Science

The black hole photo explained

“You’re basically looking at a supermassive black hole that’s almost the size of our solar system,” or 38 billion kilometers in diameter, said Sera Markoff, an astrophysicist at the University of Amsterdam.

The image was produced by capturing a form of radiation — high-frequency radio waves — that can pass through galactic gas and dust and the Earth’s atmosphere. The image was captured by the Event Horizon Telescope, a network of radio telescopes across the planet that functioned like a single instrument.

The central dark area surrounds the event horizon — the point of no return, inside of which is the “black” part of the black hole. As pictured, the dark space is about 2.5 times greater in diameter than the event horizon.

According to Einstein’s 1915 general theory of relativity, a black hole contains a singularity, a point of infinite density, where the known laws of physics break down. Anything crossing the event horizon toward the center of the black hole will be torn apart. Even light cannot escape.

The glowing doughnut-like ring shows radiation, in the form of high-frequency radio waves, emanating from superheated material outside the black hole’s event horizon. The asymmetry of bright and dark sections of the ring are caused by the Doppler effect as the matter is coming toward Earth (brighter) or receding (dimmer). The colors are chosen to accentuate differences in the ring.

The ring and the central shadow were anticipated by Einstein’s general theory of relativity, but had not been seen until now. Scientists hope to someday develop a quantum theory of gravity that would help explain the extreme conditions within a black hole.