What is the Big Bang Theory?

The Big Bang Theory is a scientific theory about how the universe started. It says that everything in the universe began about 13.8 billion years ago from a single, tiny point that was extremely hot and dense. Then, this point exploded and began expanding, which is what we call the Big Bang.

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As the universe grew bigger, it cooled down. This allowed tiny particles to come together and form atoms. Over millions of years, these atoms created stars, planets, and galaxies—the universe we see today.

The theory doesn’t explain what caused the Big Bang or what existed before it, but it helps us understand how the universe has grown and changed since that moment.