NASA’s Curiosity rover has once again captured a stunning scene on Mars, this time featuring the planet’s uniquely moody sunset. On February 2nd, 2023, as the Sun descended over the Martian horizon, rays of light illuminated a bank of clouds in what is being referred to as the first time sun rays have been so clearly viewed on the red planet. These rays of light are also known as crepuscular rays, derived from the Latin word for “twilight”.
The Curiosity rover captured this breathtaking moment during its latest twilight cloud survey, which is building on its 2021 observations of noctilucent or night-shining clouds. According to NASA, while most Martian clouds hover no more than 37 miles above the ground and are composed of water ice, the clouds captured in the latest images appear to be at a higher altitude, where it’s especially cold. This suggests that these clouds are made of carbon dioxide ice or dry ice.
Just like on Earth, clouds on Mars provide scientists with crucial information for understanding the planet’s weather. By studying when and where clouds form, scientists can learn more about the Martian atmosphere’s composition and temperatures, as well as the winds within it.
The 2021 cloud survey included more imaging by Curiosity’s black-and-white navigation cameras, which provided a detailed look at a cloud’s structure as it moves. However, the recent survey, which began in January and will conclude in mid-March, relies more often on the rover’s color Mast Camera, or Mastcam. This camera helps scientists see how cloud particles grow over time.
In addition to the stunning image of the sun rays, Curiosity also captured a set of colorful clouds shaped like a feather on January 27th, 2023. These clouds, when illuminated by sunlight, can create a rainbow-like display called iridescence.
“Where we see iridescence, it means a cloud’s particle sizes are identical to their neighbors in each part of the cloud,” said Mark Lemmon, an atmospheric scientist with the Space Science Institute in Boulder, Colorado. “By looking at color transitions, we’re seeing particle size changing across 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 rays and iridescent clouds as panoramas, each of which was stitched together from 28 images sent to Earth. The images have been processed to emphasize the highlights and offer a closer look at the planet’s atmospheric phenomena.
The latest images captured by NASA’s Curiosity rover provide scientists with valuable insights into the Martian atmosphere, offering a better understanding of the planet’s weather patterns and atmospheric composition.