Star racing around black hole at center of our galaxy

UCLA astronomers report the discovery of a remarkable star that orbits the enormous black hole at the center of our Milky Way galaxy in a blistering 11-and-a-half years — the shortest known orbit of any star near this black hole. The star, known as S0-102, may help astronomers discover whether Albert Einstein was right in his fundamental prediction of how black holes warp space and time, said research co-author Andrea Ghez, leader of the discovery team and a UCLA professor of physics and astronomy who holds the Lauren B. Leichtman and Arthur E. Levine Chair in Astrophysics. Before this discovery, astronomers knew of only one star with a very short orbit near the black hole: S0-2, which Ghez used to call her "favorite star" and whose orbit is 16 years. (The "S" is for Sagittarius, the constellation containing the galactic center and the black hole). "I'm extremely pleased to find two stars that orbit our galaxy's supermassive black hole in much less than a human lifetime," said Ghez, who studies 3,000 stars that orbit the black hole, and has been studying S0-2 since 1995. Most of the stars have orbits of 60 years or longer, she said. "It is the tango of S0-102 and S0-2 that will reveal the true geometry of space and time near a black hole for the first time," Ghez said.