This chapter is going to examine the most powerful explosions in the Universe that can be observed today and also study the Big Bang origin of the Universe itself – an explosion of a very different and unique type. The story begins with the serendipitous discovery, which came out of the Cold War, of what are termed ‘gamma-ray bursts’ or GRBs.

It is an interesting point as to what ‘today’ means. We see these events now but, as we will see, they arise in galaxies in the distant reaches of the Universe and so we are seeing events that actually happened many billion of years ago.

The discovery of gamma-ray bursts

As nuclear test ban treaties were negotiated in the late 1950s, President Eisenhower’s science advisors cautioned him that the USSR might try to secretly carry out nuclear tests in space. It was decided to design and launch a series of satellites that could detect the characteristic double burst of gamma rays (very highly energetic photons) that results from a nuclear blast.