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The James Webb Space Telescope has spied clouds on one of the most intriguing moons in the solar system.
In November, the space observatory turned its infrared gaze on Saturn’s largest moon, Titan. It is the only moon in our solar system to have a dense atmosphere, four times as dense as Earth’s.
Titan’s atmosphere is made of nitrogen and methane, giving it a fuzzy orange appearance. This thick haze prevents visible light from reflecting off the moon’s surface, making it difficult to distinguish features.
The Webb telescope observes the universe in infrared light, which is invisible to the naked eye: On November 5, the telescope detected a bright cloud in Titan’s northern hemisphere, and soon after, detected a second cloud in the atmosphere.
The largest cloud was located over Titan’s north polar region near the Kraken Mare, the largest known liquid sea of methane on the moon’s surface.
Titan has Earth-like liquid bodies on its surface, but its rivers, lakes, and seas are made of liquid ethane and methane, which form clouds and cause rain from the sky. Researchers also believe that Titan has an internal ocean of liquid water.
“The cloud detection is exciting because it validates the long-standing predictions of Titan’s climate computer models that clouds would easily form in the mid-Northern Hemisphere during late summer when the Sun warms the surface,” says Conor. Nixon, a planetarium. scientist at NASA Goddard Space Flight Center in Greenbelt, Maryland, on NASA web blog.
Nixon is also the principal investigator in the Webb observing program for Titan.
The team of astronomers studying Webb’s observations contacted their colleagues at the WM Keck Observatory in Hawaii to see if follow-up observations could reveal whether the clouds were moving or changing shape.
“We were concerned that the clouds had disappeared when we looked at Titan two days later with Keck, but to our delight there were clouds in the same positions, which seemed to have changed shape,” said Imke de Pater, professor emeritus of astronomy at the University of California, Berkeley, and Keck Titan observation team leader, in a statement.
Atmospheric model experts helped the team determine that the two telescopes had captured observations of seasonal weather patterns on Titan.
Webb’s near-infrared spectrograph instrument was also able to collect data on Titan’s lower atmosphere, which cannot be seen by ground-based observatories. as Keck due to interference from the Earth’s atmosphere, at different wavelengths of infrared light.
The data, which is still being analyzed, was able to penetrate deeper into Titan’s atmosphere, see, and surface than the Cassini spacecraft, which orbited Saturn and its moons for 13 years. Webb’s observations could also reveal the cause of a bright feature over Titan’s south pole.
Cloud observations were a long time coming.
“We had waited for years to use Webb’s infrared vision to study Titan’s atmosphere, including its fascinating weather patterns and gaseous composition, and also to see through the haze to study surface albedo features,” Nixon said. , referring to the bright and dark patches. .
“Titan’s atmosphere is incredibly interesting, not only because of its methane clouds and storms, but also because of what it can tell us about Titan’s past and future, including whether it always had an atmosphere. We were absolutely delighted with the initial results.”
The team is planning more observations of Titan in June that may provide additional information about the gases in its atmosphere.
