WASHINGTON — Jupiter’s turbulent beauty comes from its wild atmosphere full of storms, artfully swirling clouds and big bands of color wrapping around the gas giant. But astronomers wanted to understand what’s happening beneath those thick clouds to cause the storms and eruptions.
Astronomers used six ground-based telescopes and NASA’s Hubble Space Telescope in January 2017 to capture views of Jupiter in visible light and radio waves.
Jupiter’s atmosphere is made up of hydrogen and helium, two of the most abundant elements in the universe, with a sprinkling of methane, ammonia, hydrogen sulfide and water.
The telescopes were able to provide a unique view all the way down to 31 miles above the cloud deck. The top cloud layer is ammonia ice, followed by a layer of solid ammonium hydrosulfide particles. The visibly stunning belts of white and brown zones are due to variations in composition. Below this upper cloud deck is a liquid water cloud layer.
The observations were included in a study that has been accepted for publication in the Astronomical Journal.
“ALMA enabled us to make a three-dimensional map of the distribution of ammonia gas below the clouds. And for the first time, we were able to study the atmosphere below the ammonia cloud layers after an energetic eruption on Jupiter,” said Imke de Pater, study author and professor emerita of astronomy at the University of California, Berkeley.
They were able to track the storms inside Jupiter’s colorful belts, much like we track them on Earth, and realized the storms create plumes above the ammonia ice clouds. These appear as bright points on the planet’s colorful belts. The storms also contained lightning. When the storm clouds reach the coldest part of the atmosphere, they spread out like cumulonimbus clouds that cause lightning and thunder on Earth.
The bright plumes create disruptions in the belts that can last for months or even years. “If these plumes are vigorous and continue to have convective events, they may disturb one of these entire bands over time, though it may take a few months,” de Pater said. “With these observations, we see one plume in progress and the aftereffects of the others.”
The observations occurred when an amateur astronomer named Phil Miles in Australia spied an eruption on the South Equatorial Belt, first as a small bright plume that was followed by a larger disruption in the belt that lasted for weeks. The Atacama Large Millimeter/submillimeter Array in Chile captured the view of the atmosphere below the plumes in radio waves, which was compared to other visible light and infrared images captured by other telescopes simultaneously.
“Our ALMA observations are the first to show that high concentrations of ammonia gas are brought up during an energetic eruption,” de Pater said. “This led us to confirm the current theory that energetic plumes are triggered by moist convection at the base of water clouds, which are located deep in the atmosphere. The plumes bring up ammonia gas from deep in the atmosphere to high altitudes, well above the main ammonia cloud deck.”