The Day We Found the Universe - Marcia Bartusiak [76]
Here's where the relativistic geometry makes a difference: Because Mercury is situated so close to the Sun, whose mass has created a sizable space-time crater, it has more of a “dip” to contend with, more so than the other planets. Einstein declared that the added shift in Mercury's orbit was caused solely by Mercury's proximity to the Sun, not by some yet-to-be-observed inner planet. This wasn't just a vague prediction; the equations of general relativity accounted for Mercury's extra 43 arcseconds of shift per century with utmost precision.
Arthur Eddington, for one, was immediately smitten by Einstein's groundbreaking opus. “Whether the theory ultimately proves to be correct or not, it claims attention as being one of the most beautiful examples of the power of general mathematical reasoning,” he wrote in his account of general relativity, the first book on the subject to appear in English. With Eddington acting as Einstein's translator and champion, the two were often linked in people's minds. An accomplished popularizer of science, Eddington said that Einstein had taken “Newton's plant, which had outgrown its pot, and transplanted it to a more open field.” Eddington was becoming so proficient at explaining relativity that “people seem to forget that I am an astronomer and that relativity is only a side issue,” he lamented after one wearying interview with reporters.
Arthur Eddington (AIP Emilio Segrè Visual Archives)
For Eddington to serve as a spokesman for a radical new theory was somewhat out of character for him. He was usually reserved to the point of shyness, so shy, said physicist Hermann Bondi, that “he couldn't talk at all… When anybody was with him … he played with his pipe, and emptied it and re-stuffed it, and occasionally said a word about the weather.” A thin man of average height but with penetrating eyes, he lived with his sister, who served as homemaker and hostess at their Cambridge Observatory residence. A devout Quaker and pacifist, Eddington remained at Cambridge University in Great Britain during World War I, having been declared valuable to the “national interest” at his university post.
As both an astronomer and a theorist, Eddington divined early on the revolutionary significance of Einstein's ideas: that the general theory of relativity was offering a means to comprehend the workings of the cosmos within a rational and mathematical framework. While Newton's laws were fine for predicting the behavior of comets, planets, and stars, only general relativity could deal with the immensity of space-time as a whole. And at the moment Eddington was beginning to work on a translation of general relativity for his colleagues, Einstein was already at work applying his revolutionary new theory to the universe at large.
For Newton, space was eternally at rest, merely an inert and empty container, a three-dimensional stage through which objects moved about. But general relativity changed all that. Now the stage itself became an active player, since the matter within the cosmos sculpts its overall curvature. With this new insight into gravity, physicists could at last make predictions about the universe's behavior, an innovation that moved cosmology out of the realm of philosophy, its long-standing home, and transformed it into a working science.
Einstein was the first to do this. In 1917, just as Shapley in California was revamping the Milky Way, he published a paper in Germany titled “Cosmological Considerations Arising from the General Theory of Relativity.” In it he explored how his new