https://www.wired.com/story/the-perplexing-physics-of-imaging-a-black-hole/

It's a big day for astronomy (and all humans, really). The first image of a black hole has been released. It was created using the Event Horizon Telescope—a collaboration of radio telescopes around the world. This image shows the material around a super massive black hole in the center of a galaxy some 55 million light-years away.

Yes, there is a ton of cool physics here, involving the crazy gravitational things that happen in extreme cases like a black hole. But that's not what I want to look at. Instead, I want to go over some of the more basic physics questions related to this image.