At the 72nd Annual Meeting of the APS Division of Fluid Dynamics, held in recent days in Seattle, Philip Marcus of the University of California, Berkeley, presented a study on Jupiter’s Great Red Spot. According to recent research, it’s shrinking but according to this new study based on photos and computer simulations that’s actually an impression due to clouds covering a part of it.

Philip Marcus and other researchers used observations of the Great Red Spot carried out during May and June 2019 of which the image (Courtesy Chris Go. All rights reserved) shows some examples. During that time it seemed that the clouds above the Spot were flaking and this was considered further evidence of that great storm’s shrinking. Instead, according to this new study, this concerns only the clouds above the Spot without affecting its size.

Images of the Great Red Spot were examined and computer simulations based on fluid physics were performed to reproduce the movements of clouds, cyclones and vortices in that area. Philip Marcus and his colleagues are convinced that they’re seeing normal phenomena of cloud flaking where clouds appear red due to exposure to the Sun’s emissions suffered over the storm. According to the researchers, these are natural phenomena due to the clash with the cyclones that creates stagnation points where the velocity abruptly and then restarts to move in different directions. These points indicate where an approaching cloud shattered and created the flakes that were observed. Under those clouds, the Spot may not have shrunk.

A secondary circulation, guided by heating and cooling above and below the vortex, could allow the Great Red Spot to keep on existing for centuries, fighting the decay of its energy due to the loss of viscosity, turbulence and heat. In May and June 2019 small vortices were created the northeast of the Spot and subsequently some of them merged with the storm, a phenomenon that doesn’t imply that it’s disappearing.

Commenting on the Great Red Spot’s future, Philip Marcus made a comparison by quoting writer Mark Twain who, after learning of the wrong publication of his obituary, stated that the report of his demise was greatly exaggerated. More studies will surely follow to better understand what’s happening to what is technically an anticyclone.

NASA’s Juno space probe, which is studying Jupiter from its orbit, can carry out detections under its surface and on July 11, 2017 already completed a flyby that allowed it to study the Great Red Spot. In the future it could collect more data on one of the planet’s most characteristic features to understand its actual future.