Astronomers have discovered the closest, fastest star ever seen orbiting Sagittarius A* (Sgr A*), the 4.3 million-solar-mass black hole at the heart of our galaxy. The faint star, named S301, completes a lap every 8.7 years and skims past the black hole at roughly 55 million mph (90 million km/h) — about 8% the speed of light. Its orbit is so tight that, within about a decade, researchers should be able to measure its spin rate. The discovery was reported Aug. 19 in the journal Nature.
