A Martian rover has recorded breathtaking visuals of peculiar extraterrestrial clouds glistening with rainbow colors as they float across the Red Planet’s atmosphere.

NASA’s Curiosity rover, acting as the agency’s robotic eyes on Mars, documented 16 minutes of *noctilucent clouds*—commonly referred to as twilight clouds—on January 17. These fragile formations are too faint to be perceived in daylight but turn iridescent as they disperse light from the setting sun.

Researchers have released a time-lapse video of the spectacle, showcasing the captivating red and green shades of the clouds.

While analogous high-altitude clouds are present on Earth, significant distinctions exist between those on Mars and those on our planet. Earth’s noctilucent clouds are made up of water ice, in contrast to Mars’ variant, which is formed from dry ice (frozen carbon dioxide), a variety of cloud that does not occur in Earth’s atmosphere. Mark Lemmon, an atmospheric scientist at the Space Science Institute in Colorado, asserts that Mars lacks the necessary water vapor at elevated altitudes to produce water-ice clouds capable of reflecting sunlight after dusk.

“I believe Earth has prettier noctilucent clouds more frequently, depending on where you live,” Lemmon stated to *Mashable*. “The best from either planet is quite stunning.”

### A Celestial Perspective from Mars

In the video, the noctilucent clouds are visible near the frame’s upper edge, hovering at elevations between 37 and 50 miles. These visuals were obtained using Curiosity’s left Mastcam as the rover progresses toward the *boxwork region* surrounding Mount Sharp.

Although the footage might appear to be a view from space, as if gazing at the curved perimeter of Mars, it is indeed a ground-level observation. The absent corners in the images create the illusion of a planetary dome, but they stem from a jammed color filter wheel on the rover’s camera.

### The Enigma of Noctilucent Clouds

Since at least the 19th century, astronomers have documented Earth’s noctilucent clouds, which emerge at extreme altitudes—around 50 miles above the surface in the mesosphere. Unlike standard rain clouds, which form no higher than 10 miles up, these glimmering clouds consist of water-ice crystals.

Scientists were predominantly in the dark regarding their origin until NASA’s *Aeronomy of Ice in the Mesosphere* (AIM) initiative commenced its studies roughly 20 years ago. Researchers discovered that these clouds develop when ice crystals condense around minuscule particles of meteor smoke—remnants of shooting stars that disintegrate in the atmosphere. Unexpectedly, the ice in the mesosphere creates a continuous layer.

During the summer months, these iridescent clouds become visible at dusk and dawn near Earth’s poles. NASA astronaut Matthew Dominick recently captured a stunning image of them from the International Space Station on July 4, 2024.

“We have experienced numerous fantastic sunrises lately with remarkable noctilucent clouds,” Dominick posted on X. “I’ve probably taken about a thousand images of them in the past week.”

### Noctilucent Clouds on Mars

Mars’ iridescent clouds were initially detected in 1997 by NASA’s *Pathfinder* mission. However, Curiosity did not capture them until 2019—over two decades later. This marks the fourth consecutive year the rover has detected these mother-of-pearl carbon dioxide clouds in early autumn.

A lingering mystery persists: Why haven’t these clouds been seen in other locations on Mars? NASA’s *Perseverance* rover, stationed in Jezero Crater in the northern hemisphere, has yet to observe them.

Scientists hypothesize that certain areas of Mars may be more conducive to their formation. One theory proposes that gravity waves—atmospheric disturbances capable of cooling the air—might be causing carbon dioxide to freeze into ice at high altitudes in the southern regions.

Lemmon conducted a study on Curiosity’s initial two seasons of twilight cloud observations, published in *Geophysical Research Letters* late last year. He recalls that when he first encountered the iridescent clouds, he assumed they were an error—perhaps an artifact in the images. Now, scientists are able to predict and prepare for their emergence.

“Their beauty astonishes me every time I witness a new instance,” Lemmon remarked.