Team led by Heino Falcke presents the first photograph of a black hole
The first photograph of a black hole has been published, providing the first tangible proof that black holes exist. In Brussels, a team of astronomers led by Nijmegen-based Professor Heino Falcke presented the long expected accomplishment this afternoon.
And here it is: the long-awaited photograph of a black hole. At the European Commission headquarters in Brussels, Heino Falcke, the lead researcher on the project, explained the images. The photographs were presented simultaneously at press conferences in the United States, Chile, China, Taiwan and Japan.
A week earlier, a visibly nervous Heino Falcke said ‘I’ve never had such a large live audience’, while recalling the first time he had the idea of photographing a black hole – or more correctly – photographing the outline of a black hole. At that time, almost 20 years ago, he was working at the Max Planck Institute in Bonn, Germany. ‘I was busy trying to understand black holes. I just combined one and one,’ he says in his office on the second floor of the Huygens Building.
‘I just combined one and one’
It took ten years for fellow astronomers, who were sceptical about the feasibility of the plan, to support him. ‘Then it took another ten years to develop the technology.’ The funding was at least as important as the science. In 2013, Falcke received a grant of €14 million from the European Research Council to fund his Event Horizon Telescope project.
Collecting the data was not a simple task. ‘For this project we needed many hard disks that we had to deliver to telescopes all over the world. It was a hassle to get them to the right places on time, at locations such as the South Pole, Mexico, Greenland and Spain. And then all the hard disks had to be sent back, so we could combine all the data.’
And then came the most difficult part of the project came: keeping the results quiet. ‘If you ask me something, I am the type of person who simply answers the question. I don’t like confidentiality.’ In that regard, he did look forward to the press conference this afternoon. He could finally – at long last – make the news public. ‘In such a large collaboration – almost 200 researchers in total – everyone is constantly nervous. So much is at stake. Nobody wants the news to get out prematurely.’
The photograph of the black hole is already the second dream for Falcke to come true in a year. His other childhood dream, an antenna on the hidden side the moon, has recently become reality. ‘It is very hard when all your dreams come true, it really is emotionally exhausting. I understand this now.’ He laughs. ‘No, I really do. Making a dream come true takes an incredible amount of energy. It is very hard work.’
How do you take a picture of a black hole?
Taking a photograph of a black hole is challenging in many ways. First of all, black holes are far away. When viewed from the earth, they are extremely small. Even when they are relatively close to earth, like the one that the Event Horizon Telescope (EHT) has now photographed. That black hole is situated in the Virgo cluster, ‘just’ 55 million light years away. Its size on the night sky is smaller than a tea saucer on the moon as seen from the Earth.
You would think it would be impossible to make such photograph at such a distance, but the EHT managed to do it anyway. To this end, researchers linked telescopes together from all over the world: in the USA, Chile, Spain, Mexico and the South Pole. Exactly like a camera you use at home, the wider the lens of a telescope, the better you can zoom in. The interconnection between all the telescopes in the project has created a kind of virtual mega-telescope with a lens that is as wide as the Earth itself: 6,000 kilometres in diameter. With the mega-telescope, it is just barely possible to see the black hole. So don’t expect spectacular images like those in the science fiction film Interstellar.
The second problem is perhaps even more fundamental in nature: a black hole is called black for good reason. It is blacker than any object in the universe. Its gravity is so strong that not a single light particle can escape. All that we can see are the signals that just barely get away, which emerge outside the Event Horizon. Hence the name of the telescope.
Luckily, those escapees are clearly visible. According to Einstein’s theory of relativity and other theories, this ‘light’ should consist of radiation – radio signals – emitted by particles just before they cross the event horizon and fall into the black hole. It is precisely this radiation that is captured by the telescopes of the EHT. The researchers have digitally combined the radio signals from all the telescopes and then converted them into a ‘normal’ photograph.
Today, The Astrophysical Journal Letters published the scientific articles about the black hole. A live stream of the press conference in Brussels was shown at the science faculty in Nijmegen. Tomorrow, Vox also publishes a profile of astronomist Heino Falcke, as well as a report about the professor around his Brussels’ visit.