18 JAN 2013 by ideonexus
The Story of How the Universe's Size was Determined
It was into this fiery climate of the 1920s that the Protestant-raised Hubble, adorned with the cape, cane, and British accent he had adopted while at Oxford, returned after the war. He arrived at the Carnegie Institution of Washington-funded Mount Wilson Observatory outside Pasadena, California, insisting on being called "Major Hubble."^'' Looking through the great Hooker telescope—at one hundred and one inches in diameter and weighing more than one hundred tons it was by far the largest a...
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Includes a cautionary tale of Shapely, who helped prove the Sun was not the center of the Universe, but who thought the Milky Way was all the Universe there was without empirical data.
18 JAN 2013 by ideonexus
Einstein's Cosmological Constant
Georges Lemaitre was a pudgy, pinkish Belgian Jesuit abbe—a Catholic priest—who also happened to be a skilled astronomer. Lemaitre had noticed that Einstein's general theory of relativity would have implied that the universe was expanding but for a troublesome little mathematical term called the cosmological constant that Einstein had inserted into his equations. Lemaitre saw no convincing reason why the cosmological constant should be there. In fact, Einstein himself had originally calc...
1 He put the constant into his theory to keep the Universe static, but observations demonstrated it was expanding, so he changed his theory to match the evidence.
