September 20, 2020

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Draging Spacetime with White Dwarf’s Spin

Draging Spacetime with White Dwarf’s Spin

Over a century ago, Albert Einstein predicted that massive rotating bodies slightly drag spacetime around them, just like a rotating bowling ball on a rug creates a tiny warp in the fabric. Now, for the first time ever, astronomers have detected and measured this frame-dragging effect in the strong gravitational field of a pair of distant stars. The result, published January 30th in Science, sheds more light on the binary’s evolution.

In 1918 Austrian physicists Josef Lense and Hans Thirring showed that frame-dragging by the Sun should produce a tiny extra precession, a spirograph-like progression of the planets’ orbits, known as Lense-Thirring precession.

They also concluded that this Lense-Thirring precession (not to be confused with the much larger perihelion precession of Mercury) is way too small to measure. That has changed over the past decade, as even-smaller frame-dragging by the rotating Earth has been detected in high-precision satellite experiments, such as NASA’s Gravity Probe B and the LAGEOS laser-ranging satellites.

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