Okay, this one is really nerdy…
I read today about the lowest frequency “sound” ever measured, being made by the oscillations of a black hole in the Perseus galaxy cluster. The sound waves (if they can truly be called sound at all) travel through the gas and plasma that surrounds the black hole.
Sound is traditionally measured in hertz, which is cycles per second. The limit for human hearing is 20,000 cycles on the high end, and 20 cycles on the low end. For reference, the big booming bass you hear coming from that way-too-loud car stereo next to you is generally in the 50-60 hertz range.
The sound coming from this black hole, however, is one cycle every 10,000,000 years. Frequency-wise, it’s a B-flat 57 octaves below the middle B on a piano. The human race has not even existed long enough to “hear” a single cycle of this tone.
That’s just too cool.
And oh-so nerdy. (You were warned up front. *laugh*)