BİRİNCİ FEN · ÜÇÜNCÜ BÂB · DOKUZUNCU FASIL · Dördüncü Madde
This passage details the Earth's axial tilt and its effect on seasons and day/night cycles, drawing upon astronomical observations and presenting a cosmological model.
The fourth article states that the Earth’s axis is parallel to the orbit of the annual path and aligned with its poles, which causes differences in daylight hours and the changing of the four seasons.
Beloved! It must be known that new astronomers have said: The Earth's axis is placed parallel to its annual orbit, namely to the axis of the world (the ecliptic), and its poles are aligned with the poles of that orbit. The equator, which is in the position of the Earth’s belt, is located south and north of the surface of the annual orbit. For if the Earth's axis were parallel to the axis of its own circle like the axis of the signs (zodiac), then climates would not progress so regularly, and it would never be possible for the change and succession of the four seasons to occur in any place or time. Rather, it is known that the Earth’s orbit’s axis deviates twenty-three and a half degrees from the world's axis like the axis of the signs of the zodiac and inclines towards the surface of the annual orbit, forming an angle of sixty-and-a-half degrees with this movement. [552] For it is observed that the Earth constantly changes by turning toward the felt (perceived) side belonging to the sphere of the signs while maintaining its alignment towards the world’s axis, which is presumed to exist. In this state, as long as the Earth continues its annual motion revolving around the sun, the changes of the four seasons continue to occur at specific times, changing with one departing and another arriving – this has been confirmed by experience.
It is assumed that what is described above is arranged in sequence on a plane, so that the fixed sphere (b, j, d, y) is the Earth’s annual orbit (w, k, a, h), and the sun is placed exactly in the middle of these imagined entities. For example, when it is summer, meaning when the Earth is aligned with the sign of Capricorn and the sun is seen in its opposite position, the sign of Cancer, if the Earth were placed at the “k” point, then the line of the Earth’s axis (“sin, mim”) would be observed to be parallel to the world's axis. It deviates twenty-three and a half degrees from the axis of the signs of the zodiac and is inclined at an angle of sixty-and-a-half degrees towards the surface of the Earth's annual orbit – which is in the vicinity of the “w, k, h” angle. In this way, it is seen that the sun’s rays reach the Earth perpendicularly. That is, a ray emanating from the center of the sun to the center of the Earth reaches the surface of the Earth, not to the Earth's equator circle, but at an angle of twenty-three and a half degrees from the Cancer tropic, passing through the equatorial circle and receding towards the north pole, as it is known. For this reason, when the sun, the lamp of the world, illuminates the northern hemisphere completely and appears in the northern signs, it is observed to be one degree away from the south pole.
Subsequently, when the Earth reaches the “a” point at the beginning of autumn, it is assumed that the line of the Earth’s axis (“sin, mim”) is located parallel to itself and to the world's axis. At this time, as the Earth is aligned with the beginning of the sign of Aries and the sun appears directly opposite it in the sign of Libra, it is determined that rays emanating from the center of the sun reach the Earth’s axis perpendicularly. For these rays are observed to reach the surface of the Earth at the point where the equator circle begins the sign of Libra, and it is known that they spread equally on either side of the two poles.
When winter begins and the Earth reaches the “h” point, the alignment of the “sin, mim” axis remains in its previous state, and the sun’s rays reach the surface of the earth perpendicularly from the position of the Capricorn tropic. In this case, it is observed that the southern hemisphere of the Earth is completely illuminated and one degree leaves the north pole.
At the beginning of spring, when the Earth reaches its own point with its annual orbital movement, namely when it reaches the beginning of the sign of Libra, the sun appears at that time in the sign of Aries.
Therefore, it is known that rays emanating from the center of the sun to the center of the Earth reach the surface of the Earth at the point where the equator circle begins the sign of Aries. In this way, it is known that these rays are spread equally on either side of the two poles. However, at this time, the portion of the Earth that is illuminated towards the sun is not visible to us because we are located outside the drawn shapes. According to new astronomy, the succession and lengthening of day and night, the successive changes of the four seasons, their differences, and the fact that day and night last approximately six months at both poles – all this is known through this method.
The most correct knowledge is only with Allah, the Exalted.