> The early clouds are at higher altitudes than most Martian clouds— which typically hover about 37 miles above the planet’s surface and are made up of water ic

> The early clouds are at higher altitudes than most Martian clouds— which typically hover about 37 miles above the planet’s surface and are made up of water ice. The higher-altitude clouds are likely made of frozen carbon dioxide, or dry ice, NASA says. "Very cool" indeed.