The Complete Idiot's Guide to 2012 - Dr. Synthia Andrews Nd [40]
Codex Cues
Another way to calculate the Mayan year length is to take into account three items: the length of the Haab, the dates of the Long Count calendar, and the amount of time the Maya believed it took for the Earth to move through all the seasons. The result is that the Maya worked with a year length that is 365.242036. A bit more precise than the one the Gregorian calendar works with!
Eccentricity Cycle
The eccentricity cycle describes the changes in the earth’s orbit. The earth’s orbit around the sun is not a perfect circle; it’s an ellipse, or oval. This means that at one part of the orbit the earth is closer to the sun (called the perihelion); and at the opposite time in the cycle the earth is farther away from the sun (called the aphelion). When the earth is closer to the sun, temperatures will be warmer than when the earth is farthest away.
Here’s the catch: the elliptic orbit doesn’t always stay the same shape. It changes from being more circular to being more oval. When the orbit is more circular, the difference in temperature between the closest and farthest positions will be minimal, say 6 percent. When the orbit is more oval, the difference in temperature between the two positions is more extreme, jumping to 20 to 30 percent.
The length of the cycle, from most oval to most circular, is approximately 100,000 years. The variation in shape is caused by the speed the earth is traveling, and the pull of the sun, moon, and other planets on the earth’s gravitational field. So really, it displays the effects of celestial movement and interaction on the earth’s movements. As the Maya have said, the whole system is interactive!
Obliquity Cycle
Here’s another anomaly about the earth’s axis. It’s not straight up and down in relation to the path of the earth’s orbit around the sun. The earth’s axis is tilted. The tilt is what creates the seasons, and like everything else, it’s not always the same. The planet doesn’t always tilt to the same degree. During a 41,000-year cycle, the tilt of the earth’s axis changes from 22.1 to 24.5 degrees. The current tilt is 23.5 degrees. This means there is a greater difference between seasons now than when there was only a 22.1-degree tilt.
So what happens when the cycles coincide and the most extreme perihelion falls at the same time as the most extreme tilt of the planet? You got it: extremes of hot and cold. And yes, that may be a factor in the extremes of the end-time predictions of Chapters 11 and 12.
Precession of the Equinox
The precession of the equinox is one of the more dramatic cycles the Maya understood. It’s another result of the tilt of the earth’s axis. You already know that the earth turning on its axis creates night and day. It’s night for the side of the earth that’s not facing the sun and day for the side that is facing the sun.
If the earth’s spin were completely stable, every day would be the same length. But the earth does not spin on a stable axis. It wobbles. Consequently we have long days in the summer and short days in the winter.
Wobble
Spinning like a wobbling top, the axis of the earth scribes a small circle in the sky, called the precession. You can see what this looks like in the following illustration. As the earth spins, it travels along the edge of the circle it makes, changing the celestial landscape. In the time it takes to completely move around the circle, the earth moves through all the constellations in the sky. This not only changes what constellations we see at night, but also the stars and other celestial “background” features. In other words, the wobble is responsible for the movement of the constellations across the night sky.
So how long does it take the earth to turn a complete circle through all the constellations? The earth moves along the precession