Milky Way’s fastest star orbits our supermassive black hole so closely it feels its spin

Astronomers using ESO's Very Large Telescope Interferometer have discovered S301, the fastest known star in the Milky Way, orbiting the supermassive black hole Sagittarius A* at 25,000 km/s — over 8% of the speed of light — and completing an orbit in just 8.7 years. Published in Nature by the GRAVITY+ collaboration, the star passes close enough to feel the black hole dragging spacetime, making it the first star that could directly measure a supermassive black hole's spin — a key test of Einstein's general relativity.