In the second half of the 20th century, more than 2000 nuclear test bombs were detonated across the globe. Things slowed down quite a bit in the 1990s: That was when most of the world’s nations signed a treaty agreeing to stop testing of nuclear weapons. That ban did more than limit the bombs’ harmful effects on the environment—since its implementation, it’s made the jobs of some scientists a lot easier.

In their latest video, MinuteEarth explains how the nuclear test monitoring system doubles as a research tool. The system is designed to detect illegal nuclear bomb explosions, but it also picks up other sounds produced at different frequencies. Scientists who borrow this data can learn more about whales, earthquakes, meteors, the atmosphere, and more. Check out some of the exciting discoveries this has led to below.

[h/t MinuteEarth]