Watch these rare blue clouds ripple across the sky

At this point, we're pretty used to NASA bringing us all sorts of interstellar fascination. We posted about some just this Monday, in fact.

But for all of the marvels that exist throughout our solar system and beyond, it's worth remembering that Earth is still full of mysterious beauty. Case in point, this video!

Electric blue

This image really helps you see how high in the atmosphere PMCs are. (NASA)

Thanks to a giant weather balloon that traveled from Sweden to Canada this July, NASA was able to capture multiple images of Polar Mesospheric Clouds, or PMC. These ultra-high, ultra-cold clouds are only visible at twilight. They are made of ice crystals and radiate a mesmerizing blue and white in the sky. Even more amazing, you can see ripples in the atmosphere called gravity waves as they travel across them.

We think these rare blue clouds are just about the coolest we've ever seen. Do you agree? Watch and decide for yourself!