Scientists have obtained the first image of a black hole, using Event Horizon Telescope observations of the center of the galaxy M87.
The image shows a bright ring formed as light bends in the intense gravity around a black hole that is 6.5 billion times more massive than the Sun. This long-sought image provides the strongest evidence to date for the existence of supermassive black holes and opens a new window onto the study of black holes, their event horizons, and gravity.
The image is the result of a colossal, years-long effort by dozens of researchers. To find it, the EHT focused on a pair of supermassive black holes — the one at the center of the Milky Way galaxy, known as Sagittarius A* (pronounced Sagittarius A-star), and a second that lies at the heart of an elliptical galaxy called M87.
Capturing an image of a black hole, project leaders said, is about more than getting the first glimpse of one of the most curious objects in the cosmos. It also opens the door to allowing astronomers and physicists to test Einstein’s theories of gravity and general relativity under the most extreme conditions in the universe.
“A black hole, if you looked at it naked … would be invisible,” said Sheperd Doeleman, director of the EHT. “It’s nature’s most amazing invisibility cloak.”
So how do you take a picture of something from which even light cannot escape?
“In a paradox of its own gravity,” Doeleman explained, “you wind up seeing it because all the gas and dust that’s attracted to it gets crushed into a smaller and smaller volume, causing it to heat up to hundreds of billions of degrees. So you wind up with a 3-D flashlight illuminating all the space-time around the black hole.”