Most of the light streaming through the Universe is invisible to human eyes. Beyond the mid-range wavelengths we can see, there’s a whole cosmos shining in high-and low-energy radiation.
But we humans are clever little animals and have managed to build instruments that can see the light we cannot. One of these is NASA’s Fermi Gamma-ray Space Telescope, an observatory hanging out in low-Earth orbit, monitoring the sky for gamma rays, the highest-energy light in the Universe.
Fermi constantly surveils the entire sky, observing gamma-ray sources and how they change over time, providing astronomers with a map of the various producers of gamma radiation that we can detect. This data is compiled into a catalog that scientists can use to probe the production of gamma radiation.
