In the center of the galaxy M87, stars seem to orbit an invisible object. By observing the path of the stars, scientists concluded that there is a supermassive black hole that is dense enough to cause these motions. Although the black hole itself is invisible, we can still observe the ring of light bended by the gravitational lensing. A telescope of the size of the Earth is needed in order to take a picture of the light 55 million light years away, but scientists managed to combine images taken from eight observatories around the globe.
As the Earth rotates, telescopes in these locations are able to observe different part of the image. The researchers then developed imaging algorithms that can fill in the missing gaps in the measurements, “just as a forensic sketch artist uses limited descriptions to piece together a picture using their knowledge of face structure. (How to take a picture of a black hole-Katie Bouman)”
On April 10th, the first picture of a black hole was finally released by the Event Horizon Telescope team. This supermassive black hole 6.5 billion times more massive than the Sun was named Powehi (Po-veh-hee), which refers to “the adorned fathomless dark creation” or “embellished dark source of unending creation.” This image provides the strongest evidence of existence of black holes for the first time. It also confirms the prediction of the shape and glow of a black hole based on Einstein’s general relativity—Einstein is proved right again.