How do the planets orbit the Sun?

1 Answer
Jan 13, 2017

The Sun and other planets orbit around the Solar System Barycentre.


It is actually incorrect to say that the Moon orbits around the Earth or that Earth and other planets orbit around the Sun. In fact the Moon and the Earth both orbit about their centre of mass.

Likewise, the Sun and all of the planets all orbit around the centre of mass of the Solar System. This centre of mass is called the Solar System Barycentre (SSB). It is constantly changing position as the relative positions of the planets change. The SSB can be anywhere from the centre of the Sun to about two solar radii from the centre of the Sun.

The diagram shows the position of the SSB plotted over time from 1946 to 2052.
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