Free Astronomy Magazine July-August 2025

JULY-AUGUST 2025 a region of lakes and seas. Webb also has detected a key carbon-con- taining molecule that gives insight by NASA/ESA/CSA Christine Pulliam Evidence of cloud convection in Titan’s northern hemisphere S aturn’s moon Titan is an in- triguing world cloaked in a yel- lowish, smoggy haze. Similar to Earth, the atmosphere is mostly ni- trogen and has weather, including clouds and rain. Unlike Earth, whose weather is driven by evaporating and condensing water, frigid Titan has a methane cycle. NASA’s James Webb Space Telescope, supple- mented with images from the Keck II telescope, has for the first time found evidence for cloud convection in Titan’s northern hemisphere, over T he above four-panel infographic demonstrates a key chemical process believed to occur in the atmosphere of Saturn’s moon Titan. 1) Titan has a thick, nitro- gen (N 2 ) atmosphere that also contains methane (CH 4 ). 2) Molecules known as methyl radicals (CH 3 ) form when methane is broken apart by sunlight or energetic electrons from Saturn’s magnetosphere. 3) It then recombines with other mole- cules or with itself to make substances like ethane (C 2 H 6 ). 4) Methane, ethane and other molecules condense and rain out of the atmosphere, forming lakes and seas on Titan’s surface. NASA’s James Webb Space Telescope detected the methyl radi- cal on Titan for the first time, providing a key missing piece for our understanding of Titan’s chemical processes. [NASA, ESA, CSA, Elizabeth Wheatley (STScI)] into the chemical processes in Ti- tan’s complex atmosphere. On Ti- tan, methane plays a similar role to