For the past century, the only evidence astrophysicists have had for the existence of black holes has been scientific theories and indirect observations. The cosmic giants have a gravitational attraction so powerful that nothing can escape their immense pull, and their existence has been incredibly challenging to verify. And yet, in spite of the major difficulties, scientists have managed to generate an image of one.
The picture in question is of the fiery disk of accreted gas surrounding the black hole at the core of the Messier 87 galaxy. With a diameter of 38 billion kilometers (23.6 million mi), the active supermassive colossus lurks 55 million light-years from our planet. The black hole itself is impossible to literally “see,” but the dark area at the center of the ring corresponds to its shadow.
To capture the image, a task described by leading astrophysicist France Cordova as “Herculean,” scientists deployed the Event Horizon Telescope (EHT), a global network of high-precision radio telescopes. This Herculean task required a Herculean amount of data, so much that it was impossible to transfer over the Internet. Instead, half a ton of hard drives had to be flown to a central location, where the readings were combined using state-of-the-art processing techniques.
The image appears to verify the first predictions of black holes made by Einstein’s general theory of relativity, which addresses the distortion of space and time caused by immense, massive objects. The EHT researchers now have their sights on Sagittarius A—the supermassive beast at the heart of the Milky Way.