Here's something I read in the last little while.
Shadow of the Seven Triangles
On the equinoxes, the Sun crosses a center point and makes an exact 90-degree angle directly over the Pyramid of Ku'Kulkan (El Castillo) at the sacred site of Chichen Itza on Mexico's Yucatan peninsula (a place that represents the turtle's head on the continent known as Turtle Island or North America).
The Castillo is part of the Mayan calander's Path of the Sun (solar calendar) with 4 stone stairways of 91 steps each plus an upper platform for a total of 365. The Maya had an 18-base for their mathematics and 18 months in a year. The pyramid has nine levels divided by the staircases or 18. The relationship of the Sun to the Earth at this sensitive point creates the phenomenon of the dramatic Shadow of the Seven Triangles, shadow triangles projected on the north staircase with serpent heads at the base. The triangles undulate in an ascending fashion in March and descend during the fall equinox.
Following 360-day Maya solar calendar are five "nameless days." The New Year started after this five-day period, a time unfit for work; a time for ceremony when the old world is symbolically destroyed and a new one created. These 5 days are considered unlucky days comparable to the time of chaos before creation and before world order was established. Ancient Egypt also commemorated these 5 days. Coincidentally(?), on the first of these five days both the Egyptian grain god, Osiris, and the Mayan grain god, Hun Hunahpu, were born.
The Sacred Tzolkin Calendar
In 1475, the Supreme Maya Council revealed the long-held vision of an ancient Solar Grandmother named X'Nuuk'K'in -- that a sacred calendar cycle of twice the Kal'Tun (260 years) must go by before the Solar Culture would flourish again.
In the Tzolkin calendar (260-day sacred year divided into 13 months of 20 days each), the Mayans intermeshed astronomical calculations of the solar year with that of the "synodical (synodical: the interval between two successive conjunctions of a planet with the sun) revolution" of Venus with a correction of four days every 61 Venus years; and, in addition, during every fifth cycle, a correction of eight days was made at the end of the 57th revolution.
The Fifth Sun
The current Mayan great-year cycle of 26,000-years, as well as the 104,000-year cycle (the fourth sun) closes on 4 Ahau 3 Kankin (Winter Solstice, December 23, 2012 C.E.) when we begin "El Quinto Sol" or the Fifth Sun. In this cycle, those who stay will become a cosmic humanity and contact with other worlds will be possible.
Disagreement of the Timing.
Scholars do not agree on the timing of these events. I will present the more popular ones so you can make up your own mind.
On March 21, 1995, this 520-year period was completed and the Age of Knowledge (Itza Age) began; a time when ancient and hidden knowledge is to be reawakened; a time when the condor of the south is to meet the eagle of the north and there will be a return of the Light of health, purity, wisdom, and healing on Earth. Via the magnetic grid of energy that envelops planet Earth and the many sensitive spots on the Earth often referred to as Sacred Sites, the elders said that the solar ceremonies in Chichen Itza in March, 1995, anchored the intent to activate humanity in the Light.
The Great Year
The Great Year is a 26,000 year cycle consisting of 12 ages, each 2,160 years long. The ages are determined by the poles of the earth and whatever constellation the north pole points to determines the age.
Cycles of time are the result of three movements of the Earth. The rotation around the Earth's axis causes day and night. Our yearly orbit around the sun brings the four seasons. The third movement comes as a result of the gravitational pull of the sun and moon which causes the earth to gyrate, shifting the poles at the rate of one degree every 72 years. The earth shifts so that in 26,000 years the north pole points to four different stars.
The Ecliptic
The Ecliptic is the Great Circle that describes the apparent path of the Sun around the Earth (but which is really the orbit of the Earth around the Sun. The Ecliptic extends approximately 8-9° of arc above and below (North and South of) the actual path of the Earth/Sun. The other planets in the solar system are always visible within this band of sky. The longitudinal (East-West) position of celestial bodies (i.e. planets, asteroids, etc.) is measured along the ecliptic.
Signs. The Signs are units of measurement each equal to 30 degrees of arc along the ecliptic.
Vernal Point. The point measured along the ecliptic which represents the apparent position of the Sun at the moment of the Vernal (Spring) Equinox. At the moment of the Spring Equinox, the Sun is directly overhead at mid-day along the Tropic of Cancer.
The Earth doesn't so much "shift" on its axis as it "wobbles" The Earth's axis is tilted at an angle of approximately 23.5° to the plane of the ecliptic. This tilt is what produces the seasonal variations. The Earth is also not a perfect sphere; it bulges in the middle near the Equator. This unequal distribution of mass causes the Earth to "wobble" around its rotational axis like a gyroscope. What this means is that the Earth's axis makes its own rotation, with the North and South Poles slowly describing a circle around the ecliptic pole (which is the pole exactly perpendicular to the plane of the ecliptic; the North and South poles, remember are tilted 23.5 degrees away from this plane). How slowly? Well, a complete cycle takes about 25,800 years. (26,920) The precession can also be seen in terms of the "North Star".
Currently the North Pole of the Earth is aligned with the fixed star Polaris. This was not the case 3,000 years ago; and by the year 14,000 A.D., the North Star will be Vega, not Polaris.
This rotation of the Earth's axis occurs at something like 1° every 71.5 years (about 5 seconds of arc per year). The "wobble" and the precession of the equinoxes were known to the Ancient Egyptians, although the first official "discovery" of it was made by an Ancient Greek astronomer, Hipparchus, who was born sometime around 190 B.C. It was noted because the Sun was in a slightly earlier position at the time of the Spring Equinox each year (as measured against the fixed stars). Because the movement slips backwards through the zodiac, it is called precession (as opposed to a forward-movement which would be called progression).
Now 1° every 71.5 years doesn't sound like too much, but it certainly adds up over 2,000 years or so.