STEADY-STATE UNIVERSE

Steady-State Universe
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Fred Hoyle

Quasars

Arno Penzias and Robert Wilson

Cosmic Background Radiation
 

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The Big Bang
 

Proposed in 1948 by Hermann Bondi, Thomas Gold, and Fred Hoyle, the steady-state theory was based on an extension of something called the perfect cosmological principle. This holds that the universe looks essentially the same from every spot in it and at every time. (This applies only to the universe at large scales; obviously planets, stars, and galaxies are different from the space between them.)

       Obviously, for the universe to look the same at all times, there could have been no beginning or no end. This struck a philosophical chord with a number of scientists, and the steady-state theory gained many adherents in the 1950s and 1960s. How could the universe continue to look the same when observations show it to be expanding, which would tend to thin out its contents? Supporters of this cosmology balanced the ever-decreasing density that results from the expansion by hypothesizing that matter was continuously created out of nothing. The amount required was undetectably small—about a few atoms for every cubic mile each year.

       The steady-state theory began to wither in the 1960s. First, astronomers discovered quasars, the highly luminous cores of very distant galaxies. Because the vast majority of quasars lie exceedingly far away, their existence proves that the perfect cosmological principle cannot be true—the distant and therefore ancient universe is not the same as the younger universe nearby. The death knell for the theory sounded when radio astronomers Arno Penzias and Robert Wilson discovered the cosmic microwave background, the leftover radiation from the Big Bang. The steady-staters had no reasonable way to explain this radiation, and their theory slowly faded away as so many of its predecessors had.

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