pic: VEX Solar Tracker Gearbox

[Ether]

Originally Posted by gblake

Also, if you want to describe the Earth-Sun situation as a two body system (and ignore all the other influences on their relative motions) you will often (but certanly not always) choose to say that the two bodies move relative to a point that is in-between their centers-of-gravity, not around the center-of-gravity of the larger mass.

Just to put this in perspective though: On a scale where the Sun is the size of a basketball, the center of mass of the Earth/Sun system would be approximately 3 thousandths of an inch from the center of the basketball.

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