English: From its orbit around Earth, the Goddard Space Flight Center's Cosmic Background Explorer (COBE) captured this edge-on view of our Milky Way galaxy in infrared light, a form of radiation that humans cannot see but can feel in the form of heat, as part of its mission to test the "Big Bang" theory of the creation of the universe. The theory, first proposed in 1927 by Belgian cosmologist Georges Lematre, holds that the universe began as an incredibly dense "primeval atom" that exploded with tremendous force, unleashing matter and space at the speeds of light. NASA set out to prove the theory with the help of COBE. In addition to proving the Big Bang, the satellite discovered that the cosmic background radiation had indeed been produced in the Big Bang just as scientists originally speculated. The satellite's data even discovered the primordial temperature and density fluctuations that eventually gave rise to the Milky Way and other large-scale objects found in space today.