Black Hole Sun

How to take a picture of something that’s structurally obsessed with not letting light escape has been the stuff of scientific preoccupation for the last 40 or 50 years or so. The basic idea, just in case you’re not familiar, is that around a black hole there’s something called an Event Horizon, which is the point of no return for light or anything else. In people terms, this is the point where if you were to fall into one all your little bits and crumblies would be collapsed into intergalactic pound cake in a jiffy. I started Netflix’s documentary on the subject last night finally, and while I watched I decided to do some sketching on my iPad. It’s helpful for me to have something to do while I’m learning something new, and drawing pixel art seems to be particularly constructive for me for one reason or another so off I went.

One topic that comes up during the first part of it is the black hole information paradox, first identified by Stephen Hawking back in the 70s. It wrestled with an apparent lack of unity between the theory of general relativity and quantum mechanics, as it appeared that black holes were giving off a type of radiation (all types of which contains quantum information) but that our current understanding of them implied that information would be completely scrambled and upon the death of a black hole completely lost. Here’s what that means, with the understanding that these are very broad brush strokes.

If a black hole is giving off radiation, then the reasonable conclusion is that it will run out of mass at some point and cease to exist. Since two of quantum mechanics’ big ideas are quantum determinism (the future state of any system can be determined by understanding its present state on a microscopic level via the evolution operator in Schrödinger’s equation) and the principle of reversibility (basically, the inverse of the evolution operator used for quantum determinism), we should be able to study the black hole radiation and know what it was created by/from/etc because the system’s information is never lost.

The paradox here is Hawking’s work concluded that the radiated information left at the death of a black hole would be scrambled or devoid of anything related to what had caused or fallen into the black hole, meaning that black holes were the only things in the universe that could destroy information. Just like matter is neither created nor destroyed, just reorganized I suppose you could say, quantum information is supposed to be the same, and finding a case where that isn’t true was startling and in many ways horrifying. The implication being that if you fell into a black hole, scientists in the future who studied it would perhaps not only not know you ever fell into it or ever existed, but might be getting the indication that a trombone had fallen into it instead. Since archeology has largely been the study of ancient trash, and black holes are perhaps the ultimate trash compactor, stuff like this meant that not only would studying black holes not really give us an accurate understanding of their surrounding galactic countryside, it also meant that maybe we were wrong about everything.

It’s not all doom and gloom though folks, scientists have made a lot of progress on sorting this paradox out and if you want to read a bit of an update on it you can check that out here. They also managed to take a picture of the black hole, which you probably saw all over the internet sometime in the last few years or at least found at the top of this email. Truly incredible stuff, and helpful (at least for me) to put my day to day difficulties in better perspective. Happy Wednesday.