The excitement was palpable, the language almost biblical. ‘We have seen what we thought was unseeable,’ Dr Sheperd Doeleman announced in Washington DC. ‘We have seen and taken a picture of... a black hole.’
And there it was, a black disc surrounded by a golden ring — particles of light known as photons, emitted by a swirling mass of ultra-hot plasma gas.
This ring surrounds the black hole’s ‘event horizon’, the boundary beyond which nothing, not even light, can escape its gravitational grip.
It is an image that has the world’s leading space scientists and physicists in a fever of excitement — and with good cause.
Until now, all our knowledge about black holes has existed only in the realms of theory. Now, we have an image of a ‘supermassive’ black hole, 55 million light years away — one light year is equivalent to almost six million million miles — and big enough to pull in and crush stars and planets.
From its maw, it spews out hot gases in jets that stretch for 5,000 light years into the cosmos.
It lies at the heart of a vast galaxy known as M87, part of the Virgo Cluster — a watermelon-shaped collection of thousands of galaxies that move through space together.The black hole is as wide as three million planet Earths and 6.5 billion times as dense as our Sun.
It was Albert Einstein who, in 1915, first produced the calculations that predicted the existence of black holes, and in the 1930s U.S. physicist Robert Oppenheimer developed the idea further.Such entities would be created when a giant object such as a star collapsed under the pull of its own gravity and was compressed into a minute, massively dense object known as a ‘singularity’.
In the singularity, the normal laws of physics would no longer apply and its infinitely strong gravity would suck in even light, so all that could be seen would be a black hole — which, of course, would be impossible to photograph.But scientists soon realised that the cosmic dust and swirling mass of ultra-hot plasma gas around a black hole — if such a thing existed — would give off radiation that could be detected from Earth. This radiation is incredibly faint by the time it reaches us: the effort to detect it has been compared to trying to read a newspaper in Paris while standing in New York.But now these glimmers have been detected. It has taken seven years, 200 scientists and about £40 million to capture them.No single radio telescope was big enough, so eight banks of radio telescopes — in Hawaii, Antarctica, Chile, Mexico, Arizona, France, Greenland and Spain — were trained on the suspected site of the black hole.
Collectively, they operate like a single instrument — one so powerful that it could read the lettering on a 10p coin in London from 2,174 miles away in Cairo.Data from all the telescopes was pooled by a supercomputer, in effect creating one giant telescope — the Event Horizon Telescope.
No single radio telescope was big enough, so eight banks of radio telescopes — in Hawaii, Antarctica, Chile, Mexico, Arizona, France, Greenland and Spain — were trained on the suspected site of the black hole
Dr Doeleman said it had now provided ‘the strongest evidence we have to date of the existence of black holes.’But amid the cheering, one can imagine the ghostly voice of Einstein saying: ‘Dammit!’These singularities — later dubbed black holes — are gravity wells so strong that, once entered, you are instantly beyond the point of no return.
Einstein found the theory so bizarre, he wrote a paper in 1939 refuting it. But as the years passed, researchers across the world found more and more clues to support Schwarzschild’s idea.