In simple terms, what is the Big Bang Theory?

Question

Alexander Acosta · Accepted Answer

In simple terms, the Big Bang Theory is the leading explanation of how the first moments of the Universe; the beginning of the Universe
See the explanation for less-simple terms.

The majority of scientific explanations for the Big Bang are derived from mathematical formulas and models because scientists do not currently possess the technology to peer back in time to the moments of the Big Bang. Nevertheless, scientists are able to observe the Big Bang's echo through cosmic microwave backgrounds. When the universe first began, its temperature was approximately 5.5 billion degrees Celsius (10 billion Fahrenheit). Protons, neutrons, and electrons were among the many particles that were present in the cosmos at this time. These particles decayed and combined as the universe cooled, forming a variety of elements, some of which are still in existence today. (Source: https://tutor.hix.ai 25126)

Christopher Ales · Answer

undefined The Big Bang Theory is a scientific theory that explains how the universe started and developed. It suggests that the universe was once a hot, dense point that expanded and cooled over billions of years, giving rise to stars, galaxies, and planets. This process of expansion began approximately 13.8 billion years ago.