An international team of more than 200 people spent more than a decade working to capture the image (seen above) released today. Astronomers have been trying to directly image a black hole, but imaging something that is so far off and essentially invisible requires some out-of-the-box thinking. Enter the EHT, a collection of eight telescopes that span the globe.
Instead of having a single telescope that measures perhaps a few metres or tens of metres across, astronomers now have telescopes that work in unison and become “Earth-sized.” This allows astronomers to collect data that provides an image of the black hole, though with some missing data.
“We’ve now seen the unseeable,” said Avery Broderick, a physicist at the University of Waterloo and the Perimeter Institute who was part of the international EHT research team. “Black holes are made real — they’re not just the scribblings on theorists’ chalkboards anymore, but they really are out there in the night.”
The image, which shows an orange ring around a round, black silhouette, is of the black hole at the centre of Messier 87 (M87), a galaxy 50 million light-years from Earth. This black hole is one of the most massive known: it’s six billion times more massive than our sun.
Black holes are so dense and have such strong gravity that anything that crosses their threshold – known as the event horizon – gets pulled into them, never to return. That includes both matter and light, making them black and invisible — and therefore very difficult to see and photograph.
Image source: https://news.harvard.edu/gazette/story/