State the Big Bang theory.

Question

Accepted Answer

The Big Bang theory states that the universe originated from the huge explosion of a highly compressed, energetic single atom. Before the explosion, the four fundamental forces of nature were unified as a single force. Due to excessive pressure, the atom exploded, and all celestial bodies in the universe originated from this explosion. Since then, the universe has been expanding continuously, though its speed of expansion is slowly decreasing due to gravity.