First image of a black-hole shadow
First image of a black-hole shadow
Overview
In April 2019 the Event Horizon Telescope collaboration released the first image of a black hole's shadow: the glowing ring around the 6.5-billion-solar-mass object at the centre of galaxy M87. Synchronising millimetre-wave dishes across four continents into an Earth-sized interferometer, the team resolved structure on the scale of the event horizon for the first time. The ring's size and asymmetry matched general relativity's predictions, making the shadow image a direct test of gravity in its strongest regime.