Artist’s animation of S2’s precession effect

Observations made with ESO’s Very Large Telescope (VLT) have revealed for the first time that a star, S2, orbiting the supermassive black hole at the centre of the Milky Way moves just as predicted by Einstein’s theory of general relativity. Most stars and planets have a non-circular orbit and therefore move closer and further away from the object they are rotating around. S2’s orbit precesses, meaning that the location of its closest point to the supermassive black hole changes with each turn, such that the next orbit is rotated with regard to the previous one, creating a rosette shape. This effect, known as Schwarzschild precession, had never before been measured for a star around a supermassive black hole.

This animation shows S2’s orbit around Sagitarius A*, the supermassive black hole at the centre of the Milky Way. The precession movement is exaggerated for easier viewing.