Renewable Revolution

If You Think Jupiter Orbits the Sun, You're Mistaken     
BY CHRISTOPHER HASSIOTIS AUG 9, 2016


If we picture the solar system, we often picture our dominant star at the center of things, static and immobile as planets orbit circles around it. That picture makes things simple to understand, but technically it's inaccurate. Take our largest planet Jupiter, for instance. It doesn't orbit the sun's center — it orbits a spot in empty space between it and the sun called the barycenter. This is because the sun doesn't just exert gravity on Jupiter — Jupiter's so big that its own pull affects how the sun moves, too.

The sun is about 1,000 times more massive than Jupiter, and these two bodies affect one another proportionally according to distance and mass, so the amount Jupiter's gravity pulls on the sun is one-thousandth the amount the sun's gravity pulls on Jupiter. And Jupiter's orbit takes 11.8 Earth years to complete, and the sun travels around the barycenter takes the same amount of time.

The Sol-Jupiter barycenter sits 1.07 times the radius of the sun from the sun's center, or 7 percent the radius of the sun from the surface. The sun also orbits this spot; if you were to look at the planetary plane from above, you'd notice a slight wobble as the sun moves around the Milky Way, as this hypnotic NASA animation helps explain.

https://science.howstuffworks.com/jupiter-orbit-sun-barycenter.htm