Word: nebula
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Dates: during 1970-1979
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...earth matters, but a recent issue contains an appeal that reaches rather far out. In a letter to the magazine, Astronomers John C. Brandt, Stephen P. Maran and 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...
...Nebula supernova occurred much earlier-about 9000 B.C., according to estimates based on the current signal rate of Gum's pulsar. The sudden and brief appearance at that time of what seemed to be a new and brightly glowing star-probably as luminous as a quarter moon and visible even during full daylight-may have sufficiently moved a primitive sky-gazer to scrawl or carve his impressions on a cave wall. And if an archaeologist should ever find such a drawing, its age could be determined by using radioactive "clocks" and other dating methods on other objects...
...multibillion-hertz range into more easily detectable radio frequencies of about 100 million hertz. After adapting this device to the National Radio Astronomy Observatory's 36-ft. dish antenna at Arizona's Kitt Peak, the Bell scientists aimed the radio telescope at the distant Orion Nebula, a region of glowing gases more than 1,600 light-years away, a favorite target of molecule hunters...