This was
your sky.

Planck Maps the Microwave Background

The Planck satellite mapped slight temperature differences on the cosmic microwave background, the oldest surface in our universe. This background radiation was left over from billions of years ago, when the universe first became transparent to light. Planck's detailed map helps us understand the composition of our universe. The hot and cold patterns observed could only exist if the universe were made of specific types of energy that evolved in particular ways.