PREDICTION: On December 21, 2012, when the Long Count calendar ends, a rare Galactic alignment of the Sun and the Milky Way will take place. This only happens once every 26,000 years.
FACT: On the solstice of December 21, 2012, the Sun, as seen from the Earth, will be crossing the plane of the Milky Way Galaxy near its center. This type of alignment of the path of the Sun with the plane of our Galaxy takes place every year; thus, it is not very special.
The alignment of the Sun with our Galaxy on the December solstice happens more rarely. This more rare alignment occurs during a 400 consecutive year period, and within every precession cycle of 25,772 years. This is thus somewhat more special. This image shows a planetarium view of the sky illustrating the Sun’s position on December 21, 2012, the date of the solstice. The image reflects what the sky will look like at noon on that day, at the latitude of Chichén Itzá, Yucatán, México. At midday, the Sun will be high in the sky, and projected against the Milky Way Galaxy. The Milky Way will not be visible behind the glare of the Sun of course, but the planetarium image is intended to demonstrate the alignment of the Sun with the band of the Milky Way Galaxy. There is some evidence in the archaeological record that the ancient Maya may have known about the astronomical phenomenon of precession. It is possible that the ancient Maya set the beginning of the Long Count, so that the 13-baktun cycle would complete on the December solstice of 2012. At this time, the Sun will be crossing the Milky Way, the road of the Maya ancestors in the sky.
Section content adapted from material provided by Dr. Bryan Mendez of UC Berkeley Space Sciences Laboratory. Published in Smithsonian e-magazine. http://maya.nmai.si.edu/2012-resetting-count/meaning-of-2012