cosmic microwave background radiation cosmic microwave background radiation

The Dark Sector Lab (DSL), located 3/4 of a mile from the Geographic South Pole, houses the BICEP2 telescope (left) and the South Pole Telescope (right). Steffen Richter/Harvard University hide caption

toggle caption
Steffen Richter/Harvard University

Cosmic microwave background radiation (CMB) as observed by Planck. The CMB is a snapshot of the oldest light in our Universe, imprinted on the sky when the Universe was just 380,000 years old. Planck Collaboration/ESA hide caption

toggle caption
Planck Collaboration/ESA