Word: quasars
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Dates: during 1970-1979
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...astronomers, this was too much of a coincidence. Writing in Nature last May, they suggested that what they might be seeing was two images of the same quasar. How was this possible? More than half a century ago, scientists realized a bizarre consequence of Einstein's general relativity theory: if a very massive object were located almost directly between the earth and a distant star, its tremendous gravity would act as a "gravitational lens" that could bend the starlight into two different paths. To produce the effect observed at Kitt Peak, the astronomers calculated, a huge galaxy...
...that poses a dilemma for physicists. If quasars are really so far away, yet bright enough to be detected through ordinary optical and radio telescopes, they must be radiating more energy than 50 to 100 galaxies, each of which contains hundreds of billions of stars. Yet careful measurements by radio telescopes indicate that a quasar is much smaller than a galaxy and perhaps no bigger than a solar system. The problem: no physical process yet known to scientists can generate such incredible energy in so tiny a volume...
This quandary has led some astronomers to suggest that the quasars' red shifts are caused by something other than their great distance. Perhaps the light is simply "tired" after its long journey and is arriving at a lower frequency. Or it might be "stretched" toward the red by the strong gravitational field of the quasar. Another possibility: maybe quasars have been exploded out of nearby galaxies at great velocities. Any of these explanations could leave the quasars near enough to the earth to account for their observed brightness, and at the same time give them their enormous red shifts...
...Astronomer Joseph S. Miller, using the Lick Observatory's powerful 120-in. (3-meter) telescope near San Jose, Calif., has produced powerful new evidence to support the "distant" quasar argument. Expanding on earlier work at the Hale Observatories by Beverley Oke and James Gunn with the 200-in. (5-meter) Palomar telescope, he and two colleagues studied one of the so-called BL Lacertae objects, which until the late 1960s were thought to be ordinary variable stars, but now are known to resemble quasars...
...object picked by Miller was a quasar-like structure surrounded by an old, spherical galaxy. When the Miller group measured the red shift of light from that galaxy, the astronomers determined that the island of stars was 1 billion light-years away. And because the quasar-like object was imbedded in the galaxy, it was presumably the same great distance from the earth. Furthermore, the galaxy's brightness was consistent with that distance. Miller's conclusion: if the red shift was indeed a correct yardstick for an object that so closely resembled a quasar, it probably was accurate...