A Black Hole Finally (Un)Seen in the Centre of a Galaxy:The Sharpest Image Ever
The uneven ring of radio emission at the centre of the distantgalaxy,M87, has excited astronomers, physicists, and thegeneral public, as the first view of a black hole. Everythingabout the project, known as the EHT – Event Horizon Telescope
– is extreme. The observation combines signals fromradio telescopes distributed over an entire hemisphere, operatingat millimetre wavelengths on high mountains and atthe Earth’s poles. These telescopes are synchronised by thebest atomic clocks, and massive amounts of data recordingand number crunching were needed. To interpret the results,elaborate models of the energy source, based on Einstein’sgeneral theory of relativity (GTR) were constructed.The team had over three hundred scientists from more thana hundred institutions, some of whom worked for nearly adecade towards this goal.