Word: ultraviolet
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Dates: during 1960-1969
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NASA's assumption was based on OAO-II's report of unexpectedly powerful ultraviolet radiation from half a dozen nearby galaxies. If this is true, NASA scientists reasoned, distant galaxies probably give off large amounts of the same invisible radiation. But those galaxies are receding from the earth (because of the expansion of the universe) at speeds that would cause ultraviolet light to shift toward the red end of the spectrum into visible frequencies. So the NASA men assumed the visible light from distant galaxies is intrinsically brighter than previously believed; therefore those galaxies must be farther away...
...first place, NASA's critics pointed out, ultraviolet radiation accounts for no more than a tenth of thz radiation from a galaxy. Thus, even a large increase in this component would not greatly affect a galaxy's overall brightness. Besides, modern astronomers always compensate for the "red shift" of light when viewing distant galaxies and quasars...
...cosmological calculations in no way detracts from the splendid performance of the Orbiting Astronomical Observatory. Operating in a 480-mile-high orbit above the polluted obscuring atmosphere and equipped with 11 telescopes, it has given astronomers a view of the skies unattainable on earth. In addition to its ultraviolet readings-which will almost surely contribute to knowledge about galactic structure-OAO II has discovered that young, "hot" stars are losing far more of their matter in the process of maturation than had hitherto been thought: as much as the mass of the earth in a single year. Data from...
...also observed that "blue giants-massive, hot stars-are fainter in the ultraviolet than the rest of the main sequence stars" (Main sequence stars are middle-aged stars such as the sun). This second result can be explained by the structure of the blue giants. Davis said, but the reason for the brightness...
...telescope cameras have sent back nearly 5000 ultraviolet pictures, primarily photographing the stars lying in the plane of the Milky Way. A satellite was necessary to obtain these pictures because the earth's atmosphere blocks most types of ultra-violet light and makes ground observations in ultra-violet wave-lengths impossible...