Known as the Event Horizon Telescope, named after the point of no return in a black hole, its job was to see what has been until now unseeable: an exquisitely small, dark circle of nothing, a tiny shadow in the glow of radiation at the center of the Milky Way galaxy. Top right: While the EHT can zoom in very close to the event horizon, down to scales of only 0.01 light years (or 3.7 light days), i.e., a region comparable to the size of our Solar System, the relativistic jet (extended across several thousand light-years) can be probed using ALMA intra-baselines, recorded during the EHT observations (greyscale image).PICO DE ORIZABA NATIONAL PARK, Mexico - Sheperd Doeleman’s project to take the first-ever picture of a black hole wasn’t going well.įor one thing, his telescope kept filling with snow.įor two weeks at the end of March, Volcan Sierra Negra, an extinct 15,000-foot volcano also known as Tliltepetl that looms over the landscape in southern Mexico, was the nerve center for the largest telescope ever conceived, a network of antennas that reaches from Spain to Hawaii to Chile.
The emission between the photon ring and the event horizon is due to emitting plasma either in the accretion flow and/or at the footprint of the jet (this emission is generally too dim to be detected by the EHT). Gravitational lensing magnifies the apparent size of the black hole’s event horizon into a larger dark shadow.
The north–south asymmetry in the emission ring is produced by relativistic beaming and Doppler boosting (matter in the bottom part of the image is moving toward the observer) and is mediated by the black hole spin (which is pointing away from Earth and rotating clockwise). Left: The black hole feeds on a swirling disc of glowing plasma, driving a powerful relativistic jet across several thousands of light years.īottom right: Approaching the black hole, gravity is so strong that light is severely bent, creating a bright (almost circular) ring.