February 28, 2013

Ancient astronomy

The above image is the first slide that I use to introduce the topic of ancient astronomy in my introductory astronomy course. It's something I put together a few years ago, and although I still sort of like it, I have a hard time remembering exactly what all the thumbnails are supposed to be representing.  As best as I can remember, the points I was trying to illustrate when I first put this slide together were:

1.) Many cultures around the world had at least rudimentary knowledge of the night sky, and in many cases had knowledge of astronomical alignments related to the calendar.

2.) We don't have time in class to talk about all of the interesting things that these cultures knew about. There is a LOT of interesting material that we could go into, but in the interest of getting to some modern astronomy topics, we have to pick and choose some ancient astronomy topics and leave the rest mostly untouched.  That's not to say that non-Western cultures did not know about or explore the cosmos.

From left to right in the above image, then:

The pyramid is El Castillo, also known as the Temple of Kukulkan located at Chichen Itza (not Chicken Pizza, as my tour guide told me when I went there a few years ago).  The temple is aligned such that on the equinoxes the sun casts a shadow over the steps of the pyramids which connects to the heads of serpents carved into the base of the steps. It's a pretty neat effect, and shows the Mesoamericans knew when the equinox would arrive and how to align the structure to accomplish the effect.  The Chichen Itza site also has what is thought to be an astronomical observatory on it. The tour I went on did not allow for a very close approach to the building, nor did the guide we have know much about that particular structure.

The middle image is (I THINK) a photo of the ruins of Babylon.  I do not believe that the particular image had any astronomical significance. Rather, I think I was trying to point out that many cultures in the middle east (Babylonians, Sumerians, Assyrians) at least attempted to understand the night sky. Clearly, I am not a historian, anthropologist, or archeology expert. I would like to know more about the ancient astronomical knowledge of the middle east.

On the right is a photo of a an armillary sphere at the Purple Mountain Observatory in China. This type of sphere was used by ancient astronomers to measure the position of stars in the night sky. What is not clear from the article that I linked to is whether or not the pictured instrument is an original or a replica.  I seem to recall that the armillary sphere at the Purple Mountain Observatory is actually a replica of the ancient instrument. I think that the replica is itself relatively old, but again, it's not clear from the page I linked to.

Maybe in the future I can dig up the original references I was using to piece together this slide.  For now, I'm happy with what I have.

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