How Old is the Cosmos?

November 09, 1994

At the turn of the century, physics confronted a dilemma that struck at the heart of its claim to understand natural phenomena. A Scotsman, James Clerk Maxwell, discovered that visible light was a form of electromagnetic radiation traveling at a speed of 186,000 miles per second. Maxwell described the radiation as a wave, but he had no idea how it was propagated. To explain the phenomenon, theorizers posited the existence of a cosmic "ether," which filled all space and served as the medium on which the radiation acted.

Many experiments were devoted to detecting the "ether" and its effect on light rays, but all ended in failure. Finally two American scientists, Albert Michelson and Edward Morley, conclusively demonstrated that the "ether" had no effect on the speed of light, and therefore probably didn't exist. The Michelson-Morley findings inspired an obscure young worker in a Swiss patent office named Albert Einstein to conceive a radically new way of looking at the universe, which he published as the Special Theory of Relativity in 1905.

Today, physicists find themselves at a similar crossroads. Astronomers say new measurements of the distance to the galaxy M100 suggest a revised estimate for the age of the universe that is significantly less than that of the oldest stars. Calculations of the universe's expansion rate indicate the universe may be no more than 8 billion years old, compared with earlier estimates of up to 20 billion years. Since the oldest stars are reliably thought to be about 16 billion years old, the new findings raise the surprising implication that the universe may be younger than some of its components -- a most improbable state of affairs.

This is the kind of conundrum that drives scientists to new conceptions of familiar realities. If the new findings hold up, it will mean either that there is something very wrong with our current model of a universe that has been expanding steadily since the primordial "Big Bang" or that our knowledge of stellar life cycles is seriously flawed. Either way, theorizers will have to re-think some basic issues that previously were considered settled.

It is the nature of the scientific endeavor to find such challenges hugely attractive -- and maddeningly frustrating. We may be on the threshold of a new conception of the universe. The frustrating part is waiting until someone comes along with the genius to explain to us what it all means.

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