First-ever picture of a black hole unveiled
More than 50 million light-years away, in the heart of a giant elliptical galaxy called Messier 87, a gargantuan beast is devouring anything that strays too near. Stars, planets, gas, and dust—not even light escapes the monster’s grasp once it crosses a threshold called the event horizon.
Today, scientists unveiled an image of that object, a supermassive black hole containing the same mass as 6.5 billion suns. Resembling a circular void surrounded by a lopsided ring of light, this landmark image is the world’s first glimpse of a black hole’s silhouette, a picture that creeps right up to the inescapable edge of the black hole’s maw.
The new image is the stunning achievement of the Event Horizon Telescope project, a global collaboration of more than 200 scientists using an array of observatories scattered around the world, from Hawaii to the South Pole. Combined, this array acts like a telescope the size of Earth, and it was able to collect more than a petabyte of data while staring at M87’s black hole in April 2017. It then took two years for scientists to assemble the mugshot.
Before now, humans could only see indirect evidence that black holes even existed by looking for stars that seemed to orbit bizarre objects, by capturing radiation from the superheated matter swirling into them, or by seeing the extremely energetic jets of particles launched from their tumultuous environments. (Recently, astronomers caught their first glimpse of what seems to be a star becoming a black hole.)
“We’ve been studying black holes for so long that sometimes it’s easy to forget that none of us has ever seen one,” National Science Foundation director France Cordova said today during a press conference announcing the team’s achievement, held at the National Press Club in Washington, D.C.
“We are delighted to be able to report to you today that we have seen what we thought was unseeable,” added project director Shep Doeleman of the Harvard-Smithsonian Institute for Astrophysics. “What you are seeing is evidence of an event horizon … we now have visual evidence of a black hole.”
Six papers published today in the Astrophysical Journal Letters describe the observational tour de force, the process of achieving it, and the details that the image reveals. One of the chief takeaways is a more direct calculation of the black hole’s mass, which tracks closely with estimates derived from the motion of orbiting stars. The data also offer some hints about how some supermassive black holes manage to unleash gargantuan jets of particles traveling at near light-speed.
“It’s truly remarkable, it’s almost humbling in a certain way,” Doeleman says. “Nature has conspired to let us see something we thought was invisible.”