Although the James Webb Space Telescope was built primarily for looking back at the earliest and most distant galaxies, it can also be used for a host of other scientific observations — including looking at targets right here in our own solar system. Webb will perform a major study of Jupiter and has already imaged Neptune. Now, Webb has been used to get a fascinating look at our planetary neighbor, Mars.
It’s actually pretty difficult for Webb to study Mars because it is so close, and therefore very bright in both the visible light portion of the spectrum and in the infrared wavelengths at which Webb observes. The brightness can oversaturate the detectors which are designed to pick up very faint light sources. But Webb’s NIRCam camera was able to capture the martian surface, with two images captured at different wavelengths shown below.
Recommended Videos
Webb’s first images of Mars, captured by its NIRCam instrument Sept. 5, 2022 [Guaranteed Time Observation Program 1415]. Left: Reference map of the observed hemisphere of Mars from NASA and the Mars Orbiter Laser Altimeter (MOLA). Top right: NIRCam image showing 2.1-micron (F212 filter) reflected sunlight, revealing surface features such as craters and dust layers. Bottom right: Simultaneous NIRCam image showing ~4.3-micron (F430M filter) emitted light that reveals temperature differences with latitude and time of day, as well as darkening of the Hellas Basin caused by atmospheric effects. The bright yellow area is just at the saturation limit of the detector.NASA, ESA, CSA, STScI, Mars JWST/GTO teamThe shorter wavelength image, shown at the top, is similar to a visible light image and shows features like craters and basins. The longer wavelength image, shown below, shows how the planet is radiating heat. The brightest spot is where the sun is directly overhead, with cooler regions toward the poles. The Hellas Basin also appears darker, though this isn’t because of temperature effects but rather due to the effects of altitude and air pressure.
Webb was also able to capture Mars using its spectrometry instruments. These can split light into different wavelengths to see the composition of an object — in this case, looking at the composition of the martian atmosphere as a whole. There are clear indications of carbon dioxide, water, and carbon monoxide, and what is impressive about this is how well the data fits the model of what we already know about Mars’s atmosphere. This shows just how effective Webb’s instruments are for this kind of spectrometry work — and how effective Webb has the potential to be when looking into the atmospheres of exoplanets.
Webb’s first near-infrared spectrum of Mars, captured by the Near-Infrared Spectrograph (NIRSpec) Sept. 5, 2022, as part of the Guaranteed Time Observation Program 1415, over 3 slit gratings (G140H, G235H, G395H). The spectrum is dominated by reflected sunlight at wavelengths shorter than 3 microns and thermal emission at longer wavelengths. Preliminary analysis reveals the spectral dips appear at specific wavelengths where light is absorbed by molecules in Mars’ atmosphere, specifically carbon dioxide, carbon monoxide, and water. Other details reveal information about dust, clouds, and surface features. By constructing a best-fit model of the spectrum, for example, the Planetary Spectrum Generator, abundances of given molecules in the atmosphere can be derived.NASA, ESA, CSA, STScI, Mars JWST/GTO team
The research using this Webb data is still being worked on and has not yet been published or peer-reviewed, so it shouldn’t be taken as definitive. But it goes to show just how versatile a tool Webb can be, with more Webb data on Mars still to come.
Mysterious colorful clouds drift through Mars’s sky in new Curiosity images
As the Curiosity rover explores its way around Mars, it isn't only looking down at the martian rocks and regolith -- it is also looking up at the martian sky. Like Earth, Mars has its own seasonal weather patterns, but with its different atmosphere that weather can include some unusual phenomena, such as striking colorful clouds.
A recent video created from images captured by Curiosity shows clouds tinted red and green flowing though the sky over Mars. Captured using the rover's Mastcam instrument on January 17, 2025, the video shows the clouds during twilight on the red planet.
James Webb to join observations of asteroid that could strike Earth in 2032
If you've been following the story of an asteroid that could hit Earth in 2032, there's bad news and good news. The bad news is that the likelihood of the asteroid striking the Earth has now risen slightly, but the good news is that astronomers are using tools like the James Webb Space Telescope to track it in more detail.
The probability that Asteroid 2024 YR4 will impact Earth on December 22, 2032 has now risen to 2.3%, according to NASA. The asteroid is being observed by ground-bases telescopes that are part of the International Asteroid Warning Network, which will be following the it for as long as it continues to be visible -- which should be through April this year. After that, it will be too faint to observe until 2028.
Gorgeous James Webb Space Telescope images land on new U.S. stamps
In a mark of its huge impact on the world of science and astronomy, NASA’s James Webb Space Telescope finds itself once again as the inspiration for a new set of stamps from the United States Postal Service (USPS).
Two new stamps issued this month feature iconic images captured by Webb, one of them showing a spiral galaxy called NGC 628. “Webb’s observations combine near- and mid-infrared light to reveal glowing gas and dust in stark shades of orange and red, as well as finer spiral shapes with the appearance of jagged edges,” NASA said of the image (below), adding that the galaxy is located 32 million light-years away in the Pisces constellation.
