100,000 times faster than a passenger plane: the fastest star in the Milky Way

Astronomers have discovered S301, the fastest star in the Milky Way, orbiting the black hole at the center of the galaxy at a speed of about 25,000 kilometers per second. The star completes an orbit around the black hole in just 8.7 years, and at its closest point it reaches a distance of 12 times the distance between Earth and the Sun. Researchers hope to use it to test Einstein's theory of relativity and measure the black hole's spin.

Astronomers have discovered S301, the fastest star in the Milky Way, orbiting the supermassive black hole Sagittarius A* at the center of the galaxy. The star moves at a speed of about 25,000 kilometers per second, 100,000 times faster than a passenger plane. It completes a full orbit around the black hole in just 8.7 years – a very short time in astronomical terms. At the closest point in its orbit, it reaches a distance roughly 12 times the distance between Earth and the Sun. According to Reinhard Genzel, director at the Max Planck Institute for Extraterrestrial Physics and winner of the 2020 Nobel Prize in Physics, many years of precise tracking of stars orbiting Sagittarius A* enabled the discovery. He said that the extreme proximity of S301 to the black hole opens a new window for studying the fundamental properties of space and time in a region where gravity is immense. Researchers hope that with the help of this star, they will be able to test Einstein's theory of relativity and measure the black hole's spin.