Have you ever wondered what that rumbling noise is in your head? If you can hear it - and create it at will - you are an ear rumbler, and one of only a small number of people who can do it.
Every now and then, people on social media "discover" the superpower, though it's actually been known about since 1884, if not before.
People have fallen into categories of people who can do this and were unaware that other people can't, and people who just plain can't do this.
"A part of the human population can voluntarily control the tensor tympani, a muscle within the ear," Massimo wrote on Twitter. "Contracting this muscle produces vibration and sound. The sound is usually described as a rumbling sound."
If you can do it, there's even a subreddit "Ear Rumblers Assemble" where you can go and talk about ear rumbling with other ear rumblers, or share memes about ear rumbling. Go find your ear rumble brothers and sisters.
In that subreddit you will find people talking about how they use their superpower, e.g. to drown out moviegoers giving out spoilers outside a cinema.
If you'd like to find out if you can make this sound, you can try screwing your face up really tightly, including your eyes. Go ahead and try it, don't feel embarassed, I'm sure nobody is watching. Did you hear it? Most people describe it as a rumbling noise, with some describing it like a thunder.
"To me it sounds like when there’s a big thunderstorm," one Twitter commenter wrote. "The thunder is just lowly rolling around in the sky forever with only tiny flashes of lightning that don’t leave the clouds."
So, what is this sound? The tensor tympani is a muscle that dampens out louds sounds, like thunderstorms and the sound of your own chewing. When tensed, the muscle is responsible for tensing the eardrum, which dampens vibrations and reduces the perceived loudness of sound.
Some people are able to contract it voluntarily when there are no loud sounds to dampen out, and contracting muscles produce vibrations and sounds of their own, which is what you're hearing.
If you can't hear it voluntarily, you can simulate the sound by placing a different contracted muscle next to your ear (sorry, you didn't need to scrunch your face up after all, and looked like a weirdo for no reason whatsoever). A clenched fist should do the trick, and will give you the sound that us ear rumblers can do entirely at will. Enjoy your new superpower.
A version of this article was first published in February 2020.