Thanks Henrick. I would happily agree with the standard explanation as cited above but the moon will not allow it. The delta between the synodic and tropical lunar periodicities, show beyond a shadow of a doubt (pun intended) that the earth revolves around the sun almost exactly 360 degrees in a tropical year. This negates luni-solar precession theory, which requires the earth to come up about 50 arc seconds short of a full revolution in a tropical year (equinox to equinox). The luni-solar theory fails to account for a moving reference frame and this problem has occurred before:
In Ptolemy's day people thought the Sun orbited the Earth. Everyone could see the Sun rose in the East and set in the West, and no one could feel the Earth spin, therefore the only way to explain the Sun’s motion through the sky was to conclude the Sun itself went around the fixed Earth. Therefore, a missing motion (the Earth's spin) led to an incorrect conclusion.
Although this European belief held for almost a thousand years, the Moon never confirmed the incorrect motion of the Sun and Earth. Had one bothered to look carefully, they would notice the phases of the Moon were out of synch with the Moon’s revolutions around the Earth. The only way the Moon could go around Earth every 27.3 days, yet a new Moon could only be seen every 29.5 days, was if the Earth itself was curving around the Sun. This is proved with relatively simple rotation calculations but unfortunately, no westerner seemed to correlate the two facts for over a thousand years.
A similar misunderstanding; missing motion and failure to look at the lunar data, has led to another incorrect conclusion about the mechanics of our solar system. Specifically, the phenomenon known as “precession of the equinox” has been attributed to torque primarily from the Sun and the Moon, wobbling the Earth. The logic goes something like this: Everyone can see the Earth does not realign with the fixed stars at the time of the annual equinox, it is off by about 50.29 arc seconds per year. Copernicus said this is because the Earth “wobbles”, and Newton said that if it did wobble it must be due to the gravity of the Sun and the Moon acting upon the oblate Earth. The combination of these two principal forces is supposed to cause the pole to shift clockwise by the observable 50.29 arc seconds per year, meaning the equinox would arrive 50.29 arc seconds short of that point in the Earth’s orbit path that the equinox occurred at in the prior year. Because this is the observable, and there are no other theories, this “lunisolar” theory of precession has become widely accepted.
While the observable is true, lunar data shows the purported cause is not. Just as Ptolemy failed to consider another motion, the spinning Earth, and therefore came to the wrong conclusion when observing the Sun going around the Earth, so too are modern scientists forgetting to account for a motion. This time the missing motion is the solar system curving through space. With the solar system curving through space at about 50 arc seconds per year, and apparently some light torque upon the Earth, the solar system is gradually reorienting the Earth to inertial space (or precessing) at this rate. It is the motion of the solar system that causes the precession of the equinox, not lunisolar forces. Lunar rotation calculations help us understand this point:
If the Earth were coming up about 50 arc seconds short of the equinoctial point that it was at in the prior year, then lunar data would show the Earth goes around the Sun 50 arc seconds short of 360 degrees in an equinoctial year. But it does not show this. It shows that the Earth goes around the Sun 360 degrees in an equinoctial year. Yet anyone can see that the Earth in relation to the fixed stars appears to move around the Sun 360 degrees only in a sidereal year. Indeed, fixed star to fixed star has almost become the litmus test for what is or isn’t a 360 degree movement. But like Ptolemy’s Sun, that appears to orbit round the Earth, motions in space can be deceiving (if you don't account for moving frames).
Lunar calculations based on tropical data clearly show the Earth goes around the Sun 360 degrees in an equinoctial year. Interestingly, if one plugs in only sidereal data they also show the Earth moves 360 degrees relative to the fixed stars in a sidereal year, yet this orbit path of the Earth around the Sun takes 20 minutes longer and is 22,000 miles wider in circumference. Now obviously, the Earth does not have two different orbit paths around the Sun each year. So which is right? Mathematically, they are both correct; the Earth does move 360 degrees around the Sun in a solar year (relative to local objects) and does move 360 degrees relative to the fixed stars in a longer sidereal year. The only conclusion is, while the Earth is moving 360 degrees counterclockwise around the Sun in a solar year, the entire solar system (containing the Earth Sun reference frame) is moving clockwise relative to inertial space. The mathematical calculations support no other conclusion.
It is the missing motion of the solar system curving through space that modern scientists have failed to calculate in their lunisolar precession theory. But the Moon does not lie. Its movement is exact and acts like a witness to the Earth’s motion. The only way the Sun can appear to move around the Earth, and be confirmed by lunar data, is because the Earth is spinning on its axis. Likewise, the only way the Earth’s axis can appear to precess or wobble relative to inertial space, and not wobble relative to the Sun as confirmed by lunar data, is if the solar system (the reference frame that contains the Sun and Earth) is curving through space. Furthermore, the only way the solar system can be curving through space at a rate of 50 arc seconds per year, is if it were gravitationally affected by another very large mass...
Chinese Philosopher – Lao Tzu