Word: typed
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Dates: during 1980-1989
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Another report in last week's Nature, while not dealing with 1987A, provided further insight into Type II supernovas. A group led by Chemist Edward Anders and Physicist Roy Lewis, both of the University of Chicago, revealed that they had discovered an abundance of submicroscopic diamonds in a meteorite that fell in Mexico in 1969. While the impact of a meteor slamming into the earth creates enough pressure to crystallize carbon into diamonds, the tiny samples found by the Chicago team apparently resulted from an ancient supernova. The evidence: they contained atomic forms of the gas xenon different from...
...suggested by the name astronomers gave to known neutron stars: pulsars. The spinning neutron stars have intense magnetic fields generating precisely spaced electromagnetic pulses that can be picked up by radio telescopes. Some 440 pulsars have been discovered so far, all of them thought to be remnants of Type II supernovas. The youngest found to date sits right at the center of the Crab nebula, site of the great supernova...
These are the theoretical scenarios. And at first 1987A seemed to be following the rules: it jumped from near invisibility to respectable brightness literally overnight, and while its wave-front speed was high, its spectrum revealed the unmistakable hydrogen-bearing signature of a Type II. But when the International Ultraviolet Explorer satellite reported a rapid drop in ultraviolet light, scientists began to wonder. Says Robert Kirshner, of the Harvard-Smithsonian Center for Astrophysics: "The spectrum we're seeing in the ultraviolet resembles the spectrum of a Type I. That's a puzzle." Admits Texas' Wheeler: "There are some funny features...
...thus the earth -- would die. Nonetheless, he was basically correct: first fire, then ice. The fire will not be an explosion like the one now brightening the Large Magellanic Cloud; the sun is thought to have only about a tenth of the mass necessary to become a Type II supernova and has no stellar companion to contribute the mass necessary to turn it into a Type I blast. But that will be of little comfort to whatever creatures exist on earth when the sun is in its death throes; the $ final solar convulsions, while feeble compared to those...
...tank car on a Norfolk & Western freight broke a coupling and derailed, spilling 19,000 gallons of orthochlorophenol. Sturgeon was evacuated for two days while the spill was cleaned up. Then Monsanto announced that the spilled chemical contained a minute amount of dioxin, the type designated as 2,3,7,8-TCDD and described as the most toxic synthetic chemical known to man. A mere thimbleful was involved. But because the compound has been linked to cancer, fear swept Sturgeon, and the Kemner case took shape...