“I happen to have discovered a direct relation between magnetism and light, also electricity and light, and the field it opens is so large and I think rich.” -Michael Faraday
With the launch of the Fermi satellite in the late 2000s, we began observing the highest energy photons in the Universe — gamma rays — all over the sky, to unprecedented precision. Produced from cosmic ray showers in space when high energy protons run into other, stationary protons, these gamma rays locate point sources from supermassive black holes to supernova remnants to pulsars.
There is, additionally, a great correlation between the infrared sky and the gamma ray sky, since the great high-energy background scatters off of the diffuse infrared gas, producing gamma rays there as well. But while a great many sources can be correlated with known structures, Fermi reveals at least one unknown, intense behemoth that emits spectacularly in gamma rays.