« August 6, 2021 | Main | August 8, 2021 »
August 7, 2021 Archives
Saturday, August 7, 2021
CONTEXT: Chaotic Bouncing Balls and Concave Billiards
Posted at
14:40
THE HAPPENING WORLD: University of Wisconsin Removes Giant Rock Due to Nickname in 1925 Newspaper Headline
"70-ton rock … taken off-campus following an initiative last June by the Wisconsin Black Student Union and Wunk Sheek to remove it because a nickname given to the boulder is a racial slur." wow https://t.co/S0mJf3WxiH
— Robin Hanson (@robinhanson) August 7, 2021
Behold another to file under “AGE OF STUPID”. Here is an article with more details, including information about the 1925 newspaper article and nickname. The rock, with a mass of 42 tons, is a pre-Cambrian “glacial erratic” carried by glaciers during an ice age and deposited after they receded, is estimated to be more than two billion years old. It was officially named “Chamberlin Rock”, in honour of Thomas Chamberlin, a geologist who was president of the university from 1887 through 1892.
Posted at
14:03
TRACKING WITH CLOSEUPS: Observing Transits of Earth from other Stars
Observing transits, where planets pass in front of the stars they orbit, has become the means by which most exoplanets (planets orbiting other stars) have been discovered. Precision measurements allow detecting the diameter, possible moons, and atmospheric properties of these planets. Future instruments may make it possible to identify signs of life, such as the presence of atmospheric gases (for example, methane and free oxygen) which are produced by living organisms and unstable unless continually replenished by them.
From how may stars, nearby and more remote, might transits of the Earth be observed, and what might alien astronomers learn about Earth? The European Space Agency's Gaia spacecraft, which is assembling a three dimensional map of around a billion stars in the Milky Way, allows estimating this for the first time. The paper, “Past, present and future stars that can see Earth as a transiting exoplanet”, was published in Nature, and is behind a paywall.
Posted at
12:36
CONTINUITY: SpaceX: Mating Starship and Super Heavy
— Elon Musk (@elonmusk) August 7, 2021
Posted at
11:30
CONTEXT: X-Ray Echoes from a Black Hole
The horizontal gaps are an imaging artifact, but the rings themselves are a genuine cosmic feature created by a black hole 9 times as massive as the Sun, located 7,800 light years away. https://t.co/1ALWb1qOSu pic.twitter.com/N6J5dU2YQE
— Corey S. Powell (@coreyspowell) August 7, 2021
Here is the research paper, “A Joint Chandra and Swift View of the 2015 X-Ray Dust Scattering Echo of V404 Cygni”.
Posted at
10:50