Image of the Galactic Centre

The central parts of our Galaxy, the Milky Way, as observed in the near-infrared with the NACO instrument on ESO's Very Large Telescope. The position of the centre, which harbours the (invisible) black hole known as Sgr A*,with a mass 4 million times that of the Sun, is marked by the orange cross.

The star S2 will make a close pass around the black hole in 2018 when it will be used as a unique probe of the strong gravity and act as a test of Einstein's general theory of relativity.