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.

GRAVITY and Gravity

In Alfonso Cuarón‘s Oscar-winning 2013 movie GRAVITY, actress Sandra Bullock‘s Dr. Ryan Stone makes an emergency entrance into an abruptly abandoned International Space Station. This month, European Space Agency astronaut Samantha Cristoforetti recreated this scene onboard the space station, as in … Continue reading

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Alien Suns Reversing in Exoplanet Skies

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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Black Hole Above the Fold

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

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Slide Rule Examples

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

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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Diffraction Limited

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

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Shackleton’s Valiant Voyage

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

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Halo Orbit

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 animation, a star (red) and planet (cyan) orbit their … Continue reading

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Merlin & Raptor

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

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Astronomy Christmas Gift

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

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