The weather on Mars is of great interest to astronauts who may one day venture there and recently the Mars Curiosity rover captured rare and beautiful noctilucent clouds above the Red Planet.
Curiosity’s Mastcam instrument captured night-shining clouds for 16 minutes on January 17 and the footage has perplexed scientists who don’t understand why the clouds only seem to appear in one location in Mars’s atmosphere at the same time each year.
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
In the footage above, which is sped up 480 times, noctilucent clouds can be seen tinged with red and green, the color is created by scattering light from the setting Sun. The rare clouds travel in one direction as lower altitude clouds move in another.
The BBC Sky at Night Magazine explains that noctilucent clouds on Mars are thought to be made up of water ice and carbon dioxide ice — Mars’s atmosphere is over 95 percent carbon dioxide. The clouds appear at an altitude of 37 to 50 miles (60 to 80 kilometers) and were first spotted by NASA’s Pathfinder mission in 1997. They are too faint to be seen in daylight and only become visible when the clouds are especially high and night is drawing in.
It is the fourth time Curiosity has recorded noctilucent clouds, always in the early fall of the Martian year and in the southern hemisphere. Scientists are stumped as to why the twilight clouds haven’t been spotted in other locations. The Perseverance Rover, which is in the northern hemisphere’s Jezero Crater, hasn’t spotted any of the iridescent clouds.
“I’ll always remember the first time I saw those iridescent clouds and was sure at first it was some color artifact,” says Mark Lemmon, an atmospheric scientist with the Space Science Institute in Boulder, Colorado. “Now it’s become so predictable that we can plan our shots in advance; the clouds show up at exactly the same time of year.”
One theory is gravity waves that are cooling the atmosphere.
“Carbon dioxide was not expected to be condensing into ice here, so something is cooling it to the point that it could happen,” adds Lemmon. “But Martian gravity waves are not fully understood and we’re not entirely sure what is causing twilight clouds to form in one place but not another.”
