This Is Why The Event Horizon Telescope Still Doesn’t Have An Image Of A Black Hole
Across multiple continents, including Antarctica, an array of radio telescopes observe the galactic center.
This network, the Event Horizon Telescope (EHT), is imaging, for the first time, a black hole’s event horizon. Of all the black holes visible from Earth, the largest is at the galactic center: 37 μas. With a theoretical resolution of 15 μas, the EHT should resolve it.
Despite the incredible news that they’ve detected the black hole’s structure at the galactic center, however, there’s still no direct image. They found evidence for an asymmetric source, about 3 Schwarzschild radii large: consistent with Einstein’s prediction of 2.5.
But before the South Pole data, delivered five months ago, can be added, all error sources must be identified. Earth’s atmospheric turbulence, instrumentation noise, and spurious signals require identification, obtainable through additional imaging. Although the data has been combined, novel algorithms must be developed to process them into an image. Only two black holes, Sagittarius A* and M87, could have event horizon “silhouettes” imaged.