Word: neutron
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...Theodore Stecher ask archaeologists for help in determining the age of a giant celestial gas cloud. Known as the Gum Nebula, the cloud has been attracting more than usual attention among astronomers. At its center, some 1,500 light-years away from earth, they have discovered a pulsar -a neutron star that emits regularly spaced radio signals. What possible information could archaeologists offer? Quite a bit, the astronomers explain. Both the Gum Nebula and pulsar are remnants of a relatively rare heavenly event: a supernova, the cataclysmic explosion of a massive dying star. The astronomers point out that another supernova...
...ANGELES Correspondent John Wilhelm first seriously considered the possibility of extraterrestrial life four years ago while visiting the mam moth radio telescope at Arecibo, Puerto Rico. Pulsars - radio signals now thought to emanate from rapidly rotating neutron stars in the far reaches of space - had just been discovered. Arecibo Director Frank Drake let Wilhelm listen a audio signals originating light-years away. Recalls Wilhelm: "It was a little like putting a stethoscope to the heart of the universe. Drake did not dismiss the possibility, however slight, that pulsars might in fact be navigation beacons used by an advanced civilization...
...Bell in 1967 recorded blips coming from space at precise intervals, they playfully named the sources LGMs (for Little Green Men) on the chance that they had detected the beacon of an advanced civilization. The LGMs were later named pulsars and recently identified as natural phenomena: the long-sought neutron stars. Despite man's failure to pick up any interstellar communications, however, the entire galaxy could be filled with chatter between advanced civilizations, transmitted by a technique still undiscovered on earth. Says Carl Sagan: "We may be very much like the inhabitants of an isolated valley in New Guinea...
Ordinary reactors "burn" uranium 235, which eventually becomes stable lead. Breeders use either U-235 or man-made plutonium for fuel, but also use as a "fertile" material (a nonfissionable substance that absorbs excess neutrons freed in the chain reaction and becomes fissionable) another form of uranium called U-238. In addition to being more common than U-235, this uranium isotope, when struck by a hurtling neutron, does not break apart as does U-235. Instead, it absorbs the particle and is transmuted, by 20th century alchemy, into fissionable plutonium. Thus the breeder's fertile material is gradually...
...usually affable man, Wiesner has a streak of impatience that makes him walk out of boring meetings. He relaxes aboard a yet unchristened 23-ft. sailboat with a dinghy named Neutron. But he usually puts in two hours of early morning reading at his home in nearby Watertown before cooking breakfast for his family and churning off to the M.I.T. campus for his daily blitz of telephone calls and meetings. His abiding interest in education has led him to campaign successfully for election to the Watertown school board...