Astronomers reveal first image of black hole at the heart of our Milky Way galaxy
Berlin, May 12: Astronomers on Thursday unveiled the first image of the supermassive black hole at the centre of our own Milky Way galaxy.
The finding, published in The Astrophysical Journal Letters, provides overwhelming evidence that the object is indeed a black hole and yields valuable clues about the workings of such giants, which are thought to reside at the centre of most galaxies.
The image was produced by a global research team called the Event Horizon Telescope (EHT) Collaboration, using observations from a worldwide network of radio telescopes.
The finding was unveiled during simultaneous press conferences around the world, including at the European Southern Observatory (ESO) headquarters in Germany.
The image is a long-anticipated look at the massive object that sits at the very centre of our galaxy. Scientists had previously seen stars orbiting around something invisible, compact, and very massive at the centre of the Milky Way.
This strongly suggested that this object known as Sagittarius A* (Sgr A* ) is a black hole, and the image provides the first direct visual evidence of it.
Although we cannot see the black hole itself, because it is completely dark, glowing gas around it reveals a tell-tale signature: a dark central region (called a shadow) surrounded by a bright ring-like structure, the researchers said.
The new view captures light bent by the powerful gravity of the black hole, which is four million times more massive than our Sun, they said.
We were stunned by how well the size of the ring agreed with predictions from Einstein's Theory of General Relativity," said EHT Project Scientist Geoffrey Bower from the Institute of Astronomy and Astrophysics, Academia Sinica, Taipei.
"These unprecedented observations have greatly improved our understanding of what happens at the very centre of our galaxy, and offer new insights on how these giant black holes interact with their surroundings," Bower said.
Because the black hole is about 27 000 light-years away from Earth, it appears to us to have about the same size in the sky as a doughnut on the Moon.
To image it, the team created the powerful EHT, which linked together eight existing radio observatories across the planet to form a single Earth-sized virtual telescope.
The EHT observed Sgr A* on multiple nights in 2017, collecting data for many hours in a row, similar to using a long exposure time on a camera.
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England sticking with Key, McCullum and Stokes despite Ashes humbling
London (AP): England is not sacking anybody following the 4-1 Ashes loss in Australia.
A review of the tour by the England and Wales Cricket Board, announced within hours of the final match in January, was concluded on Monday. Firing people would “be the easy thing to do,” ECB chief executive Richard Gould said but he insisted, "This is not the time to throw everything out."
Managing director Rob Key, coach Brendon McCullum and captain Ben Stokes kept their jobs after the best England side to go to Australia in 14 years lost the Ashes in 11 days with two games to spare.
“Moving people on can sometimes be the easy thing to do. That's not the route that we're going to take,” Gould said. “I've seen the driving ambition and determination that we're lucky enough to have within our leadership group to take the lessons from the Ashes and move forward.”
Gould previously was the chief executive of Bristol City soccer club and said the ECB would not follow the same route as soccer's hire-and-fire culture.
“Cricket is a very unique sport in that it takes a team of leadership ... it's not like football where there's a single point of failure or success with a manager," he said. He added the ECB would not “select or deselect management based on a popularity campaign.”
The main criticisms of England's tour were poor preparation, player misbehavior, and selection mistakes.
At a press conference at Lord's, Gould and Key said McCullum and Stokes have not had a “bust up,” they did not want McCullum to “completely change” but “to evolve,” the behavior of some players was “unprofessional,” there will be more consequences for underperforming, and a commitment to “better long-term planning” ahead of major test series.
Some changes were already implemented for the Twenty20 World Cup, where England reached the semifinals. Gould implied that performance saved McCullum.
Key acknowledged that England supporters would be disappointed to see the management team go unpunished.
“I know people want punishment and that people then should be sacked for that,” Key said. “That doesn't mean we don't feel like we've gone through some serious pain: Brendon, myself, Ben. It's been as tough a time as I think I've had.”
