Now, for the first time, a group of radio antennas knows as the Event Horizon Telescope Collaboration have unveiled the first image of the supermassive black hole four million times more massive than our Sun.
known as Sagittarius A* (Sgr A*, pronounced "sadge-ay-star") it obviously can't be seen, that is built into the black hole name, but it can be inferred thanks to a dark central region (called a “shadow”) surrounded by a bright ring-like structure. The new view captures light bent by the powerful gravity of the black hole.
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 donut on the Moon. To image it, eight existing radio observatories across the planet, the Atacama Large Millimeter/submillimeter Array (ALMA), the Atacama Pathfinder Experiment (APEX), the IRAM 30-meter Telescope, the James Clerk Maxwell Telescope (JCMT), the Large Millimeter Telescope Alfonso Serrano (LMT), the Submillimeter Array (SMA), the UArizona Submillimeter Telescope (SMT), the South Pole Telescope (SPT), formed a single “Earth-sized” virtual telescope.
Using The EHT observed Sgr A* on multiple nights, collecting data similar to using a long exposure time on a camera.
Credit: EHT Collaboration
The EHT has made a lot of progress in a short amount of time. It was just three years ago they created the first image of a black hole, called M87, at the center of the more distant Messier 87 galaxy.