Have you ever wondered what ice sounds like? Apparently, it sounds like a ray gun from an old school sci-fi movie.
Mathematician and author Mårten Ajne likes to challenge himself by doing Swedish “wild skating.” To do it, a skater seeks out the thinnest, most pristine black ice possible — which is why it emits those weird, laser-like sounds as they pass by. It’s actually the sound of the ice cracking as the waves ripple through the water.
Wild skating is especially dangerous, since the ice can be as thin as two inches. Naturally, this means there’s a very considerable risk of falling through it. Most wild skaters go in groups. Ajne, of course, took his friend and filmmaker Henrik Trygg along to capture it all on video.
In order to determine whether the black ice can bear a skater’s weight, Ajne measures the temperature, atmospheric conditions, and the smoothness of the surface. It also takes a lot of experience.
Around the 1:44 mark in the video, you can actually see the ice moving along the surface of the water, just in case you’re not convinced of how thin it is.
For someone like Ajne, this type of skating must be an otherworldly experience — but don't try it at home, kids.