Hey, it’s a relevant question — particularly since astronomers at the Chandra X-ray Observatory have found that the Perseus galaxy is emitting a B-flat drone. Mind you, it’s 57 times lower than the lowest note on a piano, so unless you have subwoofer in your stereo that’s oh, about four million feet tall, you’re unlikely to hear this particular note sampled in the latest electroclash compliation.

And hey? What does the Perseus nebulae care about musical trends? It’s been humming that note for 2.5 million years — the longest-running celestial Top-40 hit, as it were. If you want the details on how they managed to hear this tone, check out the story at Space.com:

The Perseus cluster is the brightest known in X-rays, making it a good target for study. It has two large, bubble-shaped cavities that extend away from a central black hole. The cavities are formed by jets of material ejected from the black hole’s surroundings, and the jets have been suspected of heating the outlying gas. But scientists couldn’t see how.

A special image-processing technique was used to bring out subtle changes in brightness that revealed the presence of ripples — the sound waves.

Fabian and Allen figure the sound waves, observed spreading out from the cavities, heat the gas. The amount of energy involved is staggering, equal to what would be produced if 100 million stars exploded.