What is the barycenter of the solar system?

Answer 1

The barycenter (or barycentre; from the Greek βαρύκεντρον) is the point between two objects where they balance each other. In other words, it is the center of gravity where two or more celestial bodies orbit each other. When a moon orbits a planet, or a planet orbits a star, both bodies are actually orbiting around a point that lies outside the center of the greater body. For example, the moon does not orbit the exact center of the earth, instead orbiting a point outside the earth's center (but well below the surface of the Earth) where their respective masses balance each other. The barycenter is one of the foci of the elliptical orbit of each body. It seems to me then, that each planet has its own different barycenter with the Sun. It is a relation between two objects, and since their are nine planets I don't think the term applies to an overall relation between the Sun and all the planets at once. On the other hand, the definition above does say "...where two or more celestial bodies orbit each other." It is true that the planets are not orbiting one another, but each of the planets is affected by every other as well as by the sun. There might therefore be a single solar system barycenter, and it would likely never leave its wandering path deep within the sun. I don't think it's an idea that will have much use any time soon.