NASA’s Curiosity rover captured last month eerie images of clouds passing over the Martian sky. The robot’s NavCam took eight pictures of the sky and another eight of the southern horizon. The Jet Propulsion Laboratory from NASA posted the pictures with the note that the clouds are the clearest we’ve seen so far.
These Rare Clouds Tell Us of Mars’ Past
The statement released by JPL notes that the pictures were taken approximately five degrees to the south of the Martian equator. Charissa Campbell, a member of the Curiosity science team, enhanced the pictures and set them frame by frame to see the changes in the movement of the clouds. John Moores, another team member suggested that the clouds on Mars are made of crystals of ice that are crushed into dust by the cold atmosphere. He added:
The wisps are created as those crystals fall and evaporate in patterns known as ‘fall streaks’ or ‘mare’s tails.’ While the rover does not have a way to ascertain the altitude of these clouds, on Earth such clouds form at high altitude.
These clouds on Mars are indicative of the climate from billions of years ago. Scientists note that this phenomenon is very rare on the Red Planet today. However, scientists suggest that billions of years ago the climate on Mars was warm enough to permit a significant amount of liquid to flow on the surface. The process would go on for extended periods of time. Researchers from the Carl Sagan Institute released a study last year in which they proposed that these clouds could have provided the insulation necessary so that liquid water could flow on the surface of Mars nearly 3 billion years ago.
These clouds may have been a usual sight for the Martian environment, however, today Mars is a cold desert.