[quote=“renke, post:36, topic:71892, full:true”]
according to the image description it’s the barycenter of the solar system, not the earth/sun system[/quote] Right you are - the Earth and Sun both revolve around the barycenter (as does everything else in the solar system. (This diagram portrays the barycenter’s position relative to a fixed heliocentric POV. The sun, of course, is actually moving - like everything else.)
Because, as @renke notes above, that’s the baycenter of the entire solar system, not just the Earth and Sun.
Why does it wander like that? Because Jupiter.
(…and Saturn and Uranus and so on - but mostly Jupiter.)
