The Overthinkers began with a late-night

discussion of a distant galaxy.

Perseus Cluster, image credit: NASA, 2017

 Ian and Mike met at the birthday party of a mutual friend’s dog. (This was no ordinary dog - she was a kind and inquisitive soul who liked to lay on the floor with her front paws crossed, in a gesture of delicate elegance. She was loved by all who met her and her birthday was reason enough to draw dozens of friends together from all walks of life.) On this particular night, amid the patter and general noise of revelry, Mike and Ian were introduced by Dominique (Ian's badass then-fiancé, now wife!) and soon found themselves deep in a conversation about black holes.


In a serendipitous coincidence, they had both seen the same article recently - a paper published by a team from England who analyzed the results of a long exposure of the Perseus galaxy cluster by an orbiting X-ray telescope known as the Chandra X-ray Observatory. The Perseus galaxy cluster is 250 million light years away - meaning the light that left that cluster was emitted before dinosaurs even existed on earth. And when the astronomers analyzed the light that left that cluster, they found something strange: music. Or more accurately, a single note.


Turns out, there was a black hole in that galaxy cluster, one that was voraciously feeding on galactic gas and dust. As it fed, the matter formed into super-fast jets at the poles. As those jets of matter spewed outwards, they swung around in a long slow arc, following the spinning of the black hole itself. When the jets encountered other gas clouds in the surrounding space, they slammed into them, creating a pressure wave.


These pressure waves propagated outwards at a particular frequency, in just the same way that a piano key, when pressed, creates pressure waves that propagate outwards. In the case of, say, the piano note middle C, the pressure waves spread outwards at a rate of 262 waves per second. It’s easy enough to determine the note of any regular sound if you know the frequency. The team of astronomers analyzed the frequency of the pressure waves generated by the black hole in the Perseus galaxy cluster so many millions of light years away and they came up with a result.


The Perseus black hole was singing a B♭. The B♭in question is 57 octaves below middle C on a piano keyboard - that’s a million billion times lower than the lowest sound audible by the human ear - but it’s a B♭nonetheless.


The first time they got together to make music together, which ended up being the first of countless times and the beginning of a true musical partnership, they jammed in the key of the Perseus black hole.