Opportunity turned its rover eyes skyward to observe clouds drifting overhead that look like cirrus clouds on Earth – featherlike formations composed mostly of ice crystals.
By looking at the clouds, Opportunity learns about seasonal and daily weather patterns on Mars. Scientists want to understand how water vapor is transported around the planet. For example, on the extremely cold red planet, surface ice warmed by sunlight can briefly turn to vapor that rises into the atmosphere and then quickly cools to form ice crystals again, either in clouds or back on the ground. Scientists also estimate wind speed and direction based on the movement of the clouds. It definitely gives you the sense of what it might feel like to sit back and watch clouds on Mars.