Barycenter: The Earth Does Not Revolve Around the Sun

"Eppur si muove."
— Galileo Galilei

Even though the famous utterance is likely apocryphal, we have, nonetheless, known for hundreds of years that the Earth revolves around the Sun. And while Earth’s orbit does completely encompass the  Sun, technically, the point around which the Earth revolves is not the Sun. Rather, it is the center of mass of the Solar System — called the barycenter.

Barycenter of the Solar System

All the objects in the Solar System have mass and, therefore, generate a gravitational effect on all the other objects in the Solar System. This means giant Jupiter and tiny Mercury (and even non-planet Pluto) all pull on the Sun, and each other. The combined effects of all the gravitational effects means that the center of mass of the Solar System is not the center of the Sun.

The barycenter is sometimes close to the center of the Sun, and, oftentimes, it is within the Sun. Depending on the position of the planets, however, it is frequently not actually located within the Sun. At these times, the Earth, in a manner of speaking, does not revolve around the Sun.

This entry was posted in FFFC. Bookmark the permalink.

Leave a Reply

This site uses Akismet to reduce spam. Learn how your comment data is processed.