Author Archives: John F. Lindner

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 readi… Continue reading →

The motion of one of the simplest dynamical systems, a torqued, damped, nonlinear pendulum, can be infinitely complicated. Consider a simple pendulum of length [latex]l[/latex] and mass [latex]m[/latex] rigidly connected to an axle of radius [latex]r[/… Continue reading →

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 &#82… Continue reading →

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… Continue reading →

One hundred years ago today, the Physical Review published Wooster graduate Arthur Compton‘s famous article on the scattering of light and electrons, which earned him a Physics Nobel Prize four years later. By relativistically conserving spacetim… Continue reading →

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

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 … Cont… Continue reading →

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 [latex]q^\prime[/latex] is at po… Continue reading →

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 comm… Continue reading →

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 → Continue reading →