Black holes pack an immense amount of mass into a surprisingly small space. At that specific radio frequency, radiation can penetrate the haze of dust and gas that surrounds the centers of galaxies.īut zooming in on the black holes was still a challenge. The EHT team, from 13 institutions around the world, made its observations of M87* and the black hole at the center of our Milky Way, known as Sagittarius A* (Sgr A*), over 5 nights in April 2017 using eight radio telescopes that are sensitive to wavelengths of about a millimeter. The observed shadow is essentially circular, Broderick says.ĭata from the South Pole Telescope, one of the radio dishes used in the Event Horizon Telescope, overwintered in Antarctica before being combined with other data. General relativity predicts that the shadow ought to be round to within 10%, says Avery Broderick, an EHT member and astrophysicist at the University of Waterloo in Canada, whereas alternative theories of gravity predict distorted, noncircular shapes. The black hole bends light around it, creating a circular shadow. In the team's images, the bottom of the ring appears bright because the gases there are being Doppler-boosted, whipped toward Earth.

As they consume matter that strays too close, they squeeze it into a superheated disk of glowing gas. Black holes have gravitational fields so strong that even light cannot escape, so they are defined by the shell of a black, featureless sphere called an event horizon. 'This is the end of space and time.' Falcke says the 2-year process of crunching the data and generating the images 'was the most emotionally difficult period of my life.'Īlthough few doubted the existence of black holes, seeing them-or at least their shadow-was an immense challenge. 'It feels like looking at the gates of hell,' says Heino Falcke of Radboud University in Nijmegen, the Netherlands, one of the leaders of the Event Horizon Telescope (EHT) collaboration, which announced the result in a global set of coordinated press conferences. It is also a feat for the team of more than 200 scientists who toiled for years to produce the image by combining signals from eight separate radio observatories spanning the globe. The result-a ring of fire surrounding the blackest of shadows-is a powerful confirmation of Albert Einstein's theory of gravity, or general relativity, which was used to predict black holes 80 years ago.

Astronomers today revealed a picture of the gargantuan black hole at the heart of the nearby galaxy Messier 87 (M87). At last, we can see it: a black hole in the flesh.

Real black hole picture