Space seems dark to our weak human eyes.  Most of the night sky is the blackness between stars.  But in this darkness lies an endless number of photons, travelling in all different directions.  These photos form background radiation, in three wavelengths in particular.  You’ve likely heard of the Cosmic Microwave Background (CMB), it there is also a Cosmic Optical Background (COB) and a Cosmic Infrared Background (CIB). The COB is explained by the immense number of stars in the Universe.  It’s a diffuse glow across the entire sky.  The CMB is the leftover radiation from hot plasma that existed when the Universe...