The James Webb Space Telescope (JWST) has released its first images of Mars, providing a more detailed look at the red planet’s atmosphere. By sunshine.
The first web images of Mars were captured by the Near Infrared Camera (NIRCam), which depicts a region of the planet’s eastern hemisphere at two different wavelengths, or infrared light colors.
The Red Planet is one of the brightest objects in the night sky due to its relative proximity to Earth, but this presents challenges for the JWST, which was built to detect the faint light from distant galaxies in the universe.
The first image shows a surface reference map from NASA and the Mars Orbiter Laser Altimeter (MOLA) on the left, overlaying the field-of-view of the Webb NIRCam instrument.
Reflected sunlight dominates the shorter-wavelength NIRCam image, thus revealing surface details similar to those seen in visible-light images.
The rings of the Huygens Crater (the planet’s fifth largest impact crater named after astronomer Christian Huygens), the dark igneous rocks of Sirtes Major (a well-known dark spot), and brightness in the Hellas Basin are all visible in this image.
The space agency notes that the basin is the largest, well-preserved impact structure on Mars, spanning more than 1,200 miles.
When light from the planet passes through the Martian atmosphere, some of it is absorbed by carbon dioxide (CO2) molecules, making the Hellas Basin appear darker than the surrounding areas due to this effect.
“This is actually not a heat effect in Hellas,” explains lead researcher Jeronimo Villanueva of NASA’s Goddard Space Flight Center, who designed these Webb observations.
The Hellas Basin is located at a lower elevation and is therefore subjected to higher air pressure, and this higher pressure suppresses heat emission at this specific wavelength range due to an effect called pressure expansion.
Villanueva and his team also released the first Mars near-infrared spectrum from Webb, which shows minute differences in brightness between hundreds of different wavelengths.
“Initial analysis of the spectrum shows a rich set of spectral features that contain information about dust, ice clouds, the type of rock on the planet’s surface, and the composition of the atmosphere,” NASA says.
The US space agency also noted that Webb’s instruments are so sensitive that they require special techniques to avoid the so-called “detector saturation” due to the bright infrared light coming from Mars.