ELI5: Explain Like I'm 5

Geocentrism

Geocentrism is an idea that people used to believe long, long, long time ago. They thought that the Earth was at the very center of everything in the universe. It was like the middle of a big target, and everything else, like the Sun, the Moon, the stars, and planets, all went around the Earth. This idea used to be very popular because it seemed like everything in the sky was moving around the Earth. However, this idea is not true, and modern science has proved that the Earth is not exactly at the center of everything moving in the universe. Instead, we know that the Earth orbits around the Sun, and that the Sun is just one of many stars in the Milky Way Galaxy. So although the idea of geocentrism might have seemed right a long time ago, now we know it was just a mistake.