NASA recently released mesmerizing footage of clouds moving across the Martian sky. The images which compose the 8-frame movies were taken from the Curiosity rover's navigation camera on December 12, 2021. Scientists think the clouds are composed of carbon dioxide ice because of how high they are in the atmosphere — nearly 50 miles above the surface. Since Martian clouds are difficult to see, multiple images were taken of a static background and then subtracted from each image. This technique allowed anything that was moving, such as clouds or shadows, to become visible.