What’s the loudest sound you can imagine? An airplane? A monster? A rock concert? Sure, those are loud, but don’t hold a candle to the world’s loudest noise.
The truth is, the loudest sound on Earth would probably kill you if you heard it. So, what’s the sound? Well, we don’t really know. Consider this list:
There you have it, the Saturn V Rocket is the loudest sound we can hear. But there may be more to the story. Consider this story from fivethirtyeight:
On the morning of Aug. 27, 1883, ranchers on a sheep camp outside Alice Springs, Australia, heard a sound like two shots from a rifle. At that very moment, the Indonesian volcanic island of Krakatoa was blowing itself to bits 2,233 miles away. Scientists think this is probably the loudest sound humans have ever accurately measured. Not only are there records of people hearing the sound of Krakatoa thousands of miles away, there is also physical evidence that the sound of the volcano’s explosion traveled all the way around the globe multiple times.
Now, nobody heard Krakatoa in England or Toronto. There wasn’t a “boom” audible in St. Petersburg. Instead, what those places recorded were spikes in atmospheric pressure — the very air tensing up and then releasing with a sigh, as the waves of sound from Krakatoa passed through. There are two important lessons about sound in there: One, you don’t have to be able to see the loudest thing in the world in order to hear it. Second, just because you can’t hear a sound doesn’t mean it isn’t there. Sound is powerful and pervasive and it surrounds us all the time, whether we’re aware of it or not.
For instance, the loudest animal on Earth might live in the ocean. Sperm whales use echolocation to navigate, similar to what bats use — they make a clicking sound and can figure out what’s around by the way that sound wave bounces off objects and returns to them. A sperm whale’s click is 200 decibels, the unit used to measure the intensity of a sound, said Jennifer Miksis-Olds, associate professor of acoustics at Penn State. To give you a sense of the scale, the loudest sound NASA has ever recorded was the first stage of the Saturn V rocket, which clocked in at 204 decibels.
So, the loudest sound on Earth is either the Saturn V Rocket or the rumbling of Krakatoa, two events you’re unlikely to hear anytime soon. So, until then, there’s always thunder to keep an ear out for.