In the movement of the December solstice Sun toward the “Galactic Alignment” A marks the position where the December solstice Sun was in relation to the Milky Way about 3,000 years ago; B is the location 1,500 years ago; and C marks the “2012 Window,” when the December solstice Sun has converged, as a result of the precession of the equinoxes, with the exact centerline of the Milky Way, or Galactic Equator.
The Earth’s rotation is not fixed in space, but wobbles like a rotating toy top, so that the axis falls backward through the fixed stars, 1° every seventy-two years.
This movement is called “precession.” Since the Sun is ½ ° wide, the winter solstice Sun takes thirty-six years to precess through the region of the Galactic Equator.
Actually, Belgian astronomer Jean Meeus (Mathematical Astronomy Morsels, 1997) determined that the precise alignment of the winter solstice point with the Galactic Equator occurred already in 1998. Why then do so many people speak of the alignment of the winter solstice with the Galactic Equator as taking place on December 21, 2012, the end date of the Maya calendar? Since it takes thirty-six years for the Sun to precess through the Galactic Equator, 1998 can be seen as the midpoint for a period that extends from 1980 until 2016. Instead of speaking of “2012” we should speak of the “2012 Window,” in the sense that the precise end date of the Maya calendar, on December 21, 2012, falls within this thirty-six-year period centered on the year 1998.
Though we may find ourselves initially disappointed that the date that we formerly believed to be so precise in its identification by the ancient Maya is actually a thirty-six-year time span, consider the enormous span of time between alignments: The alignment of a solstice or equinox point with the Galactic Equator occurs only each quarter processional cycle, that is, every 6,480 years. The next solstice alignment will take place in 12,960 years. That the Maya calendar, dating back perhaps further in time than our own Christian calendar, could pinpoint this rare, unique, astronomical event with such precision is stunning. Might there be other calendars with similar foresight?