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17 JULY-AUGUST 2022 ASTRO PUBLISHING dark, glowing gas around it reveals a telltale signature: a dark central region (called a shadow) sur- rounded by a bright ring-like struc- ture. The new view captures light bent by the powerful gravity of the black hole, which is four million times more massive than our Sun. “We were stunned by how well the size of the ring agreed with predic- tions from Einstein’s Theory of Gen- eral Relativity,” said EHT Project Scientist Geoffrey Bower from the Institute of Astronomy and Astro- physics, Academia Sinica, Taipei. “These unprecedented observations have greatly improved our under- standing of what happens at the very centre of our galaxy, and offer new insights on how these giant black holes interact with their sur- roundings.” The EHT team’s results are being published in a special issue of The Astrophysical Journal Letters . Because the black hole is about 27,000 light-years away from Earth, it appears to us to have about the same size in the sky as a doughnut on the Moon. To image it, the team created the powerful EHT, which linked together eight existing radio observatories across the planet to form a single “Earth-sized” virtual telescope. The EHT observed Sgr A* on multiple nights in 2017, collect- ing data for many hours in a row, similar to using a long exposure time on a camera. In addition to other facilities, the EHT network of radio observatories includes the Atacama Large Mil- limeter/submillimeter Array (ALMA) and the Atacama Pathfinder EXper- iment (APEX) in the Atacama Desert in Chile, co-owned and co-operated by ESO on behalf of its member states in Europe. Europe also con- tributes to the EHT observations with other radio observatories — the IRAM 30-meter telescope in Spain and, since 2018, the NOrthern