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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 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.

“It’s really exciting. This is such an amazing observation,” says astronomer Andrea Ghez of the University of California, Los Angeles (UCLA), who heads a rival group that is also tracking the star. “This is a direct test [of relativity] that we’ve both been preparing for for years.”

The star, called S2, is unremarkable apart from a highly elliptical orbit that takes it within 20 billion kilometers, or 17 light-hours, of the Milky Way’s central black hole—closer than any other known star. A team led by Reinhard Genzel at the Max Planck Institute for Extraterrestrial Physics (MPE) in Garching, Germany, has been tracking S2 since the 1990s, first with the European Southern Observatory’s (ESO’s) 3.6-meter New Technology Telescope in Chile’s Atacama Desert and later with ESO’s Very Large Telescope (VLT), made up of four 8-meter instruments. Ghez’s team at UCLA also began to observe the star around the same time with the twin 10-meter Keck telescopes in Hawaii.

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Observations made with ESO’s Very Large Telescope have for the first time revealed the effects predicted by Einstein’s general relativity on the motion of a star passing through the extreme gravitational field near the supermassive black hole in the centre of the Milky Way. This long-sought result represents the climax of a 26-year-long observation campaign using ESO’s telescopes in Chile.

Obscured by thick clouds of absorbing dust, the closest supermassive black hole to the Earth lies 26 000 light-years away at the centre of the Milky Way. This gravitational monster, which has a mass four million times that of the Sun, is surrounded by a small group of stars orbiting around it at high speed. This extreme environment — the strongest gravitational field in our galaxy — makes it the perfect place to explore gravitational physics, and particularly to test Einstein’s general theory of relativity.

New infrared observations from the exquisitely sensitive GRAVITY [1], SINFONI and NACO instruments on ESO’s Very Large Telescope (VLT) have now allowed astronomers to follow one of these stars, called S2, as it passed very close to the black hole during May 2018. At the closest point this star was at a distance of less than 20 billion kilometres from the black hole and moving at a speed in excess of 25 million kilometres per hour — almost three percent of the speed of light [2].

Chile’s Very Large Telescope tracks S2 star as it reaches mind-boggling speeds by supermassive black hole.

Hannah Devlin Science correspondent.

Everything you wanted to know about black holes, supernova, and quasars but were afraid to ask.

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Monsignor Georges Lemaître was a Belgian Roman Catholic priest, physicist and astronomer. He is usually credited with the first definitive formulation of the idea of an expanding universe and what was to become known as the Big Bang theory of the origin of the universe, which Lemaître himself called his “hypothesis of the primeval atom” or the “Cosmic Egg”.

Georges Henri Joseph Édouard Lemaître was born on 17 July 1894 at Charleroi, Belgium. After a classical education at a Jesuit secondary school, the Collège du Sacré-Coeur in Charleroi, he began studying civil engineering at the Catholic University of Leuven (Louvain) at the age of 17. In 1914, he interrupted his studies to serve as an artillery officer in the Belgian army for the duration of World War I, at the end of which he received the Military Cross with palms.

An astounding image of the massive black hole at the centre of the Milky Way has been captured by a super telescope in South Africa.

The clearest image yet of the centre of the Milky Way galaxy has been released from South Africa’s shiny new radio telescope, MeerKAT.

This $330 million (R4.4 billion) 64-dish radio telescope will listen to the relatively weak signals from space to help scientists understand what is going on in the far reaches of the universe. It will eventually become part of the Square Kilometre Array (SKA) which will be 50 to 100 times more sensitive than any other radio telescope on earth.

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NASA’s 40-year-old Voyager-1 spacecraft amazes all with ground-breaking new cosmic ray data from interstellar space.

Physicists Pinpoint The Origin Of A Powerful Neutrino For The First Time Ghostly particles called neutrinos can travel nearly unimpeded across the universe. For the first time, physicists have been able to pinpoint the origin of a powerful neutrino.