Scientists have detected surprising anomalies in Saturn’s atmosphere. Their likely cause is the storms that occurred hundreds of years ago in the gas giant’s northern hemisphere.
Saturn is the sixth planet of the solar system and the second largest. It is most distinctive because of the ice-rocky rings that surround it. And although Jupiter is considered the most “stormy” celestial body because of the huge anticyclone called the Great Red Spot, it is not too calm on Saturn either.
According to the latest research, megastorms also occur on Saturn, which can persist for centuries.
Disturbances in emission
The study, which appeared on Friday in the scientific journal Science Advances, was carried out by astronomers from the University of California, Berkeley and the University of Michigan. Using radio telescopes, scientists wanted to see what was happening on the planet after stormwhich was observed in 2010. Instead, evidence was found that there were still traces of events in Saturn’s atmosphere that had happened in 1876, and perhaps even earlier.
Saturn’s atmosphere is mostly hydrogen and helium, but also methane, water, and ammonia. Every 20-30 years, megastorms occur in it, resembling terrestrial hurricanes, but on a much larger scale. However, scientists cannot say what causes them.
“Understanding the mechanisms behind the formation of the largest storms in the solar system gives the hurricane theory a broader, cosmic context and challenges our current understanding, pushing the boundaries of terrestrial meteorology,” said lead author Cheng Li.
– Thanks radio waves we probe low cloud layers on giant planets. Because chemical reactions and dynamics change the composition of a planet’s atmosphere, their observations are essential to determine the true composition of a planet’s atmosphere – a key parameter for models of celestial body formation. Radio observations help characterize dynamic, physical and chemical processes, including heat transport, cloud formation and convection in the atmospheres of gas giants, explained Imke de Pater, who has been studying the outer planets of the solar system for over 40 years using the Very Large Array radio telescopes in New Mexico.
It falls and rises
Together with Chris Moeckel, de Pater and Li discovered a surprising anomaly in ammonia emissions in Saturn’s atmosphere. They linked it to megastorms that have occurred in the past in the northern hemisphere of the planet.
The researchers found that ammonia concentrations are lower at mid-altitude, just below the top layer of the ammonia-ice clouds, and higher – about 100-200 kilometers deeper in the atmosphere. They found that the chemical is transported through precipitation and re-evaporation.
– On Earth, when it rains heavily, water collects in puddles. But on giant planets that have no surface, where is it supposed to accumulate? It just evaporates,” Li said.
This phenomenon can persist for hundreds of years.
“We know that storms are large, but based on our experience with the weather, we have never considered the possibility that they could leave an impact lasting hundreds of years. On Earth, the weather comes and goes, and on Saturn, it stays the same,” Li added.
The way the anomalies have behaved since storm activity could help scientists learn more about Saturn’s weather.
The study also revealed that although Jupiter and Saturn – the solar system’s two largest planets – are made up of hydrogen, they are actually quite different. And although Jupiter also has anomalies in the atmosphere, they are related to the presence of “zones” (white bands) and “bands” (dark bands) rather than, as in the case of Saturn, storms. The latest discovery challenges existing knowledge about gas giants and other planets, suggesting that the “atmospheric phenomena” that occur on them may have different causes and effects.
Main photo source: NASA/ESA/Amy Simon (NASA-GSFC)/Alyssa Pagan (STScI)