What are the highest accuracy (and hence precision) orbital periods of Jupiter, Saturn and earth in units of days. Note have Allen’s Astronomical Quant(Cox1991)/ Wolfram-α / Wikipedia / 3ea. don’t agree.

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    $\begingroup$ Hi. It would be helpful to have links to all the references so that all the readers do not need to try to find them. Plus, there are different definitions of "orbital period", so that might be some of the discrepancies. If you can clarify which period you want, that would be helpful. $\endgroup$
    – JohnHoltz
    Oct 3, 2023 at 0:34
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    $\begingroup$ To be very precise, a planet’s orbital period is never the same from one orbit to the next, mostly because of gravitational interactions. I find Wikipedia and Wolfram Alpha to give the same values (though rounded for Wα), while Astrophysical Quantities (I have the 2002 edition) does give slightly different results; NASA’s Solar System Fact Sheet also differs slightly. The epoch of measurement would be important to know, as it can have an influence. $\endgroup$ Oct 3, 2023 at 1:16
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    $\begingroup$ @JoeHorwath I see things differently. With n-body problems like solar systems there's really no such thing as actual, purely periodic motion. All these definitions of "period" are artificially constructed, but none of these are going to really be periodic. If one were to measure each of them for a million hears, "period" after "period", and plot them, they'd all have scatter from one "period" to the next. I think a good follow up question would be "Why is 'period' such a complicated thing to define for solar system objects, and why are there so many different definitions for period?" $\endgroup$
    – uhoh
    Oct 5, 2023 at 23:45
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    $\begingroup$ @uhoh Sure, the period is variable on any n-body system for n>2, but Pierre already mention that. A mean period can still be useful, though. $\endgroup$
    – PM 2Ring
    Oct 6, 2023 at 1:10
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    $\begingroup$ @PM2Ring yep for sure etc. I'm just replying to the OP's comments here. $\endgroup$
    – uhoh
    Oct 6, 2023 at 2:12


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