that time (about 2,100 million years from now). See also Age of Aquarius Astrological age Astronomical nutation Axial tilt Euler angles Longitude of vernal equinox Milankovitch cycles Polar motion Sidereal year References Bibliography Dreyer, J. L. E. A History of Astronomy from Thales to Kepler. 2nd ed. New York: Dover, 1953. Evans, James. The History and Practice of Ancient Astronomy. New York: Oxford University Press, 1998. Explanatory supplement to the Astronomical ephemeris and the American ephemeris and nautical almanac Precession and the Obliquity of the Ecliptic has a comparison of values predicted by different theories Pannekoek, A. A History of Astronomy. New York: Dover, 1961. Parker, Richard A. "Egyptian Astronomy, Astrology, and Calendrical Reckoning." Dictionary of Scientific Biography 15:706–727. Rice, Michael (1997), Egypt's Legacy: The archetypes of Western civilization, 3000–30 BC, London and New York. Tompkins, Peter. Secrets of the Great Pyramid. With an appendix by Livio Catullo Stecchini. New York: Harper Colophon Books, 1971. Toomer, G. J. "Hipparchus." Dictionary of Scientific Biography. Vol. 15:207–224. New York: Charles Scribner's Sons, 1978. Toomer, G. J. Ptolemy's Almagest. London: Duckworth, 1984. Ulansey, David. The Origins of the Mithraic Mysteries: Cosmology and Salvation in the Ancient World. New York: Oxford University Press, 1989. External links D'Alembert and Euler's Debate on the Solution of the Precession of the Equinoxes Forced precession and nutation of Earth Precession Technical factors of astrology Celestial mechanics