Researchers studying the Great White Spot, a mega-storm on Saturn that mysteriously comes and goes every few decades, have discovered why the storm appears and then vanishes for years. Every 30 years since humans began recording it using telescopes 140 years ago, a giant storm appears on Saturn and then vanishes, totaling six times so far. The mystery has been solved in a new report in the journal Natural Geoscience led by graduate student and the California Institute of Technology Cheng Li, in which the researchers explain that water vapor is the culprit.
What makes a storm is convection: the process of hot air rising and cold air sinking, a churning that creates storms. The report explains that water molecules are heavier than the hydrogen and helium molecules that dominate Saturn’s atmosphere, so when they sink to the bottom, they form a layer that stays for about 30 years, because they are simply too wet and dense to rise. Once enough heat from the lighter upper atmosphere dissipates into space, the upper atmosphere cools, becoming denser than the once-cooler lower atmosphere, and the two begin to trade places, creating convection.
Li explained that Saturn is known to have a volatile, temper tantrum atmosphere, unlike a planet such as Jupiter. The report shows that an abundance of water vapor is what can cause such a disruptive atmosphere. If Saturn’s deep atmosphere were drier, more frequent yet smaller storms would occur, such as on Jupiter. The significantly wet atmosphere of Saturn instead creates periodic powder keg explosions.
What Li and his team are most interested about with the study is understanding the formation of the early solar system. Li noted that Saturn and Jupiter are thought to be the oldest of all the planets, so understanding their behavior will provide a critical look into the evolution of planetary bodies at large. NASA’s Juno spacecraft is currently making an adventure to Jupiter and is set to arrive in 2016, which will allow Li to see how much water is in Jupiter’s atmosphere to further corroborate his water vapor theory.
Some of the earth reminds one of a temper tantrum — but the tranquility of some of Earth is most definitely something else: