What is " Cosmic Microwave Background? "

Planets, interstellar gas, and stars that illuminate the night sky account for only 15% of the matter in the universe. So, how important is a "Cosmological Signature" and what is "Cosmic Microwave Background?" What does either have to do with scientists' search for invisible, dark matter, 85% of ...This is an NSF Multimedia Gallery item.

Source: NSF Multimedia Gallery - July 20, 2022 Category: Science Source Type: video