December 30, 1924, Edwin Hubble announced the results of his observations of distant objects in space.
In 1924, he announced the discovery of a Cepheid, or variable star, in the Andromeda Nebulae. Since the work of Henrietta Leavitt had made it possible to calculate the distance to Cepheids, he calculated that this Cepheid was much further away than anyone had thought and that therefore the nebulae was not a gaseous cloud inside our galaxy, like so many nebulae, but in fact, a galaxy of stars just like the Milky Way. Only much further away. Until now, people believed that the only thing existing outside the Milky Way were the Magellanic Clouds. The Universe was much bigger than had been previously presumed.
Later Hubble noted that the universe demonstrates a “red-shift phenomenon.” The universe is expanding. This led to the idea of an initial expansion event, and the theory eventually known as Big Bang.
Hubble’s life offered several surprises, and firsts:
Hubble was a tall, elegant, athletic, man who at age 30 had an undergraduate degree in astronomy and mathematics, a legal degree as a Rhodes scholar, followed by a PhD in astronomy. He was an attorney in Kentucky (joined its bar in 1913), and had served in WWI, rising to the rank of major. He was bored with law and decided to go back to his studies in astronomy.
In 1919 he began to work at Mt. Wilson Observatory in California, where he would work for the rest of his life. . . .
Hubble wanted to classify the galaxies according to their content, distance, shape, and brightness patterns, and in his observations he made another momentous discovery: By observing redshifts in the light wavelengths emitted by the galaxies, he saw that galaxies were moving away from each other at a rate constant to the distance between them (Hubble’s Law). The further away they were, the faster they receded. This led to the calculation of the point where the expansion began, and confirmation of the big bang theory. Hubble calculated it to be about 2 billion years ago, but more recent estimates have revised that to 20 billion years ago.
An active anti-fascist, Hubble wanted to joined the armed forces again during World War II, but was convinced he could contribute more as a scientist on the homefront. When the 200-inch telescope was completed on Mt. Palomar, Hubble was given the honor of first use. He died in 1953.
“Equipped with his five senses, man explores the universe around him and calls the adventure Science.”
That news on December 30, 1924, didn’t make the first page of the New York Times. The Times carried a small note on February 25, 1925, that Hubble won a $1,000 prize from the American Academy for the Advancement of Science.
Update, December 31: CBS’s Sunday Morning has an “Almanac” feature weekly; Hubble was featured on December 30. Unfortunately CBS has not posted the video. However, I did find a description of Hubble’s work on YouTube — in true, irritating internet fashion, stripped of citations. The video is below. If you know details — who made the video, where good copies might be available — please note it in comments.
Update: See the 2009, improved Hubble Day post here.