The Sun has a vast effect on the motion of planets in our solar system. And, in turn, the planets affect the motion of the Sun. Even though the planets are much smaller than the Sun, they still exert a certain gravitational pull on it. This pull causes the Sun to “wobble” in its orbit while in the presence of another planet. These wobbles are called gravitational perturbations. They were also observed in the orbit of the planet Uranus which led astronomers to discover Neptune. In other words, astronomers only realized that Neptune existed because of how its gravitational pull changed Uranus’ orbit. It was this same type of situation which led to the discovery of Pluto. Now it is possible to detect planets around distant stars which would otherwise not be possible to see with a telescope!
