Classic Understatement
You have to love astronomers. What with the vernal equinox happening tonight, I was reading about the precession of the equinoxes, which brought me to this…
Over longer time periods, that is, millions of years, it appears that precession is quasiperiodic at around 25,700 years, however, it will not remain so. According to Ward, when the distance of the Moon, which is continuously increasing from tidal effects, will have gone from the current 60.3 to approximately 66.5 Earth radii in about 1,500 million years, resonances from planetary effects will push precession to 49,000 years at first, and then, when the Moon reaches 68 Earth radii in about 2,000 million years, to 69,000 years. This will be associated with wild swings in the obliquity of the ecliptic as well. Ward, however, used the abnormally large modern value for tidal dissipation. Using the 620-million year average provided by tidal rhythmites of about half the modern value, these resonances will not be reached until about 3,000 and 4,000 million years, respectively. Long before that time (about 2,100 million years from now), due to the increasing luminosity of the Sun, however, the oceans of the Earth will have boiled away, which will alter tidal effects significantly.
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