We've all seen the incredible first image of a supermassive black hole, but how on earth do you capture something so far away and that, by its very definition, consumes light?!
The capture is a significant moment for astronomers and astrophysicists. It may not look much, but the complexity of the work that went in to getting any image at all is staggering. In all honesty, everything that is said about the black hole is beyond genuine comprehension. The black hole is in a "nearby" galaxy called M87, which is around 53 million light-years from earth. Despite its relative small size, its density shows a mass of an estimated 6.5 billion suns. Nothing is remotely relatable and one has to just appreciate the news abstractly, however fascinating.
The problems of capturing a black hole are large and plentiful. The distance for one, means the telescope has to focus in on an infinitesimally small part of the night sky, on a subject that for all intents and purposes, is invisible. In fact, as no light can escape or be reflected, there's nothing for any camera sensor — no matter how advanced — to pick up. However, what we can instead capture is the chaos swirling around the center point. In the above image, what we are witnessing is the event horizon (through an international network of radio telescopes called Event Horizon Telescope) as the light crosses over the threshold. The light we see is from the hot gas that gets heated as it crosses over the event horizon and in to the darkness of the black hole.
The science and mathematics that went in to taking this first images is truly staggering. Not only from a photographic stand point either, but from the complicated algorithms and computation necessary to extract any image at all from the data. In this video, Katie Bouman, a PhD student at MIT, discusses what it takes to capture a genuine image of a black hole for the first time. It's also worth noting, she was perfectly accurate with her prediction of when we would get our first image!