I see from Astropixels.com that Earth's aphelion and perihelion each vary by a little over 29,000 km, while the earth-moon barycenter wobble is about 4,000 km. Is Astropixels.com correct? Are Jupiter and Saturn the major forces behind the rest of this variation?

  • $\begingroup$ Jupiter and Saturn are always the "usual suspects" for these kinds of things. Their effects are on both the Earth directly, and on the Sun, which the Earth then follows. Can I ask what "the earth-moon barycenter wobble" means exactly? The barycenter wobbles with respect to what? $\endgroup$
    – uhoh
    Commented Feb 15, 2018 at 3:15
  • 1
    $\begingroup$ I should have said that Earth's rotation around that barycenter is about 4000 km. $\endgroup$
    – user16692
    Commented Feb 15, 2018 at 23:01


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