Author Archives: John F. Lindner

About John F. Lindner

John F. Lindner was born in Sleepy Hollow, New York, and educated at the University of Vermont and Caltech. He is an emeritus professor of physics and astronomy at The College of Wooster and a visiting professor at North Carolina State University. He has enjoyed multiple yearlong sabbaticals at Georgia Tech, University of Portland, University of Hawai'i, and NCSU. His research interests include nonlinear dynamics, celestial mechanics, and neural networks.

The Ringed Planets

John F. Lindner July 1, 2023 6:43 PM

When I was a kid, Saturn was the ringed planet. But today, we know that all of the outer planets have rings. The James Webb Space Telescope has now imaged each of them in infrared revealing their distinctive structures, including … Continue reading →

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Simplest Chaos

John F. Lindner June 25, 2023 7:26 PM

The motion of one of the simplest dynamical systems, a torqued, damped, nonlinear pendulum, can be infinitely complicated. Consider a simple pendulum of length and mass rigidly connected to an axle of radius wrapped by a rope that hangs down … Continue reading →

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Vampire Ein Stein

John F. Lindner June 2, 2023 10:39 PM

Just a couple of months after announcing the remarkable discovery of a single shape that forces a non-periodic tiling of the plane, Smith, Myers, Kaplan, and Goodman-Strauss have announced an improved aperiodic monotile or ein stein. (Ein stein is “one stone” … Continue reading →

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The Temperature of the Vacuum

John F. Lindner May 18, 2023 4:47 PM

Quantum field theory predicts that the temperature of empty space should depend on the observer’s motion, increasing proportionally with acceleration. Here I attempt an accessible introduction to this striking effect, related to Hawking radiation and discovered independently by Fulling, Davies, … Continue reading →

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A Century of Compton Scattering

John F. Lindner May 1, 2023 8:46 PM

One hundred years ago today the Physical Review published research on light scattering electrons that would earn its author, Wooster graduate Arthur Compton, a Physics Nobel Prize. By relativistically conserving spacetime momentum, as in the diagram below, and treating light … Continue reading →

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We Are Going

John F. Lindner April 29, 2023 9:08 PM

After half a century confined to low-Earth orbit, and as soon as late next year, humans will once again leave Earth and voyage to Moon. The reality of this exciting adventure crystallized earlier this month when NASA announced the diverse … Continue reading →

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Behold, an Ein Stein!

John F. Lindner March 29, 2023 5:30 PM

This academic year has been thrilling: first nuclear fusion breakeven, now an ein stein! Last week, a preprint at arxiv.org by David Smith et al. announced an “ein stein”, or one stone, a shape that forces a non periodic tiling … Continue reading →

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Generalizing Coulomb’s Law

John F. Lindner March 6, 2023 4:47 PM

The forces between two electric charges in arbitrary motion are complicated by velocity, acceleration, and time-delay effects. The forces need not even lie along the line joining the two charges! Suppose a source charge is at position with velocity and … Continue reading →

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Triple EVA

John F. Lindner February 16, 2023 11:15 PM

Since the mid 1960s, all space walks or extra-vehicular activities (EVAs) have involved just one or two astronauts — except once. In May 1992, on the STS-49 mission, the crew of the space shuttle Endeavour was attempting to rescue a stranded communications … Continue reading →

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5-Color Theorem

John F. Lindner February 5, 2023 1:48 PM

On 1852 October 23, Francis Guthrie noticed that he needed only 4 colors to color the counties of England so no two bordering counties shared the same color. This works for any map, but only in 1976, and with the aid of … Continue reading →

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