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<\/p>\nBy combining data from the Keck II telescope and the joint NASA\/European Space Agency\/Canadian Space Agency James Webb Space Telescope, a group of scientists observed cloud convection in the northern hemisphere of Saturn\u2019s moon Titan \u2014 the first time such atmospheric activity has been observed in the region. A majority of Titan\u2019s methane lakes and seas are located in the northern hemisphere, meaning that they are likely constantly replenished by methane and ethane rain from clouds in that hemisphere.<\/p>\n
What\u2019s more, Webb\u2019s data was also used to detect a carbon-containing molecule within Titan\u2019s atmosphere. The molecule may provide planetary scientists with insight into the chemical processes that drive weather and other atmospheric phenomena on Titan.<\/p>\n<\/p>\n
Titan has been of substantial interest to planetary scientists for decades. The moon is remarkably similar to Earth, featuring a thick atmosphere with weather and a surface littered with small lakes and large seas. However, Earth and Titan differ drastically in the elemental composition of their atmospheres and surfaces. While the cycling of water drives Earth\u2019s weather, Titan\u2019s weather is driven by a methane cycle, meaning that Titan\u2019s lakes, seas, and clouds are filled with methane, not water.<\/p>\n
\u201cTitan is the only other place in our Solar System that has weather like Earth, in the sense that it has clouds and rainfall onto a surface,\u201d said lead author Conor Nixon of NASA\u2019s Goddard Space Flight Center in Maryland.<\/p>\n
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Comparison of Webb and Keck\u2019s imagery of Titan from July 2023. (Credit: NASA\/ESA\/CSA\/STScI\/Keck Observatory)<\/p>\n
Titan was observed numerous times by Webb at L2 and the ground-based W.M. Keck telescopes in Hawaii, specifically in November 2022 and July 2023. The telescopes identified clouds in the mid and high northern latitudes of the moon and observed these clouds rising to higher atmospheric altitudes over time. While clouds have been observed on Titan before, the observations provided the first evidence for cloud convection in Titan\u2019s northern hemisphere, which was experiencing summer at the time.<\/p>\n
As mentioned, most of Titan\u2019s lakes and seas are located within the moon\u2019s northern hemisphere. The evaporation of methane from the lakes likely results in the formation of the clouds seen in the Webb and Keck observations. The subsequent precipitation of methane from the clouds replenishes the liquid methane within the bodies of water.<\/p>\n
Nixon et al. utilized the telescopes\u2019 different sensitivities to infrared light to determine the altitude of the clouds. Due to its lower gravity, only about 14% that of Earth\u2019s, Titan\u2019s lower atmospheric layers expand. For example, Titan\u2019s troposphere, or the lowest layer of its atmosphere, extends to approximately 45 km altitude, whereas Earth\u2019s troposphere extends to only 12 km altitude. Due to the extended depth of Titan\u2019s atmospheric layers, the team was able to use different infrared filters on Webb and Keck to investigate the lower layers of the moon\u2019s atmosphere and measure the specific altitudes of the clouds.<\/p>\n
Space Technology (adsbygoogle = window.adsbygoogle || []).push({});<\/p>\n The team found that, over several days, the clouds would continue to rise in the atmosphere to higher and higher altitudes. Interestingly, though, no precipitation was observed.<\/p>\n \u201cWebb\u2019s observations were taken at the end of Titan\u2019s northern summer, which is a season that we were unable to observe with the Cassini-Huygens mission. Together with ground-based observations, Webb is giving us precious new insights into Titan\u2019s atmosphere that we hope to be able to investigate much closer-up in the future with a possible ESA mission to visit the Saturn system,\u201d said co-author Thomas Cornet of the European Space Agency (ESA).<\/p>\n<\/p>\n