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This, Amory, is one of my favorite summer jams of all time because it's hot. They am hot.

They am hot. You got that right. Today for our series of best hot off the grill, fresh slice of watermelon, what have you and list thread episodes for the month of July.

A story produced with lots of help from Dean Russell, Kraken towel. Unleash the Kraken towel.

This is a story about a sound. We can't hear it. Really. Because the instruments that recorded it when it happened in 1883 were rudimentary.

But they still registered it because it was so massive, so complete, it changed the atmosphere across the planet.

The effects that were measured the farthest have to do with airwaves.

Since then, scientists around the planet have tried to recreate it from the original instrument readings.

It was recorded by every working barro graph on the planet and some of them recorded the airwaves circling the earth seven different times.

The atmospheric shockwave recorded by these barro graphs lasted for five days. If you spread the recording up, it might have sounded like this.

But when it happened, it was lower, deeper.

The dominant sound drops in pitch below what we consider to be audible sound.

Humans can generally hear a spectrum that starts around 20,000 hertz, which sounds like this.

For many, this frequency may be inaudible. Here's 15,000.

10. 5,000 hertz. Here's 1,000.

500. Here's 60 hertz.

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