Star’s black hole encounter puts Einstein’s theory of gravity to the test
http://www.sciencemag.org/news/2018/07/star-s-black-hole-encounter-puts-einstein-s-theory-gravity-test
An artist’s impression of the star S2 passing close to the supermassive black hole at the center of the Milky Way.
For more than 20 years, a team of astronomers has tracked a single star whipping around the supermassive black hole at the center of our galaxy at up to 25 million kilometers per hour, or 3% of the speed of light. Now, the team says that the close encounter has put Albert Einstein’s theory of gravity to its most rigorous test yet for massive objects, with the light from the star stretched in a way not prescribed by Newtonian gravity. In a study announced today, the team says it has detected a distinctive indicator of Einstein’s general theory of relativity called “gravitational redshift,” in which the star’s light loses energy because of the black hole’s intense gravity.