Alright, so we have an entire anime about heliocentrism. I have taught astronomy courses in the past and have a bit of interest in the history of science, so this is right up my alley. There were a couple things they brought up in this first episode that people might not be familiar with:
- Aristotle’s theory of gravity
Aristotle (4th century BCE) believed that everything had a natural place in the cosmos, and gravity was the force that pulled it to that place. In his worldview, earth’s natural place was at the center because it was the heaviest, water’s natural place was to sit on top of earth, air on top of water, fire on top of air, and then the celestial sphere above that with heavenly bodies like the moon embedded on that sphere.
This was a tool that dates all the way back to ancient Greece. The tool has many different uses (literally hundreds), but primarily was used in astronomy for precisely measuring one’s latitude, the elevation of an object in the sky, determining the time of day, measuring the height of objects, etc. It was a tool that was a go-to for any natural philosopher to have and ended up with many religious applications as well such as calculating eclipses, equinoxes, etc.
Believe it or not, this ancient Greek astronomer theorized the heliocentric model of the solar system a full ~1800 years before Copernicus would publish his work. Unfortunately his writings have been lost to time and we only have some small quotations and references to it that survive in later works. There were occasional astronomers that would come in the centuries following that would resurrect the heliocentric model, but it never reached enough of a critical mass to take hold of scientific consensus. The consensus until Copernicus was originally developed by…
Ptolemy was an ancient Greek thinker that proposed a model of the solar system that happened to support the theology of the newly forming Catholic church, which went on to promote the Ptolemy geocentric model and its epicycles as literal Gospel basically. In Ptolemy’s model, the Earth was at the center of the solar system and the other heavenly bodies (moon, planets, sun) moved in these complex loops that wrapped around in a circle while the distant stars were stuck on a celestial sphere encompassing everything that rotated. These complex epicycles were created to explain the occasional periods where planets would move backward in the sky relative to everything else, called retrograde motion. This is the model of the solar system that Rafal drew in the dirt near the end of the episode. Here is that same type of diagram from Wikipedia:
Science lesson over! I will echo @[email protected] in that one thing I didn’t enjoy about this episode was the torture scene that it started out with and then the later burning a heretic at the stake. So, not looking forward to more of that going forward. However, the scientist within me is burning (figuratively) to keep watching.
At least for this episode, the torture happened off screen…
We unfortunately lose our heliocentric sensei this episode, but not before he leaves us with some words of wisdom (@[email protected]):
I often say something similar to junior scientists I work with in the lab. I usually phrase it as a negative result is still a result. We can learn just as much (and often more) when things don’t work out the way we hope or expect them to than when they do. I remember back when the LHC was about to be turned on and some of my physics colleagues were really excited and hopeful for the standard model to fall apart once we started getting data back. Unfortunately, it still stands…
There were two additional science topics I wanted to bring up this episode. The first of which is a carryover from last episode:
This is the scale by which we measure how bright stars are. Rafal talked about how he is able to see stars with magnitude 6 and Hubert mentions how that must mean he has good eyes. This is because magnitude 6 is about as dim a star as you can see without any kind of light pollution or magnification. As a point of comparison, a magnitude 6 star is ~10,000 times dimmer than Mars or Jupiter in the night sky. That number doesn’t really give you a good intuition because our eyes don’t really work on a linear scale though, so magnitude uses a logarithmic scale. Mars/Jupiter are magnitude ~-3 (smaller numbers mean brighter). Another comparison would be Polaris, colloquially known as the North Star, which has a magnitude of ~2. For an illustration, wikipedia has one:
This is the star referenced in this episode and is the name given to the middle of the three stars that comprise the belt of Orion. I don’t have too much to add here other than that the three stars in the belt of Orion have served as a distinguishing feature in the night sky for many different cultures across history due to the relative brightness of all three and their close proximity. It is easy to pick out quickly to get your bearings. Also, as a bit of trivia for me personally, I have previously worked (in collaboration) with a company called Alnylam which derives its name from this star.