Free Astronomy Magazine November-December 2026

45 NOVEMBER-DECEMBER 2026 ASTRO PUBLISHING T his illustration shows how a spinning black hole drags space-time around it, a phenom- enon known as Lense-Thirring effect. If a star gets close enough to a spinning black hole, its orbit will change in a way that can be measured over long timescales with sufficiently pre- cise telescopes and instruments. [ESO/M. Kornmesser] fact that stars cannot form so close to a massive black hole, indicate that the star was likely part of a bi- nary pair that was torn apart by the tidal forces of Sagittarius A*. In the process, S301 became trapped by the black hole’s gravity while its companion star was kicked out with high velocity, most likely enough to leave the galaxy alto- gether. Follow-up observations with GRAVITY+, and with the MICADO instrument on ESO’s upcoming Extremely Large Telescope (ELT), will be crucial for tracing S301’s path over the next decade, as it makes its next closest passage in 2031. Observing at least two com- plete orbits of S301 allows its trajectory to be con- strained with high enough precision to enable the team to directly determine the spin of Sagittarius A* for the first time. “That would be a dream come true,” says Mang. https://www.youtube.com/watch?v=xF3017r3dV4 A stronomers have discovered the fastest known star in our galaxy, the Milky Way, or- biting the black hole at its centre. The star, named S301, was detected with ESO’s Very Large Telescope Interferometer (VLTI) and it reaches speeds of more than 8% the speed of light. It comes closer to the black hole than any other star observed before, so close that it feels the effects of the black hole’s rotation. This video summarises the discovery. [ESO] since to constrain its orbit. They could also trace S301’s orbital his- tory back to 2017, finding that it last made its closest approach to the central black hole in early 2023. S301’s orbital properties, and the metre telescopes that can act together as an interferometer,” says co-author Frank Eisenhauer, GRAVITY+ Principal In- vestigator and Director at MPE. With GRAVITY, and later with GRAVITY+, the team managed to catch a first glimpse of the new star in spring 2023 and have followed it !