Blast From the Past
The SWIFT spacecraft is designed to catch gamma-ray bursts on the fly. An explosion detected by SWIFT in the constellation Bootes is the most distant object visible to the naked eye. GRB 080319B is estimated to be 7.5 billion light-years away, with a luminosity 2.5 million times greater than the brightest supernova. SWIFT has imaged the gamma ray burst in X-rays (left) and optical/UV (right). The next most distant visible object is the Andromeda galaxy, only 2.9 million light-years. Here is a place many agree we could find a Black Hole.
The Black Hole would be supermassive, like that at the centre of our galaxy. Since GRB 080319B exploded when the Universe was less than half its present age, the Black Hole must have grown to this size long before. Theories of collapsing stars could not explain something so massive and so old. The Black Hole may even be primordial, formed in the immense temperatures and pressures follwing the Big Bang, Size of a PBH is limited by a horizon distance related to the speed of light. This blast from the past is a signal that the speed of light may have once been much larger.
(Hat tip to Tommaso and Kea)