The Motions That Appear Around the Sun

The Earth is carried along by three different motions.

1. Annual Revolution:

The first motion occurs in a great orbit, in which the Earth revolves around the Sun following the succession of the zodiac signs, completing a full cycle in one year, always traversing equal arcs in equal periods of time. The center of this orbit is displaced from the center of the Sun by 1/25 of its radius. Since the radius of this orbit is imperceptible in comparison to the height of the firmament, it follows that the Sun appears to move as if the Earth were positioned at the center of the universe. However, this apparent motion of the Sun is actually due to the movement of the Earth. For example, when the Earth is positioned under Capricorn, the Sun appears, by direct alignment through the diameter of the orbit, in Cancer, and so on. Due to this motion, the Sun appears to move unevenly according to its distance from the center of the orbit, as previously mentioned. The maximum variation resulting from this is about 2 degrees and one-sixth. Additionally, the Sun shifts from the center of its orbit towards a point in the firmament about 10 degrees west of the bright star in the head of Gemini. The Sun is observed at its highest altitude when the Earth is at the opposite point of its orbit, with the center of the orbit positioned between them. Not only the Earth but everything within the lunar sphere is carried along by this great orbit.

2. Daily Rotation:

The second motion of the Earth is its daily rotation, which is its most intrinsic motion. This occurs around its poles in the order of the zodiac signs, that is, from west to east. Due to this motion, the entire universe appears to whirl around in a rapid vortex. In reality, it is the Earth, along with its surrounding waters and adjacent air, that rotates.

3. Axial Inclination:

The third motion is the inclination of the Earth’s axis. The axis of the daily rotation is not perfectly parallel to the axis of the great orbit but is tilted by a certain amount. In our era, this tilt is about 23.5 degrees. While the center of the Earth remains on the ecliptic plane (that is, along the circumference of the great orbit), its poles trace small circles around points that are equidistant from the axis of the great orbit. This motion also completes nearly one revolution per year, making it almost comparable to the great orbit. However, the axis of the great orbit maintains a fixed orientation relative to the firmament, always aligned with what are known as the poles of the ecliptic. If the motion of inclination were perfectly synchronized with the great orbit, the poles of daily rotation would remain in the same celestial position at all times. However, over long periods, it has been observed that the Earth’s orientation relative to the celestial sphere changes. Because of this, some have believed that the firmament itself undergoes motion, though the exact nature of this motion has not yet been fully determined. Nevertheless, the idea that all these effects result from the motion of the Earth rather than the heavens seems less surprising.

As for which celestial body the Earth’s poles align with, that is not my concern here. However, I observe that even in common objects, a piece of iron rubbed with a magnet always tends to align with a specific direction in the world. Nevertheless, the more plausible theory is that the poles move according to a certain orbital motion, which must undoubtedly occur beneath the Moon.