This artist’s impression shows the orbits of stars around supermassive black hole at the centre of the Milky Way. In 2018 one of these stars, S2, will pass very close to the black hole and present the best opportunity to study the effects of very strong gravity and test the predictions of Einstein’s general relativity in the near future.

The GRAVITY instrument on the ESO Very Large Telescope Interferometer is the most powerful tool for measuring the positions of the S2 star in existence and it was successfully tested on the S2 star in summer 2016. The orbit of S2 is highlighted in red and the position of the central black hole is marked with a red cross.

Credit: ESO/L. Calçada