Astronomers have made exciting discoveries on Titan, Saturn’s largest moon, including recently detecting cloud convection near lakes and seas on Titan’s surface. This discovery, made in the northern hemisphere where most of Titan’s lakes and seas are located, reveals critical aspects of Titan’s complex weather patterns and methane cycle. In addition to furthering scientific discovery, the findings will enhance the scientific community’s understanding of organic chemistry in relation to astrobiology.
Titan has a very dense atmosphere, rich in nitrogen, but in methane. This strange combination creates a very active troposphere that extends far above the surface—up to 27 miles (45 kilometers) high. In this extreme setting, intense sunlight and energetic electrons from Saturn’s magnetosphere bust up methane molecules. This step is responsible for the formation of methyl radicals. These radicals play a crucial role in Titan’s weather system, as they contribute to the condensation of methane and ethane, which subsequently rain out, forming lakes and seas on the moon’s surface.
Titan’s methane cycle works similarly to Earth’s water cycle. Just as water evaporates, condenses, and precipitates on Earth, methane does the same cycle on Titan’s surface. The cloud convection just observed directly completes the cycle and provides a key piece of the puzzle to this complex process. In real time, during the over four days of the field campaign, scientists were able to observe clouds seemingly being sucked up to greater heights by powerful atmospheric dynamics.
Evaporation from Titan’s lakes provides an important avenue of methane production. This process is hard to separate from the resulting relationship between its atmospheric and surface features. The observations raise some very interesting questions regarding Titan’s meteorology. It has clouds and rain mostly of methane.
Scientists are especially interested in Titan’s dense atmosphere and its varied, Earth-like weather phenomena. They are especially excited to check out the organic molecules littering its surface. These carbon-containing compounds are the literal building blocks of all life on Earth. Scientists are exploring the mysterious organic chemistry found on Titan. At the same time, they work to discover the processes that might have initiated the beginning of life.
This yellowish, smoggy haze that cloaks Titan only adds to its mystery, making the world seem all the more intriguing and ripe for exploration. Astronomers have turned to studying the atmospheric dynamics and complex chemistry of this enigmatic moon. As they research it, we’ll be learning new things about its potential to hold life.