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Ultimate Truths. The astonishing distances and speeds proved particularly provocative to cosmologists, who deal with such heady subjects as the history and nature of the universe. More than any other scientists, they are keenly aware that when they look into the night skies they are looking into the past. Because light travels at a swift but finite speed, the sun is seen as it was eight minutes ago, the nearest star as it was four years ago, and the near est galaxy as it appeared 2,000,000 years ago. If Maarten Schmidt and his colleagues were correct, they were seeing quasars as they looked billions of years ago. This long-range view seemed to provide a prime tool for testing cosmological theories about the origins of the universe.
¶ STEADY-STATE theorists, led by British Astronomer Fred Hoyle, claim that the universe has always existed, has always been expanding and has looked the same at any point in time. As the galaxies move farther away from each other, steady-staters believe, new galaxies are constantly being formed out of hydrogen that is created and fill the gaps, keeping the expanding universe at a constant density.
¶ BIG-BANG believers, including Cambridge University Radio Astronomer Martin Ryle, think that the universe began about 10 billion years ago in an incredibly huge explosion of densely packed matter. Some big-bangers feel that the fragments of that explosion—now galaxies—will continue to move outward and away from each other forever, like spots on the surface of an expanding balloon. Others suggest that the gravitational attraction between the galaxies will eventually overcome their outward motion, pulling them all back together in a cataclysmic collision that will end the universe.
¶ OSCILLATING-universe proponents, such as Astronomer Allan Sandage of Mount Wilson and Palomar Observatories, lean toward the concept of a universe that expands after a big bang, contracts to an extremely dense state, and then explodes outward again in an 80-billion-year, never-ending cycle. In one sense that universe, like the steady-state universe, is infinite. Instead of being completely destroyed, it expands again after each contraction. It has been about 10 billion years since the last big bang, Sandage speculates, and only 70 billion years remain before the galaxies crush together again to start the next cycle.
Of the three theories, the steady state seems to have been dealt the most severe blow by studies of the 30 quasars whose red shifts have been determined so far. Because the number of quasars at greater distances—and thus further back in time—appears to be larger, quasars seem to have been more numerous when the universe was younger. And they seem to have disappeared as the universe evolved—a direct contradiction of the major feature of the steady-state universe. In addition, quasars, as calculated by their red shifts, are gradually slowing down, a phenomenon that can be explained by the mathematics of the big-bang and oscillating universes—but not by the equations of the steady state.