Webb Confirms Seasonal Variations in Titan Climate Model

Of all the alien worlds in our solar system, one in particular resembles our home planet. Titan, the largest moon of Saturn, is the only other place we know of where you could walk along the seashore or stand in the rain. However, Titan’s exotic seas and its oily raindrops are not made of water, but of the natural gases methane and ethane, super-chilled into liquid form.

This global circulation model simulates a year of weather on Titan, depicting seasonal variations in wind currents, methane cloud cover, and sunlight over the course of a Saturn year (approximately 29.5 Earth years). Beginning with the vernal equinox, the Sun’s light gradually increases in the northern hemisphere as Titan’s lake country enters summer. Methane evaporates from hydrocarbon seas rivaling the Great lakes of North America and rises into the atmosphere, propelled upward by meridional (north-south) wind currents in the northern mid-latitudes. As the rising methane cools, it condenses into large rain clouds. These clouds in Titan's northern hemisphere were first observed by NASA’s James Webb Space Telescope in 2022, confirming the model's hypothesis.

Following northern summer, sunlight migrates southward and the meridional wind currents reverse direction, causing cold air to sink in the northern mid-latitudes. As autumn gives way to winter, a polar hood of high-altitude clouds settles over the northern regions, blocking them from view. The simulation ends with sunlight moving northward once again for a new vernal equinox – completing a full cycle of seasons at Titan.