About 26,000 light years away, Sagittarius A* is probably not the closest black hole to Earth, but it is the closest supermassive one, with the mass of around 4 million Suns. That makes it the ideal target for astronomers looking to snap an image of a black hole. Of course, since light itself can’t escape the object’s gravitational pull, there’s not much to see on its own, but the goal is to see the “black hole shadow” – the silhouette of the object framed against the bright background of matter falling into the black hole.
But the problem is that since there’s half a galaxy between it and us, the light is scattered by all the matter in our line of sight, creating a bright cloud that obscures Sagittarius A*. To see through that, astronomers have now essentially used a virtual telescope the size of Earth.