Earth has a time period of 26000 years approximately for precession of its equinoxes.

What are the time periods of precession of equinoxes of other planets?


1 Answer 1


The numbers are surprisingly difficult to find; the easiest-to-find overview in a somewhat funky paper though:

Body          duration [yr]   ref#
Mercury           550         6
Venus           29000         6
Earth           25600         6
Mars           173000         7
Jupiter        473500         8
Saturn        1800000         9
Uranus              1         5
Neptune       1870000         9

where their reference is

  1. R. Schmude, Uranus, Neptune, and Pluto and How to Observe Them, Springer, 2008, p. 32.
  2. V. Dehant and T. Van Hoolst, in Encyclopedia of the Solar System, edited by T. Spohn, D. Breuer, and T. Johnson, Elsevier, 2014, pp. 159–184.
  3. W. R. Ward, in Mars, edited by H. H. Kieffer, B. M. Jakosky, C. W. Snyder, M. S. Matthews, University of Arizona Press, 1992, pp. 298–320
  4. W. R. Ward and R. M. Canup, “The obliquity of Jupiter,” The Astrophysical Journal Letters, 640(1), L91, 2006.
  5. E. F. Milone and W. J. Wilson, Solar System Astrophysics: Planetary Atmospheres and the Outer Solar System, Springer, 2014, p. 489.

Those look reasonable, but I cannot check them myself at this time other than exemplarily. E.g. Ward and Hamilton (2004) also get similar values for Neptune and Saturn.

  • $\begingroup$ Formally, period of equinoctial precession of Mars is indeed 173 000 yr, or so. It however should be taken into account that the obliquity is not staying constant over this period. The obliquity is actually varying quite noticeably over the Milankovich cycle of 124 000 yr. So these two movements are superimposed, making the overall picture more complex. $\endgroup$ Aug 17, 2022 at 0:27
  • $\begingroup$ Is Uranus' precession really so extremely different than the others? That paper references page 32 of this book which I was able to see (yes, just that page) by watching an ad here: scribd.com/document/456201315/… It states: "Ring precession. The dashed line represents the line of the nodes and is the intersection between the equatorial plane of Uranus and the plane containing the epsilon ring. The line of the nodes makes one complete trip around Uranus in about 264 days. This movement is called precession." $\endgroup$ Dec 1, 2023 at 22:50
  • $\begingroup$ So 264/365.25 is clearly where they got that value for Uranus. So Uranus' overall precession is that value only if ring precession and planetary precession are the same, but I'm too much of a novice to confirm that. $\endgroup$ Dec 1, 2023 at 22:51
  • $\begingroup$ Found an inconsistency in the reference that says Uranus' precession is 0.7 years: a sentence in the text says, "The two points where the ring intersects Uranus's orbital plane are called nodes and these two points define the line of nodes." which contradicts the description of the figure (written in my previous comment) which says the line of nodes is from the "equatorial plane" instead of the "orbital plane". This quote is saying the Epsilon ring of Uranus precesses around Uranus at this rate, NOT that Uranus is precessing at that rate. $\endgroup$ Dec 2, 2023 at 14:58

You must log in to answer this question.

Not the answer you're looking for? Browse other questions tagged .