NASA’s Curiosity Mars rover captured these “sunbeams” shining through the clouds at sunset on February 2, 2023, at 3,730. Mars day, or Sun, for the mission. It was the first time that solar rays, also known as crepuscular rays, have been seen so clearly on Mars. Credit: NASA/JPL-Caltech/MSSS
The veteran Martian rover captured a dazzling sunset at the start of a new cloud imaging campaign.
Although Martian sunsets are uniquely moody, NASA‘s Curiosity rover captured one last month that really stands out. As the Sun set over the horizon on February 2, rays of light illuminated a bank of clouds. These “sunrays,” also known as crepuscular rays, from the Latin word for “twilight,” are streaks of light that occur when incoming light is partially blocked by a cloud or high feature on the horizon. It was the first time that the sun’s rays were clearly seen Mars.
Curiosity captured the scene during the rover’s latest twilight cloud survey, which builds on its 2021 observations of nocturnal or nocturnal clouds. While most Martian clouds do not hover more than 60 kilometers above the ground and are composed of water ice, the clouds in the latest images appear to be at a higher altitude, where it is particularly cold. This suggests that these clouds are made of carbon dioxide ice or dry ice.
As on Earth, clouds provide scientists with complex but crucial information for understanding the weather. By looking at when and where clouds form, scientists can learn more about the composition and temperatures of the Martian atmosphere and its winds.
This feathery iridescent cloud was captured just after sunset on January 27, 2023, 3724. Mars day, or sun, for Curiosity’s mission. Studying the colors in iridescent clouds tells scientists something about the particle size in the clouds and how they grow over time. Credit: NASA/JPL-Caltech/MSSS
The 2021 cloud survey included more imaging from Curiosity’s black-and-white navigation cameras, providing a detailed look at a cloud’s structure as it moves. But the recent study, which began in January and will conclude in mid-March, relies more often on the rover’s color Mast Camera, or Mastcam, which helps scientists see how cloud particles grow over time.
In addition to the image of sun rays, Curiosity captured a set of colorful clouds shaped like a feather on January 27. When illuminated by sunlight, certain types of clouds can create a rainbow-like display called iridescence.
“Where we see iridescence, it means that a cloud’s particle sizes are identical to their neighbors in every part of the cloud,” said Mark Lemmon, an atmospheric scientist at the Space Science Institute in Boulder, Colorado. “By looking at color transitions, we see the particle size change across the cloud. This tells us about the way the cloud evolves and how its particles change size over time.”
Curiosity captured both the sun’s rays and iridescent clouds as panoramas, each pieced together from 28 images sent to Earth. The images have been processed to emphasize the highlights.
More about the mission
Curiosity was built by NASA’s Jet Propulsion Laboratory, which is managed by the California Institute of Technology (Caltech) in Pasadena, California. JPL manages the mission on behalf of NASA’s Science Mission Directorate in Washington. Malin Space Science Systems in San Diego built and operates the Mastcam. Curiosity’s Mastcam consists of two camera systems mounted on the rover’s mast, which allow for panoramic and stereoscopic imaging of the Martian surface. The Mastcam system was designed to support the mission’s science objectives, including the search for evidence of past or present habitable environments on Mars, and the study of Martian geology and climate. Mastcam has been used to capture some of the most iconic and detailed images of Mars ever taken, including images of the planet’s diverse terrain, geological features and atmospheric phenomena.