observable universe
Astronomy term for the spherical region of the universe that can be observed from Earth, limited by the speed of light and the age of the universe.
The diameter of the observable universe is estimated to be about 93 billion light-years.
Compound of 観測可能 (observable) + な (attributive) + 宇宙 (universe). A direct translation of the English term 'observable universe', used in modern astronomy.