The sun is the gravitational powerhouse of the solar system. In fact, more than 99% of the total mass in our solar system is contained within the sun. All the planets, asteroids, comets, meteors, and dwarf planets comprise less than 1% of the solar system’s mass. It probably comes as little surprise that the sun is capable of holding everything in the solar system in its orbit. However, although the sun exerts the strongest gravitational field in the solar system, all of the planets also exert a gravitational force that pulls on the sun. Since Jupiter is the most massive planet in the solar system, it pulls on the sun more strongly than all the other planets. 

　　

Center Of Gravity

            Image of Jupiter taken by the Juno spacecraft. Image credit: NASA/ESA Every object in the universe that has mass exerts a gravitational force. The Earth’s gravity is currently pulling you towards the surface, yet you yourself are also exerting a gravitational pull on the Earth. Since the force of gravity is proportional to your mass, the gravitational force you exert is virtually non-existent compared to the Earth. However, between any given objects, there exists a center of gravity. The center of gravity is defined as the location where the force of gravity is at its strongest. For example, an object that is uniform and experiences no external force of gravity will have its center of gravity at its center. A star in empty space with no other objects near it will have its center of gravity located at the center of its core. When two objects exert a gravitational pull on each other, however, the center of gravity will move away from the center of the more massive object and towards the smaller object. How far the center of gravity is located will be dependent upon the mass of the two objects and the distance between them. The two objects will then orbit around the center of mass.

　　

Center Of Mass In The Solar System

Since all the planets exert a gravitational pull on the sun, there exists a center of gravity between them. For most of the planets in our solar system, the center of gravity exists either at or near the core of the sun. That’s because the sun is so much more massive than all the planets, yet there is actually one exception to this. The center of gravity between the sun and Jupiter actually exists outside of the sun’s surface. Thus, the sun and Jupiter actually orbit this point. Technically, the two objects orbit each other, although Jupiter’s orbit around the sun is much more obvious. The gravitational pull of Jupiter causes the sun to move in a small orbit around a point that exists outside of the sun itself. Although the sun does not technically orbit Jupiter, the gravitational pull of the gas giant does cause the sun to move. 

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