Clouds hide the true size and nature of Jupiter’s most distinctive feature, the Great Red Spot, according to a study led by University of California, Berkeley’s Professor Philip Marcus.
A series of false-color images capturing the repeated flaking of red clouds from the Great Red Spot in the Spring of 2019. In the earliest image, the flaking is predominant on the east side of the giant red vortex. The flake then breaks off from the Great Red Spot, but a new flake starts to detach in the fifth image. Image credit: Chris Go.
The Great Red Spot is one of the most recognizable features in Jupiter’s atmosphere and the entire Solar System.
Measuring in at 10,000 miles (16,000 km) in width, this prominent feature is 1.3 times as wide as Earth. Its reddish color is likely a product of chemicals being broken apart by solar UV light in the gas giant’s upper atmosphere.
The storm boasts wind speeds as high as 300 mph (500 kmh) and is powerful enough to tear apart smaller storms that get drawn into it.
It has been monitored since 1830 and has possibly existed for more than 350 years. In modern times, it has appeared to be shrinking.
“In the spring of 2019, observers photographed large red ‘flakes’ being ripped from the familiar red spot,” Professor Marcus said.
“But the flaking phenomena are a very natural state of a vortex with cloud coverage and not an indication of the Great Red Spot’s death. I don’t think its fortunes were ever bad.”
By analyzing the new images of the Great Red Spot with computer models that incorporate the physics of how fluids move, Professor Marcus and colleagues were able to determine the area of the spot.
They discovered that the area is larger than its underlying vortex, the swirling gas that defines it.
“Smaller cloud formation sometimes creates stagnation points, where the velocity abruptly stops, restarts and goes off in different directions,” they explained.
These points indicate where an approaching cloud shattered and created the flakes that were observed by astronomers.
“The loss of undigested clouds from the Great Red Spot through encounters with stagnation points does not signify the demise of the storm,” Professor Marcus said.
“The proximity of the stagnation points to the Great Red Spot during May and June does not signify its demise.”
“The creation of little vortices to the east, northeast of the Great Red Spot during the spring of 2019 and their subsequent merging with the storm with some does not signify its demise.”
“A secondary circulation, driven by the heating and cooling above and below the vortex, allows the Great Red Spot to continue to exist over the centuries, fighting off decay of its energy from viscosity, turbulence and heat loss,” he added.
The scientists presented their results November 25, 2019 at the 72nd Annual Meeting of the APS Division of Fluid Dynamics in Seattle, Washington.
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Philip Marcus et al. 2019. The Shedding of Jupiter’s Red Flakes Does Not Mean It Is Dying. 72nd Annual Meeting of the APS Division of Fluid Dynamics, abstract # L13.00001
