Earlier this month, an image of what could easily be mistaken as an out-of-focus picture of a Krispy Kreme donut in a dark room became the talk of the town. Headlines above this picture read “First Ever Picture of a Black Hole,” or something like that. My interest was piqued. However, I never actually read past the sensational headlines until it came up in conversation, and I realized had zero knowledge of the story (besides the fact that a black hole can look delicious). So, I did my homework and discovered that the process involved in creating the image and the relevance of it, was quite interesting.
Black holes are possibly the most extreme events in the universe. They are infinitely dense, infinitesimally small objects that exert such an extreme gravitational force upon their surroundings that not even light can escape. This creates a point in spacetime that is inaccessible to the rest of the universe. And so, gathering any information about black holes is very tricky. The fact that we have gathered enough information to know they are even out there is a big deal. This picture is significant because it helps confirm a lot of what we know is accurate.
Something important to note is that this is not an optical picture. It was not taken by an optical telescope like the Hubble. It is an image created using data collected over the course of about a week from 8 radio telescopes around the world that was then processed by a couple of supercomputers using a specially designed algorithm. Together, the telescopes produced 5 petabytes of data while trained on the center of M87 (the galaxy in which the black hole is located). The resulting image is a representation of radio waves emitted by gas swirling around the black hole. The spherical event horizon imposes its dark dominion in the center of the image. Hence, the donut shape.
If you look at this image and are not impressed, then consider what was accomplished. Hundreds of scientists over the course of years worked together to develop specialized algorithms, then coordinated the simultaneous operation of 8 telescopes around the world to create one giant telescope so they could take a picture of something that, by definition, cannot be seen. For a great explanation of how it worked check out this MIT grad student’s TED talk.