Word: 3c
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Dates: during 1960-1969
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...light-year is the distance that light, at a speed of 186,000 miles per second, travels in a year: about 6 trillion miles. * "3C" stands for the Third Cambridge Catalogue of Radio Sources. The other numbers designated each source's position...
Strange Lines. In 1962, a group of radio astronomers led by Cyril Hazard tried a subtle tactic in an effort to pinpoint a strong radio source that searchers with optical telescopes could not identify. Pointing the Parkes, Australia, 210-ft. dish antenna toward the source, known only as 3C 273,* Hazard's group recorded the precise time that its signals were eclipsed, or blotted out, by the sharp leading edge of the passing moon and the time when they reappeared from behind its trailing rim. Because the position of the moon can be accurately calculated for any given time...
When the Australian data reached Astronomer Maarten Schmidt late in 1962, he was able to locate 3C 273 in earlier photographs, which revealed it to be a round, fuzzy, starlike object with a faint, glowing jet protruding from it; he had discovered a quasar that was brighter than any yet recorded by his colleagues...
...3C 273 was racing away from earth, Schmidt realized, the wave length of its light would be lengthened - just as the wave length of sound from a train's whistle lengthens (thereby dropping in pitch) as it speeds away from a listener at the railroad station. Such an effect on light is known to astronomers as a "red shift" because it moves the characteristic lines of spectral light toward the red, longer wave length end of the spectrum...
State of Shock. Acting on his hunch, Schmidt assumed that the lines he saw were really hydrogen lines. He measured the shift and calculated that 3C 273 was moving away at 15% of the speed of light, or about 28,000 miles per second. This meant, according to Hubble's law, that the quasar must be about 1.5 billion light-years from the earth, instead of being a faint, nearby star - as most astronomers had assumed...