Photo credit: explorersweb.com
For the fourth consecutive year, NASA’s Curiosity rover has captured stunning images of iridescent clouds floating in the Martian atmosphere. These clouds have been recorded at the same location and time each year, showcasing a remarkable pattern.
On January 17, during Mars’ early autumn, Curiosity’s Mastcam documented these noctilucent clouds for 16 minutes. The sunlight scatters against these formations, resulting in vibrant, pearlescent clouds that exhibit hues of red and green.
Cloudgazing… on Mars!
@MarsCuriosity captured these colorful clouds drifting across the Martian sky. The iridescent, carbon dioxide ice formations offer clues about Mars’ atmosphere and weather: https://t.co/HAp2FDFjhk pic.twitter.com/DEWV477X01
— NASA (@NASA) February 11, 2025
Characteristics of Dry Ice Clouds
While typical Martian clouds are primarily comprised of water ice, the noctilucent clouds are believed to be formed from frozen carbon dioxide, also known as dry ice. These clouds exist at altitudes ranging from 60 to 80 kilometers above Mars, where extreme cold causes carbon dioxide to condense into these delicate, vivid formations. Some of the plumes may drop to 50 kilometers elevation before vaporizing due to increasing temperatures.
Twilight clouds on Mars were initially observed during NASA’s Pathfinder mission back in 1997. The recent sightings by Curiosity mark the fourth appearance of these iridescent clouds over Gale Crater in the southern hemisphere of the planet, consistently appearing at the same seasonal time each year.
This regularity has enabled scientists to schedule their studies of the Martian atmosphere more effectively. Mark Lemmon, an atmospheric expert at the Space Science Institute, reflects on his first impressions of the clouds: “Initially, I thought it might be some color artifact… Now, it’s become so predictable that we can plan our observations ahead of time.”
Interestingly, these twilight clouds do not seem to manifest elsewhere on Mars. One possible explanation is that atmospheric gravity waves generate conditions conducive to cloud formation by cooling the surrounding atmosphere.
However, this remains a hypothesis. “The dynamics of Martian gravity waves are still not completely understood, and it is unclear why these twilight clouds form in a specific region but not in others,” says Lemmon.
Source
explorersweb.com