horizon problem


horizon problem

See inflation.

horizon problem

[hə′rīz·ən ‚präb·ləm] (astronomy) The problem of explaining the observed uniformity of the universe, and in particular of the cosmic background radiation, when, according to the standard big-bang theory, sources of radiation coming from opposite directions in the sky were separated by manyfold the horizon distance at the time of emission, and thus could not possibly have been in physical contact.