Siegelman identified the connection between Earth and Jupiter in 2018 when she noticed similarities between images of Jupiter"s cyclones and the ocean turbulence she was studying. "Jupiter is basically an ocean of gas," Siegelman said, explaining that physicists consider both air and water as fluids, making the application of ocean physics to Jupiter logical.
This observation led Siegelman to co-author a 2022 study published in Nature Physics, analyzing high-resolution infrared images of Jupiter"s cyclones taken by NASA"s Juno spacecraft. The analysis showed that a type of convection seen on Earth helps sustain Jupiter"s storms, which can span thousands of miles and last for years.
The 2022 study concentrated on Jupiter"s cyclones, but Siegelman also noticed filaments, or wispy tendrils, in the gaps between the vortices. These filaments resembled Earth"s oceanic and atmospheric processes. Siegelman used Juno"s detailed imagery to determine if this resemblance was significant.
Siegelman"s follow-up study, published on June 6 in Nature Physics and funded by Scripps and the National Science Foundation, finds further similarities between the processes driving Jupiter"s cyclones and those on Earth. The study reveals that the filaments between Jupiter"s cyclones act together with convection to maintain the planet"s massive storms. Specifically, Jupiter"s filaments resemble what oceanographers and meteorologists call fronts on Earth.
Fronts, commonly mentioned in weather forecasts, apply to both gases and liquids. They represent boundaries between gas or liquid masses with different densities due to temperature differences. In oceans, fronts can also result from salinity variations, which, along with temperature, influence seawater density. A key characteristic of fronts is their leading edges, which feature strong vertical velocities that can generate winds or currents.
To understand the role of the filaments between Jupiter"s cyclones in Juno"s images, Siegelman examined a series of infrared images of Jupiter"s north polar region taken in 30-second intervals. The infrared images allowed Siegelman and her co-author Patrice Klein of NASA"s Jet Propulsion Laboratory, California Institute of Technology, and the Ecole Normale Superieure to measure temperature, identifying warmer bright areas and cooler dark areas. On Jupiter, hotter areas indicate thin clouds, while colder areas indicate thick clouds, which block more heat from Jupiter"s core. The researchers tracked cloud and filament movements to calculate horizontal wind speeds.
This information enabled Siegelman and Klein to apply ocean and atmospheric science methods to Jupiter, calculating vertical wind speeds based on the derived temperatures and horizontal wind speeds. They found that Jupiter"s filaments behaved like Earth"s fronts.
The vertical wind speeds at the edges of fronts on Jupiter indicate that the fronts help transport energy as heat from the planet"s hot interior to its upper atmosphere, fueling the cyclones. Though convection is the primary driver, fronts contribute a quarter of the kinetic energy and forty percent of the vertical heat transport powering Jupiter"s cyclones.
"These cyclones on Jupiter"s poles have persisted since they were first observed in 2016," said Siegelman. "These filaments in between the large vortices are relatively small but they are an important mechanism for sustaining the cyclones. It"s fascinating that fronts and convection are present and influential on Earth and Jupiter - it suggests that these processes may also be present on other turbulent fluid bodies in the universe."
Siegelman also noted that Jupiter"s massive scale and Juno"s high-resolution imagery provide a clearer visualization of how smaller-scale phenomena like fronts connect to larger systems like cyclones, connections that are difficult to observe on Earth due to their smaller and more transient nature. However, a new satellite known as SWOT is expected to make observing these ocean phenomena easier.
"There is some cosmic beauty in finding out that these physical mechanisms on Earth exist on other far-away planets," said Siegelman.
Research Report:Frontogenesis at Jovian high latitudes
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