Here's why:
* The Sun is the center of our solar system. Planets, including Earth, orbit around the Sun due to its gravitational pull.
* Orbits are elliptical, not rectangular. The shape of an orbit is determined by the gravitational forces involved. Ellipses are the natural shape of orbits in a two-body system.
It's important to remember that the Sun is a star, and stars don't orbit other objects.