After five years of effort, the first image of Sagittarius A*, 26,000 light-years away at the centre of the Milky Way, produced by the Event Horizon Telescope, has proved it to be a supermassive black hole. A CUHK scholar and a student from the Department of Physics are Hong Kong’s only participants in the team and have studied the simulation of gas movement and the mechanism of infalling gas around the black hole using supercomputers to help unravel the mystery of black holes.