Question

what is mean by observable
universe​

Answer 1

Answer:

In Big Bang cosmology, the observable universe is what, in theory, can be seen from Earth. That is light, or other signals,[1] which has had time to reach the Earth since the beginning of the cosmological expansion. The observable universe is a spherical volume (a ball) centered on the observer, regardless of the shape of the universe as a whole. Every place in the universe has its own observable universe, which may or may not overlap with the one centered on Earth.