Researchers from the University of Bristol and NASA have discovered that the atmosphere of Titan, Saturn’s largest moon, doesn’t behave the way scientists have assumed for decades. Instead of synchronized rotation with the surface, it oscillates like a gyroscope, obeying seasonal rhythms that last almost 30 Earth years!
Titan is a unique world in the solar system. It is the only moon with a dense atmosphere that resembles Earth’s early in its evolution and is composed primarily of nitrogen and methane. But a new analysis of data from the Cassini-Huygens mission has revealed: its air envelope is not just spinning, but moving independently of the surface. Using archival infrared observations from the CIRS spectrometer, scientists have found that the temperature field of the atmosphere is shifting relative to the poles.
“Titan’s atmosphere appears to be acting like a gyroscope, stabilizing itself in space,” explains study author Dr. Lucy Wright.
Mystery of the stability of long seasons
The seasons on Titan change extremely slowly. Therefore, one year on Titan lasts almost 30 Earth years. And the change of seasons affects the fluctuations of the atmosphere. The most amazing thing is that the direction of the tilt of the atmosphere remains constant relative to space — it is not changed by the gravity of either the Sun or Saturn.
“This is a new mystery. We thought external forces would influence orientation, but it’s different,” adds Professor Nick Teanby.
Scientists suggest that some time ago the atmosphere was knocked off its axis by an unknown catastrophic event, and now it is slowly stabilizing like a spinning top ripped by strong kinetic energy.
Dragonfly mission
The discovery is critical to NASA’s future Dragonfly mission, a helicopter drone that is set to explore Titan in the middle of the next decade. Its descent through the atmosphere requires precise calculations: the local winds move 20 times faster than the spin of the moon!
“Atmospheric fluctuations affect the trajectory of the vehicle. We will now take this data into account to accurately predict the landing site,” commented NASA’s Dr. Conor Nixon.
The Cassini archives continue to reveal secrets years after the mission ended. And the study of Titan not only expands knowledge of the solar system, but also provides clues to understanding the physics of Earth’s and other planets’ atmospheres. “It’s a reminder: nature always knows how to surprise us,” concludes Lucy Wright.
We previously reported on how Titan has a methane crust 10 kilometers thick.
According to sci.news
