It wasn't the first picture of a black hole this collaboration had captured-that was the iconic image of M87*, which they revealed in April 2019. This past spring, however, the astronomers behind the Event Horizon Telescope (EHT) settled the matter by unveiling the first image of a supermassive black hole at the center of the Milky Way. For example, when astronomers Reinhard Genzel and Andrea Ghez shared a portion of the 2020 Nobel Prize in Physics, their citation specified that they were awarded for “the discovery of a supermassive compact object at the centre of our galaxy,” not the revelation of a “black hole.” The object is known as Sagittarius A* (“Sagittarius A star”). Scientists have long thought that only a supermassive black hole could explain the stars' movements, but until this year, they hesitated to say that outright. This is a place where stars slingshot around apparently empty space at an appreciable fraction of the speed of light. Hence, each morning I would come to work to find about 100 overnight emails from colleagues – a daunting start to any day.Īnyway, we got there in the end – and the dazzling result was worth all of the work.Deep in the heart of the Milky Way, strange things happen. Since the majority of the collaborators are based in either the US or East Asia, it meant that they were working during the night in UK time. I also had to channel comments from my colleagues. This had its challenges, as I had to deal with every typo and every mistake in the typesetting. This is an administrative role, in which I handled all correspondence between our team of over 300 astronomers and the academic journal that published our findings. In addition, I was a “contributing author” for all six papers. My role was to help write two of the six papers that have been released in the Astrophysical Journal Letters: the first one, introducing the observation and the third one, in which we discuss how we made a picture out of the observations, and how reliable that image is. So online meetings became the norm, as in every other aspect of life. Then COVID struck and suddenly nobody could go anywhere. To begin with we were meeting face to face in different parts of the world. We had a lot of meetings to come to a consensus of what it tells us. I couldn’t wait to start writing about it and interpreting the image. When I first saw the image, I thought: this tells us a lot. The publication of the picture of the Sagittarius A* black hole is a tremendously exciting achievement by the collaboration. I think even Einstein himself might have been surprised by that! Relativity has been around for a century and it is still proving to be accurate. Both of them obey Einstein’s theory of general relativity, showing Einstein was right for a factor of 1,000 in size scale. The reason for the similarity is that while the M87* black hole is about 1,000 times bigger, the Sagittarius black hole is about 100 times closer. The surprising thing about this image is that it looks so similar to the image of M87* we published three years ago – this certainly came as a surprise. The breakthrough follows the collaboration’s 2019 release of the first ever image of a black hole, called M87*, at the centre of the more distant Messier 87 galaxy.ĪLMA – one of the Event Horizon telescopes. Our team was part of the global Event Horizon Telescope (EHT) Collaboration, which has used observations from a worldwide network of eight radio telescopes on our planet – collectively forming a single, Earth-sized virtual telescope – to take the stunning image. Sagittarius A* also seems rather inactive – it is not devouring a lot of matter from its surroundings. In fact, because the black hole is so far away from Earth, it appears to us to have about the same size in the sky as a donut would have on the Moon. While it might seem a little scary to be so close to such a beast, it is in fact some 26,000 light-years away, which is reassuringly far. This means there is now overwhelming evidence for the black hole, dubbed Sagittarius A*. But now an international team of astronomers, including a team that I led from the University of Central Lancashire, has unveiled the first image of the object lurking at the centre of the Milky Way – and it is a supermassive black hole. There are other ideas too – such as “dark matter” (an invisible substance thought to make up most of the matter in the universe). In fact, most physicists have suspected that our own galaxy revolves around a supermassive black hole at its centre. Originally studied as a mere mathematical consequence of the theory rather than as physically relevant objects, they soon became thought of as generic and sometimes inevitable outcomes of the gravitational collapse that initially forms a galaxy. Black holes are among the most profound predictions of Einstein’s theory of general relativity.
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