Yesterday, the world saw a black hole for the first time when an international team of researchers from the Event Horizon Telescope project unveiled the image of a massive black hole at the center of galaxy Messier 87 (M87). The image displays a dark disc "outlined by emission from hot gas swirling around it under the influence of strong gravity near its event horizon," the consortium said.
"As an astrophysicist, this is a thrilling day for me," said National Science Foundation Director France A. Córdova.
The giant black hole is roughly 55 million light-years from Earth in the Virgo galaxy cluster, with a mass some 6.5 billion times that of the sun. "We are delighted to be able to report to you today that we have seen what we thought was unseeable. We have seen and taken a picture of a black hole," said EHT Director Shep Doeleman of Harvard University.
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Researchers at the Event Horizon Telescope project were able to capture an image of a black hole by using a network of eight radio telescopes to create "a virtual telescope dish as large as the Earth itself," the National Science Foundation said.
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You are looking at the first ever image of a black hole, captured by the @ehtelescope Project. Within the dark spot is the black hole—a place so gravitationally dense nothing can escape from it, not even light. The orange halos surrounding the hole are hot gas emissions, swirling around it under the influence of the strong gravity near the event horizon—the point past which not even light can escape before falling into the void. To capture this image, a network of telescopes around the globe coordinated efforts to observe the black hole that sits at the center of Messier 87, a massive galaxy in the nearby Virgo galaxy cluster, 55 million light-years from Earth. This effort to create an “Earth-sized” telescope resulted in five petabytes of data (“the equivalent of billions of cat videos” according to EHT researchers) which researchers refined to create this historic first image. The National Science Foundation played a pivotal role in this discovery by funding individual investigators, interdisciplinary scientific teams and radio astronomy research facilities since the inception of EHT. Over the last two decades, NSF has directly funded more than $28 million in EHT research, the largest commitment of resources for the project #RealBlackHole #ehtblackhole
According to Doeleman, the breakthrough is the result of a decade of work to coordinate the many working parts of the project and obtain the highest resolution possible from Earth. Exactly two years ago "all of the dishes in the Event Horizon Telescope swiveled, turned and stared" at the core of M87. The image was captured from that data.
"You have probably seen many, many images of black holes before," said Heino Falcke, a professor in the Netherlands who chairs the EHT Science Council. "But they were all simulations or animations. And this [image] is precious to all of us because this one is finally real."
At the European Research Council's news conference in Brussels, Falcke said that the image "looks like a ring of fire. And it's actually created by the force of gravity, by the deformation of space-time, where light actually goes around the black hole, almost in a circle."
In Washington, Doeleman added, "The bright patch in the south ... tells us that material moving around the black hole is moving at light speeds — which is also consistent with our simulations and predictions" based on Albert Einstein's theories.
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In a historic feat by the Event Horizon Telescope and National Science Foundation (@NSFgov), an image of a black hole and its shadow has been captured for the first time. Several of our missions were part of a large effort to observe the same black hole using different wavelengths of light and collect data to understand the black hole's environment. Here's a look at @NASAChandraXRay Observatory's close-up of the core of the M87 galaxy and the black hole at the center of it. Credits: NASA/CXC/Villanova University/J. Neilsen #blackhole #EHTblackhole #galaxy #first
The image proves a theory that scientists have had for years. "We now know clearly that black holes drive large-scale structure in the universe," Doelman said. "As with all great discoveries, this is just the beginning."
The black hole, which is approximately 100 billion kilometers across, is not visible to the human eye. The hole's gravity is so intense that light cannot escape its center. The accretion disk that surrounds the hole is a swirl of gas and material. "Black holes are the X-games of physics. They represent an unexplored extreme of space-time," astrophysicist Adam Frank wrote for NPR in 2017. "While we now have good indirect evidence that they exist, getting a direct view of a black hole is the ultimate dream for a lot of physicists."
There are EHT telescopes located around the world, from Antarctica to Arizona and from Mexico to Spain. The analysis of data is a painstaking process with each signal received by the telescopes synchronized wave by wave, using atomic clocks and a supercomputer to compare and combine observations from around the globe. "Like a time-lapse exposure, this slowly builds up an image of even a very dim source," the NSF says. "It also allows Earth's rotation to, in effect, fill in the empty spaces in the array to produce a more complete picture."
In just a few weeks of viewing the black hole, the EHT project collected 5 petabytes of data, which Dan Marrone of the University of Arizona said was equal to 5,000 years' worth of mp3 files — or "the entire selfie collection over a lifetime for 40,000 people."
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Shimmering like gems strewn across the sky, this cluster of stars is one of the largest of its kind. 🌟 Messier 2 is a spherical group of stars tightly bound together by gravity. The globular cluster is populated with 150,000 stars and is located 55,000 light-years away in the constellation of Aquarius. It is captured by the one and only @NASAHubble. Image credit: ESA/Hubble & NASA, G. Piotto et al. #Space #MilkyWay #NASA #Astronomy
At MIT's Computer Science and Artificial Intelligence Lab in Massachusetts, computer scientist Katie Bouman "led the creation of a new algorithm to produce the first-ever image of a black hole," the lab said yesterday. Bouman discussed in 2016 the challenge of using algorithms to "piece together pictures from the sparse, noisy data" from telescopes.
To find a black hole that would be visible from Earth, Event Horizon researchers centered on "supermassive" black holes found at the centers of galaxies. The international collaboration decided to focus on the black hole at the center of galaxy M87 because of its size, among other things. "M87 is the nearest galaxy with a supermassive black hole that's generating a powerful jet — a beautiful streamer made of plasma traveling at close to the speed of light," said Charles Gammie, a professor at the University of Illinois at Urbana-Champaign who is on the EHT Science Council Board.
"One of the great mysteries in astronomy has been how such jets are launched. Our simulations, which are based on the motion of magnetic fields and hot gas near the black hole, showed that the jets are powered by the black hole itself. Magnetic fields act to brake the rotation of the black hole and transfer its rotational energy to the jet," Gammie added.
As they examined the image and the data, astronomers were able to confirm many of the theories about the workings of the universe. "Once we were sure we had imaged the shadow, we could compare our observations to extensive computer models that include the physics of warped space, superheated matter, and strong magnetic fields. Many of the features of the observed image match our theoretical understanding surprisingly well," said Paul T.P. Ho, EHT board member and director of the East Asian Observatory. "This makes us confident about the interpretation of our observations, including our estimation of the black hole's mass."