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.

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 →

Posted in Astronomy, Mathematics, Physics | Leave a comment

Black Hole Above the Fold

John F. Lindner May 14, 2022 10:04 PM

When grocery shopping, I normally just glance at the newspapers in the newsstand. However, this morning, I was excited to see “above the fold” of the Wall Street Journal a large reproduction of the first image of the supermassive black hole … Continue reading →

Posted in Astronomy, Physics | Leave a comment

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 →

Posted in Astronomy, Mathematics, Physics, Students | Leave a comment

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 →

Posted in Mathematics | Leave a comment

Diffraction Limited

John F. Lindner March 17, 2022 11:41 AM

Yesterday, Webb optical telescope element manager Lee Feinberg said “We made the right telescope” while reporting that its focus has reached the  diffraction limit of 0.7 arcseconds at the infrared wavelength of 2 microns. (For comparison, from Earth, Luna subtends … Continue reading →

Posted in Astronomy, Physics, Space Exploration | Leave a comment

Shackleton’s Valiant Voyage

John F. Lindner March 9, 2022 2:53 PM

Although a child of the Apollo program, I was gripped by Alfred Lansing‘s 1962 book Shackleton’s Valiant Voyage, a great tale of endurance, leadership, and survival and an inspiring true story from the heroic age of Antarctic exploration. In the 1910s, shortly after … Continue reading →

Posted in Adventure | Leave a comment

Halo Orbit

John F. Lindner February 7, 2022 5:43 PM

The Webb telescope has fully deployed and arrived at its halo orbit about the second Earth-Sun Lagrange point. But how can it orbit an empty point in space? In the accompanying animated sequence of inertial space diagrams, a star (red) … Continue reading →

Posted in Astronomy, Physics, Space Exploration | Leave a comment

Merlin & Raptor

John F. Lindner January 1, 2022 10:21 PM

The turbopump is the heart of most liquid-fueled rocket engines. Gas generator engines tap off and burn a little propellant to drive a turbine, which turns a centrifugal pump, which rapidly pushes the fuel and oxidizer to the combustion chamber, after the cryogenic … Continue reading →

Posted in Space Exploration | Leave a comment

Astronomy Christmas Gift

John F. Lindner December 25, 2021 5:11 PM

I awoke early this Christmas morning to watch the successful launch of the James Webb Space Telescope. I remember the genesis of the telescope a quarter of a century ago when it was called the Next Generation Space Telescope. (The … Continue reading →

Posted in Astronomy, Space Exploration | Leave a comment

Burning Plasma

John F. Lindner December 9, 2021 3:20 PM

In August I received an urgent email from my brother with the title “Fusion”. The National Ignition Facility (NIF) had created a burning plasma — a star on Earth — a major milestone on the long road to controlled nuclear fusion. … Continue reading →

Posted in Physics | Leave a comment