Author: John F. Lindner

  • Hot & Cold Electricity

    John F. Lindner

    As I kid, I used to help my dad with electrical wiring projects (among other things). I learned that home electricity was “hot & cold”, like water in pipes — or at least, that’s how I understood the explanation. Later I learned that home electricity uses alternating current (AC) rather than direct current (DC), and…

  • Hamiltonian Flow

    John F. Lindner

    Newton wrote, “My brain never hurt more than in my studies of the moon [and Earth and Sun]”. Unsurprising sentiment, as the seemingly simple three-body problem is intrinsically intractable and practically unpredictable. … If chaos is a nonlinear “super power”, enabling deterministic dynamics to be practically unpredictable, then the Hamiltonian is a neural network “secret…

  • Summer Highlight

    John F. Lindner

    Since the mid 1990s, a highlight of my year has been the Physics Department’s National Science Foundation Research Experience for Undergraduates summer program. Our research assistants come from Wooster and from all over the United States, as detailed in the accompanying bubble chart (where the bubble diameters code number of participants per institution). To date,…

  • A Gigasecond at Wooster

    John F. Lindner

    A second ago, I posted this blog entry. A kilosecond ago, I wrote it. A megasecond ago, I isolated myself against the 2020 pandemic. A gigasecond ago, I began my career at The College of Wooster, which I celebrate today, 31.7 years later. Logarithmic timeline centered on the start of my first gigasecond at Wooster.

  • Higgs Without Molasses

    John F. Lindner

    Although almost all ordinary mass effectively arises from the kinetic and binding energy of quarks and gluons bound to protons and neutrons in atomic nuclei, the Higgs mechanism does endow some particles like quarks and weakons with intrinsic masses. Here I gently introduce the Higgs mechanism without using loose analogies like vacuum field viscosity. Stationary…

  • The Tall Towers

    John F. Lindner

    In 1945, science fiction author Arthur C. Clarke published “Extra-Terrestrial Relays – Can Rocket Stations Give Worldwide Radio Coverage?” in Wireless World magazine. Clarke calculated a special orbit, about 36 000 km above the equator with a period of one sidereal day, in which artificial satellites would appear to hover motionless above Earth. The satellites…

  • Losing Betelgeuse

    John F. Lindner

    At my computer Tuesday evening, I receive a message from a university physics chat that is both thrilling and chilling: LIGO + Virgo report a “burst” gravitational wave event, possibly due to a core-collapse supernova (or a binary collision where one object is in the hypothetical “mass gap” between black holes and neutron stars). The…

  • Continental Bridge

    John F. Lindner

    I remember looking at a classroom map of Earth and thinking the continents seem like puzzle pieces, especially north and south America in the west and Europe and Africa in the east. I mentally fit them together. Later I learned about continental drift and plate tectonics, driven by gravity and mantle convection, with newborn crust…

  • Table of Nuclides

    John F. Lindner

    As of 2019, we have identified or synthesized 118 distinct elements with Z protons, but about 2900 distinct nuclides with N neutrons (where atom is to element as nucleus is to nuclide). The start of my version of the table of nuclides is below, where number of protons Z increases toward 2 o’clock, number of…

  • Intrepid-Surveyor

    John F. Lindner

    Fifty years ago, Apollo 12 landed within sight of another spacecraft, a dramatic demonstration of pinpoint landing capability. While Dick Gordon orbited Luna in the command module Yankee Clipper, Pete Conrad and Al Bean left the lunar module Intrepid and walked over to the robotic Surveyor, which had landed over two years earlier. They retrieved…

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