A century later, Einstein’s gravity theory to be tested

Nearly a century after Albert Einstein developed a radical new view on gravity, physicists are preparing a satellite-borne experiment, to be...

Nearly a century after Albert Einstein developed a radical new view on gravity, physicists are preparing a satellite-borne experiment, to be launched on Monday, meant to verify two important predictions of that theory. Einstein’s General Theory of Relativity was published in 1916 and went well beyond the classic physics of Isaac Newton in describing the gravitational forces at play between bodies large and small.

In Einstein’s theory, gravity is not the result of some mysterious attraction between two objects but rather is a consequence of the fundamental structure of the cosmos. A smaller mass is drawn toward a larger one because the larger one creates a bigger warp in the fabric of spacetime, the three dimensions of space and the fourth dimension of time treated as a single construct.

That fabric can be represented as a taut rubber sheet. Put a large object, such as the sun, on it and sheet will sag deeply. Less massive objects, such as Earth, will tend to roll toward the larger mass. As early as 1919, astronomers verified a key prediction of Einstein’s theory by recording the bending of light from a distant star as it passed close to the massive presence of the sun.

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Another experiment in 1976, called Gravity Probe A, verified that the flow of time is slowed near a large body. A rocket carried an atomic clock to an altitude of about 6,200 miles. As the Earth’s pull weakened, the instrument showed that time speeded up almost imperceptibly — by about 1 part in 10 billion compared to the rate on Earth. The new experiment, to be launched aboard a Delta II rocket from Vandenberg Air Force Base, is called Gravity Probe B.

The experiment will verify not only the warping of space by the Earth’s mass but also whether and how the rotating Earth drags space and time with it, twisting it a bit like cotton candy spun around a stick. The phenomenon is called frame dragging. —(LAT-WP)

Day after PM Modi’s visit to the town, Manipur’s Churachandpur sees violent protest

India18 min ago

Protests in Manipur's Churachandpur turned violent as two men were arrested for damaging decorations for PM Modi's visit. The crowd demanded their release and attempted to storm the police station. The men were eventually released after a bail hearing. The incident occurred after a clash between locals and police on Thursday, but the situation had calmed down before Saturday's visit.

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