Electromagnetic radiation left over from the early universe, about 380,000 years after the Big Bang. It is the oldest light in the universe, now cooled to about 2.725 Kelvin. The CMB is crucial evidence for the Big Bang theory.
The prevailing cosmological model explaining the origin of the universe from an initial state of extremely high density ...
An increase in wavelength of radiation from an object moving away from the observer. The redshift of distant galaxies pr...
A hypothetical form of energy that permeates all of space and drives the accelerating expansion of the universe. It cons...
Dive deeper into cosmic microwave background and related concepts on Cosmos Observatory.