The double firing burst (artist's impression)

The gamma-ray burst GRB 080319B was so intense that, despite happening halfway across the Universe, it could have been seen briefly with the unaided eye. Astronomers from around the world combined data from ground- and space-based telescopes to conclude that the burst's extraordinary brightness arose from a jet that shot material almost directly towards Earth at almost the speed of light - the difference is only 1 part in 20 000. This 0.4 degree wide jet is contained within another slightly less energetic jet about 20 times wider. It also appears that the jets were aimed almost directly at the Earth.