The largest storm observed in the solar system, stretching more than 16,<> kilometers wide, called the Great Red Spot, adorned the surface of Jupiter for hundreds of years, and was thought to be unparalleled in our solar system.
But a new study shows that Saturn also has long-lasting superstorms with deep atmospheric impacts that have lasted for centuries.
According to a press release published on the Yorick Alert website on August 11, the study was conducted by a team of astronomers from the University of California, Berkeley, and the University of Michigan, Ann Arbor, who studied radio emissions from the planet, which come from beneath the surface, and found long-term disruptions in the distribution of ammonia gas. The study was published in the journal Science Advances.
Giant storms occur on Saturn approximately every 20 to 30 years (Emmicky de Peter – University of California, Berkeley)
Saturn and the giant planets
Giant storms occur on Saturn about every 20 to 30 years, and are similar to hurricanes on Earth, but much larger.
Unlike Earth's hurricanes, no one knows why massive storms occur in Saturn's atmosphere, which consists mainly of hydrogen and helium with traces of methane, water and ammonia.
Lead author Cheng Li, a former fellow at the University of California and now an assistant professor at the University of Michigan, said: "Understanding the mechanisms of the solar system's largest storms places the theory of hurricane occurrence in a broader cosmic context, challenging our current knowledge and pushing the boundaries of geometeorology."
The research team used radio emissions from deep inside the planet to study the gas giants (Jupiter and Saturn) observed by the very large Carl G. Jansky array in New Mexico.
The researchers say they have sought to study beneath the visible cloud layers on giant planets, and because chemical reactions and dynamics change the composition of the planet's atmosphere, studying what goes on beneath these cloud layers is required to determine the true composition of the planet's atmosphere.
Radio observations have helped them characterize dynamic, physical and chemical processes including thermal transport, cloud formation and convection in the atmosphere of giant planets at global and local scales."
The team used radio emissions from the depths of Saturn to study the impact of storms (RJ Salt – Emekke de Peter)
Storms and ammonia concentration
As reported in the new study, the team found something surprising in radio emissions from the planet, as they found anomalies in the concentration of ammonia gas in the atmosphere, which they concluded were related to events prior to massive storms in the northern hemisphere of the planet.
According to the team, they found that the ammonia concentration is lower at the middle altitudes, below the upper cloud layer consisting of ammonia and ice, but has become dense at low altitudes, 100 to 200 kilometers into the atmosphere.
Researchers believe that ammonia is transported from the upper atmosphere to the lower atmosphere via sedimentation and re-evaporation processes. Moreover, this effect can last for hundreds of years.
The study also revealed that although both Saturn and Jupiter are made of hydrogen gas, these two gas giants differ markedly.
While Jupiter has an anomaly in the troposphere of its atmosphere, this anomaly is related to its range (white lines) and belts (dark lines) on its surface, not caused by storms as in Saturn.
The significant difference between adjacent gas giants presents a challenge to what scientists know about the formation of giant storms in gas giants and other planets, so identifying and understanding what those differences are will be useful in studying similar exoplanets.