The Webb Telescope spied clouds beneath the haze on Saturn’s moon Titan
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The James Webb Space Telescope has spotted clouds on one of the Solar System’s most intriguing moons.
In November, the space observatory turned its infrared gaze on Saturn’s largest moon, Titan. It is the only moon in our solar system that has a dense atmosphere – four times as dense as Earth’s.
Titan’s atmosphere is made up of nitrogen and methane, giving it a fuzzy, orange appearance. This dense haze obscures visible light by reflecting off the moon’s surface, making features difficult to discern.
The Webb telescope observes the universe in infrared light, which is invisible to the human eye – on November 5, the telescope spotted a bright cloud in Titan’s northern hemisphere and soon after discovered a second cloud in the atmosphere.
The larger 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 liquid water ocean.
“The discovery of clouds is exciting because it confirms long-standing predictions from computer models of Titan’s climate that clouds would form readily in the mid-northern hemisphere during late summer when the surface is warmed by the Sun,” wrote Connor Nixon, a planetary scientist. at NASA’s Goddard Space Flight Center in Greenbelt, Maryland, on NASA’s Webb Blog.
Nixon is also the principal investigator by the Webb observing program on Titan.
The team of astronomers studying the Webb observations contacted 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 would disappear when we looked at Titan two days later with Keck, but to our delight there were clouds in the same positions, looking as if they had changed shape,” said Imke de Pater, professor emeritus of astronomy at University of California, Berkeley, and leader of the Keck Titan observation team, in a statement.
Atmospheric modeling experts helped the team determine that the two telescopes had captured observations of Titan’s seasonal weather patterns.
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, in different wavelengths of infrared light.
The data, which is still being analyzed, was able to see deeper into Titan’s atmosphere 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’ve been waiting years to use Webb’s infrared vision to study Titan’s atmosphere, including its fascinating weather patterns and gas composition, and also to see through the haze to study the albedo characteristics of the surface,” said Nixon, considering the bright and dark spots.
“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 plans more observations of Titan in June, which could provide additional information about the gases in its atmosphere.