Gamma rays are about as extreme as you can get. The bursts are a million times brighter than entire galaxies. Per second, a single gamma-ray burst can produce as much energy as all the starlight in the observable Universe, he says. They are the most energetic form of electromagnetic radiation, and in space, they are signs of the hottest, most powerful processes in the Universe – such as solar flares and black holes gobbling up gas and dust. But because Earth’s atmosphere absorbs the rays, the gamma-ray universe was closed off to astronomers until the space age.
http://www.bbc.com/earth/story/20160714-the-biggest-explosions-in-the-universe
