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Everything in the space is moving all the time.

Do the orbit of major Solar Systems planets, Mercury to Saturn change? Just like Moon's orbit around Earth changes. How often, how small or big is the change? Where can I find data on this?

Majoris
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    Mercury's perihelion precesses greatly over relatively short timescales. – WarpPrime Feb 07 '21 at 23:26
  • Data on this please ?! – Majoris Feb 07 '21 at 23:31
  • There are many answers to Where can I find the positions of the planets, stars, moons, artificial satellites, etc. and visualize them? and I think one of them will likely be just what you need. Feel free to write an answer to your own question if you find what works for you. However if you'd like to know more about long term Secular perturbations that's a whole 'nuther ball of wax. On the scale of millions of years the planets (major and minor) really dance around quite a bit! – uhoh Feb 08 '21 at 01:09
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    Uranus and Neptune feel slighted by being left out of your list of major solar system planets. Both are much more massive than the Earth. – David Hammen Feb 08 '21 at 14:11
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    Highly related, if not a duplicate, Advancement of perihelion, data. – David Hammen Feb 08 '21 at 14:13
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    @fasterthanlight Mercury's perihelion precession is ~532 arc-seconds per century, i.e., it takes ~676 years to precess by 1°. That's not very fast. ;) In contrast, the Moon's apsidal precession period is only 8.85 years, i.e., ~9 days per degree. – PM 2Ring Feb 08 '21 at 15:16
  • Orbits change due to perturbations from other planets and long term can mostly be put to cycles, on Earth, these are called Milankovich cycles and are well documented. Mercury also has a noticeable relativistic effect which adds to it's precession. You also get tugging on individual orbits (a famous example of this lead to the discovery of Neptune), so orbits do change because gravity is everywhere. The Moon's orbit also moves very slowly from the Earth due to tidal forces, but that's small and slow but it's consistent unlike perturbations with generally move in cycles back and forth. – userLTK Feb 09 '21 at 23:27
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    I'm not sure this is a good question for stack exchange because, other than "yes orbits change, but for the most part slowly and often cyclically", for any detail, this would be more like a chapter in a textbook on orbital mechanics rather than a stack exchange answer. Is there a specific orbital movement you're asking about? – userLTK Feb 09 '21 at 23:29
  • @userLTK Yes, I think so, I have so many questions on orbital mechanics that there are no ready answers. Any suggestions for a good book for orbit mechanics? – Majoris Feb 12 '21 at 08:06

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