Astronomers announced on Wednesday that at last they had observed the unobservable: a black hole, a cosmic abyss so deep and dense that not even light can escape it.
For years, computer modelers and artists have envisaged black holes realistic enough to satisfy cosmic researchers and “Star Trek” fans alike. But nothing compares to an actual image of the dark creature.
“We have seen what we thought was unseeable,” said Shep Doeleman, an astronomer at the Harvard-Smithsonian Center for Astrophysics, and director of the effort to capture the image, during a Wednesday news conference in Washington, D.C.
The image, of a lopsided ring of light surrounding a dark circle deep in the heart of the galaxy known as Messier 87, some 55 million light-years away from Earth, resembled the Eye of Sauron, a reminder yet again of the implacable power of nature. It is a smoke ring framing a one-way portal to eternity.
To capture the image, astronomers reached across intergalactic space to Messier 87, a giant galaxy in the constellation Virgo. There, a black hole several billion times more massive than the sun is unleashing a violent jet of energy some 5,000 light-years into space.
“This is a remarkable achievement,” said Shep Doeleman, an astronomer at Harvard University. The image provides visual evidence that black holes exist.
Event Horizon Telescope Collaboration, via National Science Foundation
The image offered a final, ringing affirmation of an idea so disturbing that even Einstein, from whose equations black holes emerged, was loath to accept it. If too much matter is crammed into one place, the cumulative force of gravity becomes overwhelming, and the place becomes an eternal trap, a black hole. Here, according to Einstein’s theory, matter, space and time come to an end and vanish like a dream.
On Wednesday morning that dark vision became a visceral reality. As far as the Event Horizon team could ascertain, the shape of the shadow is circular, as Einstein’s theory predicts.
It would have been easy for the theory to come out wrong, said Avery Broderick of the Perimeter Institute for Theoretical Physics in Waterloo, Ontario: “In April 2017, this was the dog that did not bark.”
The results were announced simultaneously at news conferences in Washington, D.C., and five other places around the world, befitting an international collaboration involving 200 members, nine telescopes and
six papers for the Astrophysical Journal Letters. When the image was put up on the screen in Washington, cheers and gasps, followed by applause, broke out in the room and throughout a universe of astrofans who were following the live-streamed event.
“Einstein must be totally chuffed,” said Priyamvada Natarajan, an astrophysicist at Yale. “His theory has just been stress-tested under conditions of extreme gravity, and looks to have held up.”
Kip Thorne, an astrophysicist at the California Institute of Technology, and who shared a Nobel Prize in 2017 for the discovery of gravitational waves from colliding black holes, wrote in an email: “It is wonderful to see the nearly circular shadow of the black hole. There can be no doubt this really is a black hole at the center of M87, with no signs of deviations from general relativity.”
Janna Levin, a cosmologist and professor at Barnard College in New York, said, “What a time to be alive.”
A telescope the size of Earth
The image emerged from two years of computer analysis of observations from a network of radio antennas called the Event Horizon Telescope. In all, eight radio observatories on six mountains and four continents
observed the galaxy in Virgo on and off for 10 days in April 2017.
The telescope array also monitored a dim source of radio noise called Sagittarius A* (pronounced Sagittarius A-star), at the heart of our Milky Way galaxy. There, 26,000 light-years from Earth, and buried in the depths of interstellar dust and gas, lurks another black hole, with a mass of 4.1 million suns.
The network is named after the edge of a black hole, the point of no return; beyond the event horizon, not even light can escape the black hole’s gravitational pull.
The image provided astrophysicists with the first look at the innards of a black hole and a mystery that has tantalized astronomers for more than half a century.
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