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Into the Wind
Last month, on 2016 April 18, a SpaceX Falcon 9 launch vehicle delivered a Dragon cargo capsule to the International Space Station and successfully landed its 48-m first-stage booster on the drone ship Of Course I Still Love You in the Atlantic ocean. SpaceX intends to reuse such stages and perfect rocket landings on…
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Dreaming Eyes Wide Open
1968. White Plains, New York. My mother takes me to a matinee of 2001: A Space Odyssey. The theater seats thousands and the movie plays continuously all day without commercials or trailers. A uniformed usher with a flashlight seats us. I stare wide-eyed, mesmerized by the images and sounds. I ask my mother what the…
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Kelly Twin Paradox
Yesterday astronaut Scott Kelly returned from nearly a year in free fall aboard the International Space Station to join his identical twin brother Mark back on Earth. Due to their different spacetime paths, I estimate that Scott aged about 9 ms less than his brother, and therefore travelled about 9 ms into the future, becoming one of…
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A New Kind of Astronomy
One of the first things I did as a grad student in 1982 was tour the Laser Interferometer Gravitational Wave Observatory (LIGO) prototype on the Caltech campus about a block from my dorm. It was housed in a utilitarian L-shaped building wrapped around the corner of another building. I toyed with the idea of working…
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Hillary & Armstrong
You’re probably familiar with the iconic photograph of Edmund Hillary standing atop Earth’s highest mountain wearing an oxygen mask in air so thin the sky is almost black as space — but apparently Hillary declined to be photographed and instead this photograph is by Hillary of his companion Tenzing Norgay during 1953’s first successful ascent of…
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Ticktock Deadbeat Escapement
The escapement is one of history’s greatest inventions; it enables a collection of wood or metal to tell time. The animation below illustrates a pendulum clock’s deadbeat escapement, apparently introduced by Richard Townseley, Thomas Tompion, and George Graham in the late 1600s and early 1700s. The escapement wheel transfers energy to the pendulum to overcome…
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The Falcon Has Landed
Monday evening, the first of SpaceX’s 70 m (or 230 ft) Falcon 9 full thrust launch vehicles successfully deployed 11 satellites to low Earth orbit — and performed reversal, supersonic retrograde, and landing burns to return the first stage to Cape Canaveral. Recent upgrades to the Falcon 9 include densified oxidizer and fuel, with liquid oxygen…
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ER = EPR?
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…
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The Martian
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…
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19th Century Foreground, 20th Century Background
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,…
Thanks, Mark! I enjoy reading your posts as well.