Scientists using the Event Horizon Telescope have successfully unveiled the first-ever image of a supermassive black hole and its shadow April 10.
The Event Horizon Telescope — an array of eight ground-based radio telescopes made possible by international collaboration — captured this image studying the Messier 87 galaxy. The black hole is about 6.5 billion times the size of the sun and is about 55 million lightyears away from Earth. The discovery was published in a series of six papers published in The Astrophysical Journal Letters.
“We have taken the first picture of a black hole,” said EHT project director Sheperd S. Doeleman of the Center for Astrophysics, Harvard & Smithsonian. “This is an extraordinary scientific feat accomplished by a team of more than 200 researchers.”
The image shows a blurry, bright ring around a black circular figure, but the image shows something more than just a dark, smudgy region. According to the EHT’s notes, the shadow of a black hole was the closest they could come to an actual image of the black hole itself. Black holes are a completely dark object from which light cannot escape, according to the EHT.
“The black hole’s boundary — the event horizon from which the EHT takes its name — is around 2.5 times smaller than the shadow it casts and measures just under 40 billion km across,” the EHT team wrote.
“If immersed in a bright region, like a disc of glowing gas, we expect a black hole to create a dark region similar to a shadow — something predicted by Einstein’s general relativity that we’ve never seen before, explained chair of the EHT Science Council Heino Falcke of Radboud University, the Netherlands. “This shadow, caused by the gravitational bending and capture of light by the event horizon, reveals a lot about the nature of these fascinating objects and allowed us to measure the enormous mass of M87’s black hole.”
For the scientists to capture this image, it took multiple calibration efforts to reveal the black hole’s ring-like structure.
“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.”
According to the EHT team, making this telescope possible was a worldwide effort that consisted of finding the perfect high-altitude site. They looked at locations in volcanoes in Hawaii and Mexico, mountains in Arizona and the Chilean Atacama Desert, and even Antarctica. The effort of creating this image took decades in the making of observation, technical and theoretical work, according to the EHT team. The culmination of this image came from 13 partner institutions working together with funding provided by the U.S. National Science Foundation, the EU’s European Research Council and funding agencies in East Asia.
“We have achieved something presumed to be impossible just a generation ago,” Doeleman said. “Breakthroughs in technology, connections between the world’s best radio observatories, and innovative algorithms all came together to open an entirely new window on black holes and the event horizon.”
What is a black hole?
A black hole is an area of space where the gravitational vacuum is so strong that nothing can escape – this area of spacetime essentially ‘swallows’ everything from light to particulate matter leaving no opportunity for for escape from the event horizon.
Black holes are created when a very large star reaches the end of it’s life cycle and collapses in on itself. As a black hole continues to swallow up floating mass surrounding it, it continues to grow in size.
Source: The Astrophysical Journal Letters, eventhorizontelescope.org