An orbit is a circular path around a bigger object. When a planet, like Earth orbits the Sun, it is going in circles. An orbit is caused by the gravitational pull of an object. A big object, like the Sun or other stars, have a stronger gravitational pull. Since there are smaller objects (planets) around the Sun, they start to spin around the Sun or orbit. This is because the gravitational pull of the Sun draws all of the planets into orbit! Orbits are not just for the Sun and planets! It is also for moons! Moons also orbit around planets because of the gravitational pull. These orbits have to be stable orbits, which means that the orbit is not too slow and not too fast. That is how the planets orbit around the Sun!