Author Archives: John F. Lindner

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

While 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 hol… Continue reading →

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 descendant… Continue reading →

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, [latex display=”true”]\log xy = \log… Continue reading →

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 70 milliarcseconds. (For comparison, Earth’s moon subtends 31 arcmin… Continue reading →

Although a child of the Apollo program, I was gripped by Alfred Lansing‘s 1962 book Shackleton’s Valiant Voyage, which tells a great true story from the heroic age of Antarctic exploration. In the 1910s, shortly after Roald Amundsen and Rob… Continue reading →

The Webb telescope has 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 common center of … Continue readin… Continue reading →

A liquid-fueled rocket engine is a turbopump, plus some miscellaneous other stuff. Gas generator engines burn a little fuel to drive a turbine, which turns a centrifugal pump, which rapidly pushes the fuel and oxidizer propellants to the combustion cha… Continue reading →

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 read… Continue reading →

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 →