Paper: The statistical mechanics of music

Today I will discuss:

“The structure of musical harmony as an ordered phase of sound: A statistical mechanics approach to music theory” by Jesse Berezovsky in Science Advances (2019). Publicly accessible

I don’t remember where I found this paper, but at some point I wrote it on the back of my hand, so to speak, and it sounds intriguing. This paper uses statistical physics methods to try to explain music. In particular, it’s interested in explaining tuning systems, especially 12 equal divisions of the octave (12edo), as a way of minimizing dissonance while maximizing musical possibility.

Initially I’m quite skeptical, and you should be too. If I were more familiar with world music traditions, I’m sure could point out several traditions that violate this paper’s assumptions, including traditions that don’t use 12edo, and traditions that aren’t clearly trying to minimize dissonance. Even in western musical systems, there’s quite a lot of emphasis on the dissonant major 7th, which calls into question how much minimizing dissonance is really the goal. Nonetheless, it seems an interesting exercise to see how much we can predict from these assumptions, and if the predictions don’t match reality we can later back up and consider where it went wrong.

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Origami: James Webb Space Telescope

Last month I heard a lot of buzz about the James Webb Space Telescope. So I made origami of it.

origami of the James Webb Space Telescope mirrors

James Webb Telescope, designed by Robert J. Lang. Folding template online.

Specifically, this is just the big mirror component of the James Webb Space Telescope (JWST).

Since people are currently interested in the JWST, and since I just made origami of it, and since I have a physics background, I thought I’d talk about it. Or at least, explain why the mirrors look that way.

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Answering physics FAQs without preparation

Experts don’t know everything. Often, they only know how to look things up, and how to understand what they find. If you’ve ever seen physicists answering a physics FAQ, those answers took a lot of effort to get right. Some common questions are in fact really complicated, or hard, or maybe they just aren’t about the things that physicists normally think about.

With humorous intent, I’m going to answer a bunch of frequently asked questions, sampled from this physics FAQ by John Baez. And I’m doing it without preparation, so the answers will be bad.

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The physics of jigsaw puzzles

Wholesome jigsaw puzzle youtuber Karen Kavett recently did a challenge where she assembled a 1000 piece puzzle by selecting 100 pieces at random at a time. For a while, this just looked like a bunch of scattered pieces with only a few connections. But once she had 700 or 800 pieces, the whole puzzle started to come together, despite the gaps.

I found this fascinating, because it is a live demonstration of a concept in physics/math: the percolative transition. This is something I often think about when assembling puzzles.

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The speed of light in different directions

As a reminder, I’m open to requests to discuss any popular physics articles or videos, to append to my “I read popular physics” series. This video was not requested, but was shared by a friend of a friend a while back, and I have things to say about it.

Recently, the YouTube Channel Veritasium posted a video “Why the Speed of Light* Can’t be Measured”. The video argues that all measurements of the speed of light involve sending light in one direction, and waiting for it to come back. However, the light could theoretically be traveling faster in one direction than the other. It seems we are not directly measuring the speed of light, but rather the average speed of light in both directions. The constant speed of light in all directions is a matter of theoretical convention rather than empirical fact.

In the Facebook thread where I first saw the video shared, many people were incredulous. As for myself, I immediately understood the argument from the title, and immediately agreed that it was correct. However, I feel the video is misleading, as it does not explain why there is a theoretical convention that the speed of light is constant. And by doing so, I feel it misses the point of relativity theory.

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A year of reading popular physics

At the beginning of 2020, I received a one-year subscription to Scientific American. I embarked on a blogging series in which I read articles about physics, and offer my commentary as a person with a PhD in physics. I may continue this series in 2021, but instead of reading articles in Scientific American, I’ll take reader requests. Just send me any articles or videos that you’d like me to discuss or explain. Requests must obey the following restrictions:

  • It must be intended for popular audiences, as opposed to scholarly audiences.
  • It must be about physics or adjacent to physics. I will also consider requests for math-related articles.
  • I must have access to the article or video. Note, I still have a Scientific American subscription, so those are fair game.

New or old articles are welcome, and videos too.  I will exercise my own discretion among qualifying requests, taking into consideration how much time it would take me to process, and how interesting I think it would be to write about.  To make a request, leave a comment or e-mail me at skepticsplay@gmail.com.

Below the fold, I have my review of the articles I’ve written about so far.

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I read popular physics: Explosions at the edge

This is part of my series where I read physics articles in Scientific American, and rant about barely related tangents in order to provide “context”.

After the November issue, which didn’t really have any physics articles at all, the December issue has two major articles! One is astronomy, the other one is about the fusion reactor, ITER. But, after complaining about how all the physics articles are about astronomy, it looks like I’m still choosing the astronomy article. The ITER article is just a bunch of photos of the engineering, and I don’t have much to say about that.

So, the astronomy article is “Explosions at the Edge” (or that’s how it’s titled in print). It’s about the surprisingly diverse ways that massive stars can go supernova. For example, rather than simply exploding, a star may first shed a layer of gas, and then the subsequent explosion will collide with that gas, producing a prodigious burst of light.

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