Frame-dragging measurement around the Earth sets new precision record
Laser-ranging technique proves Einstein right again The post Frame-dragging measurement around the Earth sets new precision record appeared first on Physics World .
Physicists have used laser ranging to measure the frame dragging of Earth with remarkable precision, achieving an uncertainty of just one part in a thousand. This high-precision measurement confirms Einstein's theory of general relativity even further and also sets more stringent constraints on alternative theories explaining the universe's accelerated expansion.
Frame dragging, a prediction of general relativity, occurs when a massive, rotating object not only curves spacetime but also drags it around as it rotates. The effect is much more noticeable around large objects like black holes but can still be detected around Earth. However, measuring this tiny shift in orbital plane is challenging due to Earth's non-spherical shape.
To overcome this, researchers utilized data from Laser Relativity Satellite 2 (LARES-2) and its predecessor LAGEOS. These satellites act like a massive gyroscope, and their position can be precisely measured using laser ranging. LARES-2's spherical shape and substantial weight allowed researchers to isolate the influence of Earth's gravity, removing the effects of Earth's lunisolar tides.
This precise measurement will help strengthen tests of alternative theories to general relativity, particularly those related to the accelerated expansion of the universe and phenomena like the flow of time around rotating black holes.
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