One of the most interesting aspects of Astronomy for me specifically is the element of spirituality or philosophy it tends to invoke. To witness the majesty and scale of universe evokes such wonder that, if you’ll allow some hyperbole, can at times be akin to a religious experience. I comment this not to say that such a feeling is even necessarily rational, but that it makes sense then that we humans would pay attention to the stars in our ancient days, and note one of the most interesting features of the sky: that our sun travels in a particular pattern through the sky, crossing through the same sets of stars on a consistent schedule, namely, the constellations of the (western) Zodiac. It is of little surprise that these took upon particular significance to our ancient kin, and continue to bear some similar significance to this day. As we undertook our studies this past week and learned about the sun’s relative “travels” through the stars, it made me wonder the precise origins of the Zodiac.
Astrology, or the practice of divination by way of the heavens, has been in practice since at least the beginning of the second millennium BC, and likely for long before. We have archaeological evidence of astrological practice within Mesopotamian society from around 1900 BC. Astrology was likewise developed in other cultures similarly far back, such as with Hindu astrology in the 1400s BC at the latest, and developed independently in China around 900 BC. The Zodiac emerged out of this general practice of Astrology, specifically in the context of Babylon. The Babylonians are the origin of the Zodiac we know today, splitting the groups of stars along the suns path into twelve distinct constellations, each with their own associated meaning, often correlated to one of their gods. This codification occurred around the 500s BC, though the exact time is of course unsure, and they used their system of twelve 30 degree arcs of the sky for time keeping, astronomical, and religious purposes. The Greeks then came along, under the conquering banner of Alexander the Great in the late 300s, and modified the existing Babylonian system to fit with their own religious system, by more or less replacing the names of the constellations. It is from the Greeks that the Zodiac spread throughout the Western world, and gave us the Zodiac we know today.
). To imagine torque, you can think of pushing open a door that has a spring hinge. You have to push pretty hard in order to open the door, and even then, the moment you let go the door swings back into its original position. Similarly, something (something with tremendous force) would have to turn the moon in order for its far side to face us, but it has a physical tendency to remain in the position it currently is in.
