100 Years of General Relativity: Why Einstein Still Stands

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100 Years of General Relativity: Why Einstein Still Stands - by Devin Powell/ Science/ Popular Science/ popsci.com

"One hundred years ago this month, Albert Einstein redefined what gravity is, overthrowing his own hero Isaac Newton.

Newton had imagined gravity to be a force like any other that pulls on things to get them going. But Einstein wove gravity into very fabric of space and time, molding an invisible landscape of hills and valleys through which objects move. The equations describing this vision, known as the general theory of relativity, have since become a cornerstone of modern physics—opening new doors for understanding everything from how planets and stars move to existence of dark matter and the early days of the universe itself.

“Today it really is the standard model for gravity,” says Clifford Will, a physicist at the University of Florida who has devoted his career to the theory. “It has passed every experimental test with flying colors.”..."

Negative of a solar eclipse verifying Einstein's general relativity

In this 1919 negative of a solar eclipse, British scientist Sir Arthur Eddington helped verify Einstein's theory of general relativity, showing light bending around the Sun as predicted in the theory.

Wikimedia Commons/Public Domain


Richard

 

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A Century Ago, Einstein's Theory of Relativity Changed Everything - by Dennis Overbye/ Science/ International New York Times/ The New York Times/ nytimes.com

"PRINCETON, N.J. — By the fall of 1915, Albert Einstein was a bit grumpy.
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And why not? Cheered on, to his disgust, by most of his Berlin colleagues, Germany had started a ruinous world war. He had split up with his wife, and she had decamped to Switzerland with his sons.

He was living alone. A friend, Janos Plesch, once said, “He sleeps until he is awakened; he stays awake until he is told to go to bed; he will go hungry until he is given something to eat; and then he eats until he is stopped.”

Worse, he had discovered a fatal flaw in his new theory of gravity, propounded with great fanfare only a couple of years before. And now he no longer had the field to himself. The German mathematician David Hilbert was breathing down his neck.

So Einstein went back to the blackboard. And on Nov. 25, 1915, he set down the equation that rules the universe. As compact and mysterious as a Viking rune, it describes space-time as a kind of sagging mattress where matter and energy, like a heavy sleeper, distort the geometry of the cosmos to produce the effect we call gravity, obliging light beams as well as marbles and falling apples to follow curved paths through space.

This is the general theory of relativity. It’s a standard trope in science writing to say that some theory or experiment transformed our understanding of space and time. General relativity really did..."

Chad Hagen


Richard