There’s a direct image

So far we’ve had plenty of compelling indirect evidence for black holes: bursts of radiation, gravitational waves or dynamical effects on other bodies that couldn’t have been produced by any other object known to science. But the final clincher came in April 2019 in the form of a direct image of the supermassive black hole at the centre of active galaxy Messier 87. This stunning photo was taken by the Event Horizon Telescope, which consists of a large network of telescopes scattered all over the world rather than a single instrument. The more telescopes that can participate, and the more widely spaced they are, the better the final image quality. The result clearly shows the dark shadow of the 6.5-billion-solar-mass black hole against the orange glow of its surrounding accretion disc.