Category Archives: Mathematics

Alien Suns Reversing in Exoplanet Skies

John F. Lindner May 19, 2022 10:07 AM

Not only can suns stand still in the sky, from some exoplanets their motion can apparently reverse! Wooster physics-math double majors Xinchen (Ariel) Xie ’21 and Hwan (Michelle) Bae ’19 and I just published an article elucidating these apparent solar reversals. Michelle … Continue reading →

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Slide Rule Examples

John F. Lindner April 14, 2022 11:30 AM

Slide rules were widely used in engineering, science, and mathematics until the early 1970s, including during the Gemini and Apollo space programs. Although rendered largely obsolete by the advent of inexpensive electronic calculators, their descendants continue to have specialized applications, such … Continue reading →

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Slide Rule Theory

John F. Lindner April 8, 2022 7:53 PM

Slide rules were the analog computers that ruled science and engineering for 400 years. Their brilliant innovation was using logarithms to convert multiplication and division to addition and subtraction, and Slide rules feature logarithmic scales that slide past each other. … Continue reading →

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4D Unknot

John F. Lindner October 6, 2021 11:10 AM

In four dimensions, you can’t tie your shoelaces — because 4D knots don’t work. Any 1D curve in 4D space can be continuously deformed to the unit circle, which is an unknot. The looping animation below demonstrates how to undo a … Continue reading →

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Dandelin Spheres

John F. Lindner September 6, 2021 9:11 PM

In 1609, Johannes Kepler first described how planets orbit the sun in ellipses. Kepler understood an ellipse as both the locus of points whose distances from two foci sum to a constant and as the intersection of a cone and a plane. But how … Continue reading →

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Spinors

John F. Lindner August 5, 2021 9:10 PM

Fermions like electrons, protons, and neutrons inhabit a 720° world: 360° rotations negate their quantum states, but 720° rotations restore them. A simple macroscopic model of such spinors is an arrow translating on a Möbius strip: as the center circle rotates, … Continue reading →

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Squares & Cubes

John F. Lindner July 27, 2021 5:05 PM

Marvelously, the square of the sum of natural numbers is the sum of their cubes! Equivalently, the sum of their cubes is the square of their sum. This mathematical gem is attributed to Nicomachus of Gerasa who lived almost 2000 years … Continue reading →

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Archimedes & Euler

John F. Lindner May 24, 2021 2:33 PM

A complex function that is its own derivative normalized to one at zero implicitly defines the famous Archimedean and Euler constants of circular motion and exponential growth. Even in a world of strong gravity, where the ratio of a circle’s circumference to its … Continue reading →

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Geographic Tongue

John F. Lindner March 3, 2021 3:03 PM

The improbable email was from a pre-dental math major asking about physics research projects combining math and dentistry, but my reaction was, “Yes — only at Wooster!”. Like animated tattoos, the surface patterns of benign migratory glossitis slowly move on the … Continue reading →

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Novel Math, Nobel Physics

John F. Lindner October 26, 2020 1:40 PM

When I was a kid I used to read Scientific American at the local library. I loved Martin Gardner‘s Mathematical Games column, and I vividly remember his description of Roger Penrose‘s then recent discovery of two shapes that force a … Continue reading →

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