Author: John F. Lindner

  • ER = EPR?

    John F. Lindner

    This month is the 100th anniversary of Albert Einstein’s November 1915 discovery of the gravitational field equations of General Relativity, in which test masses move along the straightest possible paths (called geodesics) in spacetime curved by the density and flux of energy and momentum (including mass and pressure). General Relativity allows spacetime to be topologically…

  • The Martian

    John F. Lindner

    Ridley Scott’s The Martian (2015) is the best Mars movie I have yet seen. Genuinely faithful to Andy Weir’s popular novel, The Martian chronicles astronaut Mark Whatney’s struggle to survive on Mars, after being accidentally stranded there, and the efforts by NASA and Whatney’s crew to rescue him. The story emphasizes the problem-solving character and…

  • 19th Century Foreground, 20th Century Background

    John F. Lindner

    Although some early aviation aficionados allege other flights (or hops) preceding the Wright brothers’ experiments at Kitty Hawk on 1903 December 17, the Wright Flyer did fly four times that day, including a final flight nearly one minute long, with the Wrights famously photo documenting their progress. They never flew that first aircraft again. Instead,…

  • On the Shore of the Arctic Ocean

    John F. Lindner

    It was a privilege to spend the 2014-2015 academic year and summer on sabbatical at the University of Hawai’i in Honolulu. During the last week of July, I stood on the spectacular beach at Kailua near sunset and said to myself “wow, wow, wow”. A week later, on my way home, I stood on the…

  • Rubik’s Cube Puzzles

    John F. Lindner

    As a kid, I enjoyed solving the “15 puzzle”, a sliding puzzle consisting of a 4×4 grid of 15 squares. However, I was amazed by a kind of 3D analogue of the 15 puzzle: Ernö Rubik’s 1974 masterpiece, which is both a seemingly impossible mechanism (how does it not fall apart?) and a silent challenge (one…

  • It’s Geology, But Not As We Know It

    John F. Lindner

    In a famous Star Trek misquotation, Mr. Spock says to Captain Kirk, “It’s life, Jim, but not as we know it”. Well, yesterday the New Horizons spacecraft returned its first closeup of Pluto, and it’s geology, but not as we know it. The Tombaugh region of Pluto contains a craterless expanse dotted with two-mile high…

  • The Double Planet

    John F. Lindner

    Next week the New Horizons spacecraft falls through (or “flies by”) the Pluto-Charon binary system. This week New Horizons photos reveal dramatic differences between Pluto and Charon, despite their presumed common origin in an interplanetary collision. (By the way, some astronomers — and apparently the New Horizons science team — pronounce “Charon” more like “Charlene”,…

  • Chaos in the Clockwork

    John F. Lindner

    The work of Newton and Laplace suggested to many that the solar system was like a giant clockwork, which was illustrated by beautiful mechanical models called orreries. The controversial Molchanov hypothesis avers that every oscillatory system evolves to a resonance governed by a family of integers, like the 3/2 resonance between the orbits of Pluto…

  • The Flight of the Dragon

    John F. Lindner

    Last week, SpaceX conducted a successful pad abort test of its innovative Crew Dragon spacecraft. Powered by hypergolic monomethylhydrazine CH3(NH)NH2 fuel and nitrogen tetroxide N2O2 oxidizer, which ignite on contact, the Super Draco engines accelerated Dragon from 0 to 100 mph in 1.2 seconds — that’s faster than a Tesla (the electric cars made by Elon Musk’s…

  • The Unveiling of Pluto

    John F. Lindner

    As a kid, I poured over diagrams in Popular Science magazine describing possible Grand Tours of the outer solar system (Jupiter, Saturn, Uranus, Neptune, and Pluto) made possible by a rare alignment of the planets. Unfortunately, budget cuts reduced the Grand Tour to the Voyager missions to Jupiter and Saturn. While Voyager 2’s mission was ultimately…

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