On the scientificity of string theory

I must emphasize that although I have a background in physics, by no means do I have expertise in particle physics or string theory. I was a condensed matter physicist, and an experimentalist not a theorist. I do not have any deep understanding of string theory beyond a general background knowledge. What I bring to the table is a bit of awareness of how physics research operates in practice, plus the cynicism that comes with the territory of being an ex-physicist.

String theory was essentially a scientific fad. I’m not going to go into the history, because I have no expertise on that, and the Wikipedia article is frankly opaque. Dr. Collier recently made a more accessible retrospective–although I find the video game irritating, and Dr. Collier is liable to get some things wrong.

The relevant part is that string theory was a fad in scientific research and a fad in popular science. The physicists were overly excited about it, and so was the public. Then there was backlash, which again occurred both among physicists, and in the public. String theory was criticized for failing to make any testable predictions. Peter Woit described the theory as “not even wrong” (and published a book with that title), because a theory could only earn the status of being wrong by making a prediction that was found to be false.

Today, long after all that went down, what I encourage among non-physicist readers is moderation. String theory isn’t exactly a success story, but in the end it’s still legitimate scientific research. Frankly, you probably shouldn’t have any opinion on string theory at all, and it was a mistake for science communicators to have ever encouraged you to have one.

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The Ant and the Universe

In my time as a puzzle enthusiast, one of the puzzles I encountered was called the ant and the rubber band. It was only later that I realized that this puzzle had some cosmic significance.

Problem Statement

We have an ant that is trying to crawl from one end of a rubber band to the other. But as the ant crawls, the rubber band also stretches out. The ant crawls one centimeter per second. The rubber band starts out one meter long, and stretches out one meter per second. This is one of those magical math rubber bands that can stretch indefinitely. Let’s just say the ant is mathemagical too. Will the ant ever reach the end?

At first glance, it looks bad for the ant. The ant crawls crawls one centimeter closer, but falls a whole meter back. So the ant is losing about 99 cm per second. That doesn’t sound like a path to victory.

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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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