Two ultraviolet images of Mars, taken six months apart
The two images to the right, rearranged, cropped, and reduced to post here, were taken six months apart by the Mars orbiter MAVEN using its Imaging Ultraviolet Spectrograph (IUVS). From the press release:
The IUVS instrument measures wavelengths between 110 and 340 nanometers, outside the visible spectrum. To make these wavelengths visible to the human eye and easier to interpret, the images are rendered 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.
The first image [top] was taken in July 2022 during the southern hemisphere’s summer season, which occurs when Mars passes closet to the Sun. The summer season is caused by the tilt of the planet’s rotational axis, similar to seasons on Earth. 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 visible 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.
The second image [bottom] is of Mars’ northern hemisphere and was taken 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 can be seen 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. It is then destroyed in northern spring by chemical reactions with water vapor, which is restricted to low altitudes of the atmosphere at this time of year.
Though of course not visible, the landing sites for Viking-1 (1976), Pathfinder (1997), and Franklin (2028) are captured in the bottom global image, as indicated by the white dots I have added. The two left dots are Viking-1 and Pathfinder respectively, located in the northern lowland plain dubbed Chryse Planitia. Franklin will land to the right, in the transition zone between those northern lowland plains and the southern cratered highlands.
The two images to the right, rearranged, cropped, and reduced to post here, were taken six months apart by the Mars orbiter MAVEN using its Imaging Ultraviolet Spectrograph (IUVS). From the press release:
The IUVS instrument measures wavelengths between 110 and 340 nanometers, outside the visible spectrum. To make these wavelengths visible to the human eye and easier to interpret, the images are rendered 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.
The first image [top] was taken in July 2022 during the southern hemisphere’s summer season, which occurs when Mars passes closet to the Sun. The summer season is caused by the tilt of the planet’s rotational axis, similar to seasons on Earth. 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 visible 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.
The second image [bottom] is of Mars’ northern hemisphere and was taken 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 can be seen 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. It is then destroyed in northern spring by chemical reactions with water vapor, which is restricted to low altitudes of the atmosphere at this time of year.
Though of course not visible, the landing sites for Viking-1 (1976), Pathfinder (1997), and Franklin (2028) are captured in the bottom global image, as indicated by the white dots I have added. The two left dots are Viking-1 and Pathfinder respectively, located in the northern lowland plain dubbed Chryse Planitia. Franklin will land to the right, in the transition zone between those northern lowland plains and the southern cratered highlands.
