Geek Trivia: Low and behold

What celestial object emits the lowest frequency note ever detected, far below the low-frequency hum produced by Earth?

A black hole at the center of a galaxy in the Perseus Cluster is currently generating a deep B-flat note that's 57 octaves below a tuned middle C on a piano.

Put another way, the lowest frequency sound a human being can detect is 0.05 hertz, or a frequency of one-twentieth of a second. The Perseus Cluster black hole generates sound with a frequency of 10 million years. This represents the most sub-bass frequency ever detected.

To be precise, the black hole itself is silent, but the stellar gases pulled into the gravitational well of the black hole are not. As the gas falls toward the black hole's event horizon, it accelerates to velocities approaching the speed of light. This acceleration creates turbulence, which in turn generates light, heat, and, within the medium of the gas, sound.

Of course, space being a near total vacuum (and the black hole being 250 million light years away), the sound of the black hole hasn't actually reached Earth. British astronomers discovered it using NASA's Chandra X-ray Observatory while trying to analyze the formation of galactic clusters such as Perseus.

The black hole in question is unusually energetic, emitting a significant amount of X-ray radiation, which scientists used to model the thermal and kinetic activity of the matter pulled into the black hole.

This modeling revealed the sonic tone induced by the black hole, which could help explain why galactic gas clusters stay warm, rather than cooling and collapsing. Massive celestial objects such as black holes are "ringing" the gas clusters, which keep them energized and hot, leading to some of the specific star formation behavior that scientists had previously been unable to explain. Now that sounds like some great Geek Trivia.