The Big Bang Theory
Have you ever wondered how the Earth and solar system was made? Well scientists think they have the answer: The Big Bang Theory. The Big Bang Theory is the theory of how everything in the universe was formed. It starts with a single point called a singularity. Then, all of the sudden, it exploded in less than a second, and everything we know today, planets, stars, black holes, etc, was put into place. However, the name isn't very accurate because it wasn't really a "big bang". In fact, it didn't make a sound at all. Also, the universe was expanding, and as it expanded, it got cooler and less dense.
As space expanded, the universe cooled and matter formed. Some of this matter collided to form stars, planets, and galaxies.