Recently captured images from NASA’s Curiosity rover reveal vibrant clouds drifting in the Martian sky.
The rover’s Mastcam captured these stunning images, which NASA’s Jet Propulsion Laboratory likens to the rover’s own vision. The clouds were observed on January 17, and the photographs were taken over a span of 16 minutes, as stated in a news release from the space agency.
These clouds, referred to as noctilucent or twilight clouds, consist of frozen carbon dioxide, commonly known as dry ice. Their colors are highlighted by the light scattering from the setting Sun, leading to their nickname, “mother-of-pearl” clouds.
Although Mars’ atmosphere is predominantly carbon dioxide—around 95%—few clouds exist at the altitudes and cool temperatures necessary for frozen carbon dioxide to form. The majority of Martian clouds are composed of water ice. The clouds documented by Curiosity hover at heights of 37 to 50 miles above the surface. Additional images depict these clouds as white wisps descending through the atmosphere, dissipating roughly 31 miles above Mars.
NASA/JPL-Caltech/MSSS/SSI
The twilight clouds have only been observed in select regions of Mars’ southern hemisphere. NASA’s Perseverance Rover, which landed in the northern hemisphere of Mars in 2021, has yet to observe these clouds since its arrival, while Curiosity has detected them multiple times across four Martian years in the southern hemisphere.
Mark Lemmon, an atmospheric scientist at the Space Science Institute in Boulder, Colorado, expressed to NASA that certain areas on Mars may have a higher likelihood of producing these clouds. He suggested that gravity waves, which have a cooling effect on a planet’s atmosphere, could play a role in their formation.
“The condensation of carbon dioxide into ice was not initially anticipated here, indicating that some cooling process is taking place,” Lemmon noted in NASA’s news release. “However, the workings of Martian gravity waves remain somewhat elusive, leaving us uncertain as to why twilight clouds form in specific locations.”
Despite the limited understanding of cloud formation, researchers can successfully predict their emergence. Lemmon, who co-authored a 2024 paper detailing Curiosity’s initial two years of cloud observations, mentioned that the phenomenon has “become so predictable that we can plan our imaging sessions in advance.”
The latest photos of clouds aren’t the only findings Curiosity has relayed to NASA in recent weeks. The rover has also examined a region called the Gediz Vallis channel, according to the space agency.
Additionally, Curiosity explored an impact crater nicknamed “Rustic Canyon,” capturing images and studying the surrounding rocks. This 67-foot-wide crater is believed to have formed millions of years ago due to erosion, as reported by NASA.
The rover will proceed to a new destination featuring what NASA describes as “boxwork,” or fractures in the Martian surface created by groundwater erosion. Viewed from space, these fractures resemble vast spiderwebs, according to NASA.
