Question

what is big bang thoery

Answer 1

It is that in which our universe began from extreme hot condition and as well as dense one..

Answer 2

Answer:

The Big Bang theory represents cosmologists' best attempts to reconstruct the 14 billion year story of the universe based on the sliver of existence visible today. The Big Bang Theory is the leading explanation about how the universe began. At its simplest, it says the universe as we know it started with a small singularity, then inflated over the next 13.8 billion years to the cosmos that we know today.

While the majority of the astronomical community accepts the theory, there are some theorists who have alternative explanations besides the Big Bang — such as eternal inflation or an oscillating universe.