma-rays (left) and the afterglow in the optical/UV (right): When we look from Earth, the faintest objects we can see…