Hello Darkness, our old friend, we have come to see you again.
At the center of Messier 87, a giant galaxy 55 million light-years from Earth, there is a darkness more than 38 billion kilometers across and as massive as 6.5 billion suns, an opening to infinity called a black hole.
In 2017, a group of astronomers was operating the Event Horizon Telescope, an array of antennas covering the globe, when they produced an image of the black hole in Messier 87, or M87, the first of any black hole. The image revealed a ring of hot gas, slightly tilted, swirling around a dark void like water running in circles around a sink, just as Albert Einstein's theory of general relativity predicted in 1915. When the image was revealed in 2019, it made front-page media coverage. the world. It is now in the collection of the Museum of Modern Art in New York.
Now, the same team of scientists has done it again, albeit in a better way. In 2018, a year after the first image was taken, astronomers again looked into the darkness of M87 using a slightly expanded grid that provided greater resolution. The results were published last week in Journal of Astronomy and Astrophysicsshows the same irregular ring and central hole in more substantial detail, suggesting that astronomers got things right the first time.
“The first image of a black hole looked so much like mathematical predictions that it seemed like a coincidence,” Dominic Chang, a doctoral candidate in physics at Harvard University who works on the Event Horizon team, said in an article. press release Issued by the Center for Astrophysics at Harvard University and the Smithsonian in Cambridge, Massachusetts, where the project is based.
“Having the opportunity to conduct new tests using new data, using a new telescope, and seeing the structure itself, is a crucial confirmation of our most important conclusions,” he said.
A change has occurred in the ring surrounding the black hole M87. Its shiny knot has moved about 30 degrees counterclockwise around the ring from where it was a year ago. Astronomers said they expected the hot spot to move.
“Although general relativity says the size of the ring should remain fairly constant, the emission from the turbulent, irregular accretion disk around the black hole will cause the brightest part of the ring to wobble around,” said Brett Jeter, a postdoctoral researcher. Common centre. At the Academia Sinica Institute of Astronomy and Astrophysics in Taiwan, per the press release. “The amount of fluctuation we see over time is something we can use to test our theories about the magnetic field and plasma environment around the black hole.”
“In other words, the M87 supermassive black hole is behaving exactly as we thought,” Shepard Doeleman, a researcher at the Center for Astrophysics and founding director of the Event Horizon Collaboration, added in an email.
For Einstein, black holes were one of many problematic predictions that arose from general relativity, which attributed what we call gravity to warping in the geometry of space-time. The first is that the universe was expanding. Another reason was that if too much matter or energy was concentrated within a certain radius – now called the event horizon – it would collapse forever into a gap in space-time from which not even light could escape.
Einstein agreed with mathematics, but he believed that nature would find a way not to create such excess. But scientists now know that the universe is full of black holes; Experiments like the Laser Interferometry Observatory for Gravitational Waves, or LIGO, have heard them colliding with each other, and the Event Horizon Telescope has turned them into reality. Many black holes are dead stars that collapsed when they ran out of thermonuclear fuel, but a giant black hole with millions or billions of times the mass of an ordinary star appears to be at the center of most galaxies. Astronomers still don't know how it came into existence.
Thanks to a quirk of nature, two of these supermassive black holes — in M87 and at the center of our Milky Way Galaxy — are large enough in the sky to be imaged and studied by the Event Horizon Telescope. An image of our black hole, called Sgr A*, which lies 27,000 light-years from Earth in the direction of the constellation Sagittarius, has appeared for the first time in 2022.
We can expect more of these images of fate. Doleman and his team plan to continue adding them to their network and eventually create a movie about black holes. Die of envy, Netflix!
Dennis Overbye is the Times's outer space correspondent and also covers physics and astronomy. More from Denise Overby
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