Milky Way's fastest star rockets around Sagittarius A* at 8% light speed

Astronomers have identified S301, the Milky Way’s fastest star, racing around the galaxy’s supermassive black hole Sagittarius A* at about 15,500 miles per second (over 8% of light). Its tight 8.7-year orbit, roughly 12 AU from the black hole, offers a novel way to probe Sagittarius A*’s spin and test general relativity via frame dragging, using the GRAVITY instrument on ESO’s Very Large Telescope Interferometer. The discovery, reported in Nature, could allow direct measurements of the black hole’s spin within a decade as researchers continue to monitor two full orbits; S301 may have been captured from a binary system.