The 2017 observations from the Event Horizon Telescope (EHT) of M87*, a 6.5-billion-solar-mass black hole in the center of the giant elliptical galaxy Messier 87, have led to the first measurement of the size of a black-hole shadow. Based on an analysis of M87*’s shadow, the EHT researchers have now conducted a unique test of general relativity, deepening understanding about the unusual properties of black holes and ruling out many alternatives. Visualization...
