Rambam- Understanding the Spheres (Celestial Bodies and Their Orbits)- Yisodei Hatorah perek 3 halacha 1

The Rambam's approach to Judaism is that of a rationalist. He attempts to explain and understand everything based on science and nature. The only problem with this is that in his time, science and nature were not understood in the same way we know it today. Their understanding of how the celestial bodies moved and rotated is not the same as we know it today. However, this lack of scientific knowledge does not in any way detract from his ideas on Judaism. Every generation, according to the Rambam, needs to use the science that they know to rationalize their understanding of G-D. As Rambam understood science and tried to rationalize G-D's existence through that scientific knowledge, so too must we use the science available to us and rationalize the existence of G-D. In this perek he discusses the celestial bodies. He says,


הגלגלים הם הנקראים שמים ורקיע וזבול וערבות. והם תשעה גלגלים. גלגל הקרוב ממנו הוא גלגל הירח. והשני שלמעלה ממנו הוא גלגל שבו הכוכב הנקרא כוכב. וגלגל שלישי שלמעלה ממנו שבו נוגה. וגלגל רביעי שבו חמה. וגלגל חמישי שבו מאדים. וגלגל ששי שבו כוכב צדק. וגלגל שביעי שבו שבתי. וגלגל שמיני שבו שאר כל הכוכבים שנראים ברקיע. וגלגל תשיעי הוא גלגל החוזר בכל יום מן המזרח למערב והוא המקיף ומסבב את הכל. וזה שתראה כל הכוכבים כאילו הם כולם בגלגל אחד ואף על פי שיש בהן זה למעלה מזה. מפני שהגלגלים טהורים וזכים כזכוכית וכספיר לפיכך נראים הכוכבים שבגלגל השמיני מתחת גלגל הראשון:


"The Spheres, they are called Heaven (Shamayim), Expanse (Rakia), Residence (Zevul) and Mixing (Araba). There are nine Spheres in total. The closest Sphere to us is the Sphere of the moon. The Sphere after that is the Sphere that has within it a body which is called Mercury. The third has within it Venus. The fourth has within it the Sun. The fifth has within it Mars. The sixth has within it the body of Jupiter. The seventh has within it Saturn. The eighth Sphere has within it all the other bodies that appear in the expanse. The ninth Sphere is the Sphere that returns,every day, from the east to the west. This is the Sphere that surrounds everything and causes everything to rotate.


The fact that a person sees all the celestial bodies as if they are all in one Sphere, even though they are arranged one higher than the other, is because the Spheres are pure and transparent like glass and sapphire. Therefore, we see the bodies that are in the eighth Sphere as if they are lower[, closer to us,] than the bodies in the first Sphere."

The one important point that I want to focus on here is the four different names that the Rambam gives to the Spheres. If there are nine Spheres then why does the Rambam say there are only four names, what about the other five Spheres? I think the answer is as follows. The Rambam believes that there are nine Spheres in total, but some of the Spheres are in the same general category.

The Heaven category includes the Sphere of the Moon since this is the Sphere that is right above our sky and with which we can most closest relate. Then there is the category of the Expanse, this includes the bodies of Mercury, Venus, the Sun, Mars, Jupiter and Saturn. This category encompasses all the Spheres that cause the bodies inside these Spheres to rotate. The next category is that of the Residence. This category contains within it the eighth Sphere which is the Sphere that contains all the other celestial bodies that are so far away that we can't even relate to them. The final category is that of Mixing. This category contains the ninth Sphere which is the force that moves all other Spheres.

The first category, Heaven, is the category that most relates to humans. This is experienced through the calender, which we base on the moon. Also, this is why every month we do the blessing on the Moon. The next level is that of the second category, Expanse. The Expanse has the Spheres that man relates to, but on a much more distant level. This is why we bless the sun, but only once every 28 years. Also, we relate to the other bodies in our solar system, but on a much more distant level. The third level is that which we can not relate to, but there is something physical that we can see. This is the category of Residence. The Residence is the Sphere where celestial bodies that can relate to G-D because of their distance from man, but can't relate to G-D because they are visible, which makes them physical on some level. The final category, of Mixing, refers to the Sphere that causes all Spheres to rotate. This is the final level before G-D. This is because this Sphere is completely removed from physicality except that it has a relation to the physical Spheres because it causes them to rotate directly. G-D causes everything to rotate indirectly, but this Sphere is the direct cause of the rotation of these other Spheres. It is similar to how the Chayos cause the Ophanim to come into existence.