Astrophysicists think there's a supermassive black hole at the center of the Milky Way galaxy. It's supposed to be four million times more massive than our Sun, but despite its stupendous size, we've never been able to see it. That might soon change. The European Research Council has given 14 million euros ($19.3 million) to the creators of BlackHoleCam, a project that will use radio telescopes and supercomputers to try to prove the existence of what Luciano Rezzolla, a principal investigator for BlackHoleCam, calls "one of the most cherished astrophysical objects."
BlackHoleCam's name is slightly misleading. It won't be able to image the black hole itself, instead using the event horizon that it expects to see to confirm the hole's existence. The event horizon — a phenomenon predicted by Einstein — is the boundary of spacetime beyond which the pull of gravity is so great that escape is impossible. Space.com reports the Milky Way's black hole should betray its event horizon by casting "a dark shadow" over bright radio wave emissions given off as gas is pulled into the black hole.
BlackHoleCam will try to image the black hole's event horizon to confirm its existence
The project will use an approach called Very Long Baseline Interferometry, in which multiple observatories — including Chile's new ALMA telescope — are focused on one object, pulling in data that's then fed through a supercomputer. BlackHoleCam will also work closely with the Event Horizon Telescope, an American-led group who also use VLBI in their efforts. As befitting an object so large our entire galaxy spins around it, we have to use something the size of a planet to see it: Space.com says by using Very Long Baseline Interferometry, BlackHoleCam turns the Earth itself into a vast virtual telescope.