[blue character points at a square] We've done a peer reviewed study, and concluded that all squares have four sides
[annoyed orange character points at a diamond shape] This is objectively wrong, I've personally seen a four sided structure that isn't a square
Obligatory xkcd:
This made me fucking angry to read. I haven't seen this one yet.
Why did it make you angry? All gravitationally bound objects orbit around a common center. For the solar system that center wobbles around inside the sun depending on where Jupiter and Neptune are in their orbits. The rest of the mass of the solar system does contribute, but it is generally negligible for most conversations. This is actually one of the ways that exoplanet hunters have found literally thousands of planets in the last decade or so.
The moon is the center, obviously