"Our whole universe was in a hot dense state..." (Theme song lyrics). "Nothing bonds people quite like the Vulcan salute. 🖖" :

: The universe expanded from an extremely small, hot, and dense state and has been cooling ever since.

Depending on whether your image is about the or the popular TV show , here is useful text and context to accompany it. For the Cosmological Theory

: Key proofs include the Cosmic Microwave Background (CMB) and the observed expansion of space.

: Most physicists believe the universe was born approximately 13.8 billion years ago .