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The announcement of the exploding universe theory threw all grades of scientists—from semi-mystic philosophers to earthy materialists—into counterattack. Some critics could not believe that the nebulae move at such breakneck speed. Einstein's Relativity (supreme law of physics) says that nothing can move faster than light (186,000 miles per second). But Hubble and Humason have clocked a nebula about 250 million light-years away that seems to be moving at 26,000 miles per second, more than one-eighth the speed of light. They have glimpsed nebulae twice as far away. If the nebulae continue, on & on into space, they will eventually exceed the relativistic speed limit. Therefore, argue the critics, something is wrong with the speed-distance rule.
Other critics demand more time for the development of the universe. If the universe is expanding, there must have been a time when its billions of nebulae were jostling hotly in one small, close-packed mass. By the exploding universe theory, the date of this cosmological genesis would work out at about 2 billion B.C. Nonsense, say the critics. Certain rocks on the earth's surface, which could hardly have solidified under such hectic circumstances, are thought to be as old as that.
Tired Light. Other critics question the "red shift" as a measure of velocity. The usual explanation of the reddening effect is that the luminous body's motion away from the observer "pulls out" the light waves, making them longer (redder) than normal. But since red light contains less energy per unit (photon) than violet light, Bubble's critics suggest that light may lose some of its energy in traversing space, thus turning redder. It may start out from a distant nebula as young, vigorous violet and arrive at the earth after millions of weary years as old, tired red. If that is what happens, perhaps nebulae are not moving at all?
Hubble is glad to discuss such objections objectively. Even when an adversary uses that subtle, stylized rancor with which the more quarrelsome scientists conduct their controversies, he reacts with courtly tolerance.*
One reason for his balance, and the imagination that helps his work so much, may be that he has never been completely immersed in astronomy, which can easily become an obsession. In summer he goes on long fishing trips, as far away as the Colorado Rockies. He belongs to the American Legion, takes part in "civic activities" like a good Californian. He studies Chinese philosophy. He even knows movie people. Relations between the Mount Wilson astronomers and Hollywood have never been close,* but Hubble has some friends (Aldous Huxley, Michael Arlen, Anita Loos) among the movie colony's intellectual set.
Tested Call. Hubble, 6 ft. 2, strikingly handsome, and built like a heavyweight boxer (just what he was in college), was born in Marshfield, Mo. in 1889, and took his bachelor's degree in 1910 at the University of Chicago. He knew by then that he wanted to be an astronomer, but he took time out for a Rhodes scholarship and two years of law at Oxford.
The wide detour had a purpose. Astronomy, thinks Hubble, is something like the ministry. No one should go into it without a genuine "call." And the only way to test a call, he thinks, is to have another calling to be called away from.