The ‘glowing doughnut’ which proves Einstein was right
The glowing doughnut lost in the vastness of space looks harmless enough – but it is just as well the object is 55 million light years away.
This is the first image astronomers have captured of a supermassive black hole big enough to swallow stars at the centre of a distant galaxy.
Nothing that gets too close to the monstrous gravitational vortex can ever escape – not even light.
But at the “point-of-noreturn” precipice around its edge – the boundary scientists call the Event Horizon – hot gas, matter and radiation rage in a swirling eddy.
While a black hole itself is by its nature invisibly dark, astronomers can observe the Event Horizon maelstrom with sufficiently powerful instruments.
The image of the supermassive black hole at the core of galaxy M87 was obtained by combining eight radio dishes around the world into one global telescope.
It shows a thick ring of light surrounding a dark centre.
Nothing like this photo has ever been obtained before. Previously, scientists have only been able to visualise black holes in simulations.
In 2012 astronomers from Johns Hopkins University in the US published images of a black hole 2.7 million light years away gobbling up a Red Giant star – but it was nothing more than a tiny smudge of light.
At one of six press conferences around the world announcing the landmark results from the Event Horizon Telescope project, Dr Sheperd Doelman, from Harvard University in the US, said: “We have seen what we thought was unseeable. We have seen and taken a picture of a black hole.
“This is a remarkable achievement. We now have visual evidence of a black hole. This is the strongest evidence that we have to date of the existence of black holes.”
The EHT radio telescopes were also pointed at a supermassive black hole at the centre of our own galaxy, the Milky Way – an energy source known as Sagittarius A (Sgra).
Prior to the announcement there had been speculation that images of Sgra would provide the most dramatic results.
But in fact it was the M87 black hole that stole the show. The size of the object almost defies the imagination – it contains 6.5 billion times more mass than the sun.
Scientists gathered at the National Press Club in Washington DC explained that Sgra was a “complex” object and the M87 black hole had been easier to image.
They said they were hoping to release photos of Sgra soon but could make “no promises”.
The network of radio telescopes used to capture the image included dishes in Hawaii, Mexico, Spain, Chile and Antarctica.
Astronomers used a technique called very-long-baseline interferometry (VLBI) to synchronise the telescopes together.
Acting as one, they achieved a level of angular resolution equivalent to reading a newspaper in new york from a pavement cafe in Paris, France.
The dark centre of the glowing “doughnut” is in fact a shadow caused by the gravitational bending of light.
M87’s black is actually 2.5 times smaller than the shadow it casts.
A British scientist involved in the project, Dr Ziri Younsi from the University College London Mullard Space Science Laboratory, said: “We have accomplished something many thought impossible by imaging the shadow of a black hole and it provides the strongest evidence to date that such evasive and enigmatic entities do indeed exist.”
“We now have visual evidence of a black hole. This is the strongest evidence that we have to date of the existence of black holes”
DR SHEPERD DOELMAN
Along time ago in a galaxy far, far away, there was an “absolute monster”. This wasn’t a scary fictional alien from Star Wars, but a very real black hole, the first ever to have its picture taken by astronomers.
It may be huge at three million times the size of the Earth, but given the hole is an extraordinary 500 million trillion kilometres away, it was quite a feat to be able to capture an image of its shadow and the fiery disc of material around it – and one considered impossible until recently. It was only accomplished because of collaboration on a global
scale involving more than 200 researchers and eight telescopes – including the James Clerk Maxwell telescope, named after the Scottish physicist, in Hawaii and others in Arizona, Spain, Mexico, Chile and Antarctica. These were linked together to form one “Earth-sized” telescope so powerful that it could theoretically read a newspaper in New York from as far away as Paris.
It is evidence, if it were needed, that together we are stronger, that international collaboration and indeed “globalisation”, a dirty word to some, can help us do great things, even achieve the impossible.