Curiosity captured both the sun’s rays and iridescent clouds as panoramas, each of which was composited from 28 images sent back to Earth.
NASA ‘s Curiosity rover on Mars captured on February 2, 2023 how rays of sunlight illuminated a cloud bank as the ‘king star’ set over the horizon.
These ‘sunrays’ are also known as crepuscular rays. It was the first time that the sun’s rays were seen so clearly on Mars .
Curiosity captured the scene during the rover’s latest twilight cloud survey, which builds on its 2021 observations of noctilucent, or night-glow, clouds. While most Martian clouds sit no more than 60 kilometers above the ground and are made up of water ice, the clouds in the latest images appear to be at higher altitudes, where it is especially cold. That suggests these clouds are made of carbon dioxide ice, or dry ice.
Watching the first rays of the sun
Just like on Earth, clouds provide scientists with complex but crucial information for understanding climate. By observing when and where clouds form, scientists can learn more about the composition and temperatures of the Martian atmosphere, as well as the winds that blow within it.
The 2021 cloud survey included more images taken by Curiosity ‘s black-and-white navigation cameras , which provided a detailed view of a cloud’s structure as it moved. But the recent study, which began in January and will end in mid-March, relies more on the rover’s Mastcam color camera, which helps scientists see how cloud particles grow over time.
In addition to the image of the sun’s rays, Curiosity captured a set of colored feather-shaped clouds on January 27. When illuminated by sunlight, certain types of clouds can create a rainbow-like spectacle called iridescence.
“When we see iridescence, it means that the particle size of a cloud is identical to that of its neighbors in every part of the cloud,” said Mark Lemmon, an atmospheric scientist at the Boulder Institute for Space Sciences in Colorado. “By looking at the color transitions, we see that the size of the particles is changing throughout the cloud. That tells us about the way the cloud is evolving and how its particles are changing size over time.”
Curiosity captured both the sun’s rays and iridescent clouds as panoramas, each of which was composited from 28 images sent back to Earth. The images have been processed to bring out the highlights.