Published : 28 Aug 2026, 11:34 PM
Updated : 08 Sep 2026, 09:36 AM
A star racing around the supermassive black hole at the centre of the Milky Way has broken two records at once -- it is both the fastest star ever observed and the closest to a black hole ever found.
Named S301, the star reaches a peak speed of more than 8 percent of the speed of light at its nearest point to Sagittarius A* (Sgr A*), the black hole at the heart of our galaxy.
At its closest, S301 passes within roughly 1.8 billion kilometres of Sgr A* -- about 12 times the distance between Earth and the sun, reports New Scientist.
That puts it 10 times closer to the black hole than the previous record-holder.
Stefan Gillessen at the Max Planck Institute for Extraterrestrial Physics in Germany and his colleagues discovered S301 using the Very Large Telescope in Chile. They have been tracking it since 2023.
"If you were living on a planet around this star, the size of the black hole at closest approach would appear similar to the full moon from Earth -- it would be absolutely stunning," Gillessen said.
At such close range, S301 passes through one of the most extreme gravitational environments in the universe -- and that makes it scientifically invaluable.
Near a black hole, space and time bend and stretch.
If the black hole is also spinning, it drags space-time around with it in a phenomenon known as frame-dragging. S301 is the first star ever found close enough to feel that effect.
Measuring how S301 moves could allow scientists to finally determine whether -- and how fast -- Sgr A* is spinning.
That would be a major breakthrough: a black hole's spin is one of only three properties it can ever have, alongside mass and electric charge.
"We drop a leaf in the wind and see how the air is moving by measuring that leaf," Gillessen said.
"A star is just the perfect leaf to drop to see the movement of space-time."
Pinning down the spin of Sgr A* using S301 alone could take around a decade, Gillessen said.
But finding more stars in similar orbits would speed that up considerably.
"With one star, it would take a while, but it would still be the best constraint on spin that we've ever had by far," said Ziri Younsi at University College London.
The mass of Sgr A* was worth a Nobel Prize in Physics in 2020. Gillessen suggested its spin could one day earn the same honour.
"If you find the spin, you might expect a call from Stockholm in 20 years," he said.
