Mars in ultraviolet: New hues for the red planet

NASA published this original article on June 22, 2023. Edits by EarthSky.

Mars in ultraviolet

NASA’s MAVEN (Mars Atmosphere and Volatile EvolutioN) mission has released stunning new views of Mars. MAVEN acquired these ultraviolet images at different points along the red planet’s orbit around the sun. By viewing the planet in ultraviolet wavelengths, scientists can gain insight into the Martian atmosphere and view surface features in remarkable ways. MAVEN’s Imaging Ultraviolet Spectrograph (IUVS) instrument obtained these global views of Mars in 2022 and 2023, when the planet was near opposite ends of its elliptical orbit.

The IUVS instrument measures wavelengths between 110 and 340 nanometers, outside the visible spectrum. Scientists had to make these wavelengths visible to the human eye and easier to interpret. Therefore, they rendered the images with the varying brightness levels of three ultraviolet wavelength ranges represented as red, green, and blue. In this color scheme, atmospheric ozone appears purple, while clouds and hazes appear white or blue. The surface can appear tan or green, depending on how the images have been optimized to increase contrast and show detail.

MAVEN took the first image (above) in July 2022. This was during the southern hemisphere’s summer season, which occurs when Mars passes closest to the sun. The tilt of the planet’s rotational axis causes the seasons on Mars. It’s the same way Earth experiences the seasons.

Argyre Basin, one of Mars’ deepest craters, appears at bottom left filled with atmospheric haze (depicted here as pale pink). The deep canyons of Valles Marineris appear at top left filled with clouds (colored tan in this image). The southern polar ice cap is at bottom in white, shrinking from the relative warmth of summer. Southern summer warming and dust storms drive water vapor to very high altitudes, explaining MAVEN’s discovery of enhanced hydrogen loss from Mars at this time of year.

Another view of the red planet in new colors

The second image is of Mars’ northern hemisphere. MAVEN acquired this image in January 2023, after Mars had passed the farthest point in its orbit from the sun. The rapidly changing seasons in the north polar region cause an abundance of white clouds. The deep canyons of Valles Marineris are in tan at lower left, along with many craters. Ozone, which appears magenta in this UV view, has built up during the northern winter’s chilly polar nights. Then, in northern spring, chemical reactions with water vapor destroy the ozone. Water vapor is restricted to low altitudes of the atmosphere at this time of year.

MAVEN launched in November 2013 and entered Mars’ orbit in September 2014. The mission’s goal is to explore the planet’s upper atmosphere, ionosphere and interactions with the sun and solar wind. Scientists want to learn more about the loss of the Martian atmosphere to space. Understanding atmospheric loss gives scientists insight into the history of Mars’ atmosphere and climate, liquid water and planetary habitability. The MAVEN team is preparing to celebrate the spacecraft’s 10th year at Mars in September 2024.

Bottom line: The MAVEN spacecraft acquired two new images of Mars in ultraviolet. These new views help us get a different perspective on the planet next door.

Via NASA

Read more: Mars in 2023: Fading dramatically in June