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No. 413:
Edwin Hubble

Today, Edwin Hubble holds a new Universe up to our view. The University of Houston's College of Engineering presents this series about the machines that make our civilization run, and the people whose ingenuity created them.

Now we've set the Hubble Observatory in space, and we wait to see all that it has to show us. But who was Hubble? Where does this great space telescope get its name?

Edwin Hubble was born in Missouri in 1889. He was educated at the University of Chicago and Oxford. After WW-I he joined the Mount Wilson Observatory. And there, until his death in 1953, he expanded the Universe far beyond what it had been.

When he began, the Universe consisted of only one galaxy -- our Milky Way. By the time Hubble died, our home had expanded into a whole starry host of galaxies.

Spiral nebulae were well known when Hubble was young. Some even thought they might be other galaxies -- other island universes. But how could we tell? The nebulae wouldn't make sense until we knew their real size and their real distance from us.

Hubble made the first crack in the mystery in 1923. In Andromeda, he discovered a kind of pulsating star called a Cepheid. He also used spectroscopy to relate its pulsations to its distance from Earth. A year later, he had enough data to write a friend about the huge distances he'd calculated. The fellow wrote back to him, "Here is the letter that has destroyed my Universe." And so it had! But there was more.

Hubble unloaded a second bombshell in 1929. Not only do we live in a vast place, but it's growing ever more vast. He found that other galaxies move away from ours, 90 miles per second faster for each light year of distance from Earth.

What could that mean? Why should the speed of retreat increase with the distance from Earth? The answer finally came from relativity theory. Space itself stretches in the vastness of the Universe. In those days, relativity stretched belief as well. Hubble was the finest of experimentalists. Yet, he chose to support the relativity idea for the most theoretical reason. He backed it because it was elegantly simple.

Now we've set a telescope in orbit to gaze at our back yard -- 15 billion light years in its reach and expanding by twelve trillion miles each year. Long ago John Quincy Adams set out to build more observatories. He coined the term "Lighthouses in the Sky." It earned him ridicule at the time, but I like it. It fits this new lighthouse orbiting our night skies. And Hubble's name is right for it. For he first told what immensities it will steer us to.

I'm John Lienhard, at the University of Houston, where we're interested in the way inventive minds work.

(Theme music)

Hetherington, N.S., Hubble's Cosmology. American Scientist, Vol. 38, March-April, 1990, pp. 142-151.