Last Tuesday, the weather at the Event Horizon Telescope (EHT) command center in Cambridge, Massachusetts couldn’t have been much worse: it was rainy and barely 40 degrees F. But that wasn’t important. What mattered were the conditions in Hawaii, Arizona, Spain, central Mexico, northern Chile, and at the South Pole. Was the weather good in all those places simultaneously? If so, they had a shot at imaging a black hole.
For this experiment, some 50 astronomers from around the world had traveled to high-frequency radio telescopes on four continents: ALMA and the Atacama Pathfinder Experiment in Chile; the Large Millimeter Telescope in Mexico; the Submillimeter Telescope in Arizona; the Submillimeter Array and the James Clerk Maxwell Telescope in Hawaii; the IRAM 30-meter telescope on Pico Veleta in Spain. A crew wintering over in Antarctica, whom EHT astronomers trained months earlier, would operate the South Pole Telescope. Using a technique called Very Long Baseline Interferometry, the astronomers would unite these geographically distant stations into a virtual Earth-size telescope capable of imaging the “shadow” that certain supermassive black holes cast against the glow of surrounding, superheated matter. A prime target is Sagittarius A*, the 4 million-solar-mass giant at the center of the Milky Way.
To read more, click here.