Cosmic Microwave Background: The Universe’s Afterglow

The Cosmic Microwave Background (CMB) is faint radiation left over from the Big Bang.
It was released about 380,000 years after the universe began, when atoms first formed.
Before the CMB, the universe was an opaque fog of hot plasma.
The CMB shows the universe’s “baby picture,” just a fraction of its current age.
It fills the entire sky, bathing us in ancient light from every direction.
The temperature of the CMB today is only 2.7 Kelvin—just above absolute zero.
Tiny fluctuations in the CMB reveal the seeds of galaxies and cosmic structure.
The CMB was accidentally discovered in 1965 by Arno Penzias and Robert Wilson.
Satellites like COBE, WMAP, and Planck have mapped it in exquisite detail.
Studying the CMB helps scientists unlock mysteries of the universe’s origin, age, and fate.