Looks like the worldwide hum has a companion:
Mysterious whistle-like noise from Caribbean Sea is so powerful that it can be heard from space.
The sound, a whistle, is so powerful its vibrations can be picked up from space. By machines. Humans can’t hear it because the sound, at “nearly ’30 octaves below the bottom of a piano,” is beyond human hearing range.
July 5, 2016 Acoustics, Everyday noise, Mystery noise 0 Read more >