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.
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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.
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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.
James Webb discovers a new type of exoplanet: an exotic ‘steam world’
Our solar system has a wide variety of planet types, from tiny rocky Mercury to huge puffy gas giant Jupiter to distant ice giant Uranus. But beyond our own system, there are even more types of exoplanet out there, including water worlds covered in ocean and where life could potentially thrive. Now, researchers using the James Webb Space Telescope have identified a new and exotic type of planet called a steam world, which has an atmosphere almost entirely composed of water vapor.
The planet, called GJ 9827 d, was examined by the Hubble Space Telescope earlier this year and had researchers so intrigued that they wanted to go back for a closer look using Webb. They found that the planet, which is around twice the size of Earth, had a very different atmosphere from the typical hydrogen and helium that is usually seen. Instead, it was full of hot steam.
‘That’s weird’: This galaxy could help astronomers understand the earliest stars
Astronomers using the James Webb Space Telescope have spotted a weird galaxy that originated just a billion years after the Big Bang. Its strange properties are helping researchers to piece together how early galaxies formed, and to inch closer to one of astronomy's holy grail discoveries: the very earliest stars.
The researchers used Webb's instruments to look at the light coming from the GS-NDG-9422 galaxy across different wavelengths, called a spectrum, and made some puzzling findings.
Elon Musk shares new target date for Starship voyage to Mars
SpaceX is aiming to launch “about five” uncrewed Starship voyages to Mars in two years’ time, according to a post on X (formerly Twitter) by CEO Elon Musk on Sunday.
Musk said that if the uncrewed missions land safely on the red planet, then the first crewed mission could take place as early as 2028, but he added that “if we encounter challenges, then the crewed missions will be postponed another two years” due to the alignment of Earth and Mars that makes such journeys possible. He continued: “We want to enable anyone who wants to be a space traveler to go to Mars! That means you or your family or friends -- anyone who dreams of great adventure. Eventually, there will be thousands of Starships going to Mars and it will a glorious sight to see! Can you imagine? Wow.”
