Here's why:

* Planets orbit stars. The Earth and other planets in our solar system orbit the Sun.

* Stars produce their own light and heat. The Sun is a giant ball of hot gas that generates its own energy through nuclear fusion. Planets don't produce their own light or heat.

* The Sun is much larger than planets. The Sun makes up over 99% of the mass in our solar system.

So, the Sun is the central star in our solar system, and our Earth orbits around it.