The universe is so massive that we'll never know all its secrets. But, little by little, astronomers are getting a better handle on how big and powerful the universe really is.
Case in point: Astronomers have figured out a way to depict X-ray wavelengths, which occur at mind-bending temperatures. Objects like black holes are heated to millions of degrees. When stars explode or galaxies collide, they produce photons that are heated to millions of degrees. Galaxies with hundreds of trillions of stars also get that hot.
Those high temperatures are shown on the photos above and below. The images were recently created by astronomers at the Max Planck Institute for Extraterrestrial Physics, using data collected in the 1990s by the ROSAT X-ray satellite's all-sky survey.
Each dot on these maps represents a source of X-ray in the universe. The color lets astronomers know what the source of the X-ray is, while the brightness depicts its size. The brightest objects here are black holes.