Understanding Saturn's moon Titan's seasons might provide insights about Earth's climate

Researchers have found that Saturn’s largest moon Titan undergoes significant seasonal changes in its energy budget — the amount of solar energy it absorbs, and the heat it emits — an advance that may lead to new insights about climate fluctuations on the Earth. The study, published in the journal Geophysical Research Letters, noted that Titan is the only body in the solar system, other than Earth, with a significant atmosphere and liquid surface lakes. The researchers, including those from the University of Houston in the US, said Titan’s dynamically-varying energy budget has important impacts on its weather and climate systems. As part of the study, the scientists used data collected from the Cassini mission between 2004 and 2017. [caption id=“attachment_7527681” align=“alignnone” width=“1280”] Cassini spacecraft catches a glimpse of bright sunlight reflecting off the hydrocarbon seas of Saturn’s large moon Titan. Image: NASA[/caption] They said this data pertained to the equivalent of about half an Earth year for Saturn and Titan, or portions of three seasons. According to the researchers, the data provided the first opportunity to systematically examine the seasonal variations of Titan. Both the moon’s emitted thermal energy and absorbed solar energy decreased over the 14-year period, the study noted. However, they said the thermal emission from Titan dropped less — about 6.8 percent — compared with an 18.6 percent drop in solar energy it received. The study noted that this varied between the northern and southern atmospheres of Titan, and also depended on the moon’s distance from the sun during its orbit. While there are some parallels that could be drawn to study similar effects on the Earth, the researchers said our planet and Titan also differed drastically in several ways. The researchers said the surface liquid on Titan is liquid methane, rather than water, for example, and explained that it takes Saturn and its moons far longer to complete an orbit around the Sun. It takes Saturn about 29 Earth years to complete its orbit, said Liming Li, a physics professor at UH and corresponding author on the paper. Still, the researchers said, learning more about the energy budget of Titan can add to the understanding of climate change on Earth. “Earth’s small energy imbalance has significant effects on its global warming and climate change,” Liming said. “We expect that the dynamically-varying energy budget and the possible energy imbalance have important impacts on the weather and climate systems on Titan,” he added.