The COBE satellite, launched in 1989, carried the study of microwaves into space and confirmed that the universe began in a hot fireball. Visible light is only one way to look at the universe. Each strip below shows the plane of our galaxy in a different part of the electromagnetic spectrum, revealing unique information. Radio continuum is from hot, electrically charged gas. Atomic hydrogen emission comes from warm gas.
Molecular hydrogen lies in cold clouds, where stars form.
Visible light is mostly from sunlike stars. Ultraviolet is heavily obscured by interstellar junk. X rays come from energized gas. Gamma rays appear where high-speed subatomic particles collide with interstellar hydrogen. The prominent mass of agitated gas, known as Sagittarius A, marks the exact hub of our galaxy and may contain a massive black hole.