In the 1990s, many countries signed an agreement to outlaw tests of nuclear weapons and in order to make sure no one was violating the pact, they set up a system of sensors that pick up the low-frequency waves that nuclear explosions send over long distances. But interestingly enough, because most countries adhere to the agreement, most of what the system picks up isn't actually nuclear tests, but other things that emit low-frequency sounds, such as rocket ship take-offs, volcanic eruptions, ship engines, the vibrations of icebergs, earthquakes, and...you got it, whale songs!
So while this sensor system was put into place for a sort of big-brother effect, it has actually led to a lot of new knowledge regarding the earth and atmosphere. For instance, the sensing of underwater earthquakes allows scientists to better predict and warn about potential tsunami dangers. Scientists can also use the system via whale songs to track whales for research purposes, instead of just wandering through the ocean on a dingy hoping to find a whale and tag it. The system also picks up frequencies from meteoroids that travel through the atmosphere and we have discovered that there are way more meteoroids out there than we previously thought. What else can the sensing system tell us? Watch the video to find out!