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

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