NASA’s Voyager 1 views Jupiter’s Great Red Spot. Credit: NASA’s Goddard Space Flight Center.
The massive storm near the gas giant’s equator is receding, but collisions with a series of anticyclones are likely only superficial.
The stormy, age-old maelstrom of JupiterThe Great Red Spot was shaken but not destroyed by a series of anti-cyclones that collided with it in recent years.
The smaller storms cause chunks of red clouds to peel off, making the larger storm smaller in the process. But the new study found that these distortions are “superficial.” They are visible to us, but they are only skin deep on the red spot and do not affect the full depth.
The new study is published in the Journal of Geophysical Research: Planets, AGU’s journal for research into the formation and evolution of the planets, moons and objects of our solar system and beyond.
“The intense vorticity of the [Great Red Spot], along with its greater size and depth compared to the interacting eddies, guarantees its longevity, ”said Agustín Sánchez-Lavega, a professor of applied physics at Basque Country University in Bilbao, Spain, and lead author of the new paper. While the larger storm absorbs these smaller storms, “it gains energy at the expense of their rotational energy.”
A flake of red shells removed from Jupiter’s Great Red Spot during an encounter with a smaller anticyclone, as seen by the Juno spacecraft’s high-resolution JunoCam on Feb. 12, 2019. Although the collisions appear violent, planetary scientists believe it mainly surface effects, such as the crust on a crème brûlée. Credit: AGU / Journal of Geophysical Research: Planets
The Red Spot has been shrinking over the past 150 years, from a length of about 40,000 kilometers (24,850 miles) in 1879 to about 15,000 kilometers (9,320 miles) today, and researchers are still unsure about the causes of the decline, or even how the place was formed in the first place. The new findings show that the small anti-cyclones could help maintain the Great Red Spot.
Timothy Dowling, a professor of physics and astronomy at the University of Louisville and an expert on planetary atmospheric dynamics who is not involved in the new study, said “it is an exciting time for the Red Spot.”
Stormy collisions
Before 2019, the larger storm was hit by only a few countercyclones per year, while it was recently hit by as many as two dozen per year. “It’s really being ravaged. It caused a lot of alarm,” Dowling said.
Sánchez-Lavega and his colleagues wondered if these relatively smaller storms had disrupted their big brother’s spin.
The gas giant’s iconic feature is near the equator, compromising Earth concepts of a major severe storm for at least 150 years since the first confirmed sighting, although sightings in 1665 may have been of the same storm. The Great Red Spot is about twice the diameter of the Earth and blows around its circumference at speeds of up to 540 kilometers per hour.
“The [Great Red Spot] is the archetype among the eddies in planetary atmospheres, “Sánchez-Lavega said, adding that the storm is one of his” favorite features in planetary atmospheres. “
Cyclones such as hurricanes or typhoons usually revolve around a center of low atmospheric pressure, rotating counterclockwise in the Northern Hemisphere and clockwise in the South both on Jupiter and Earth. Anti-cyclones spin in the opposite direction as cyclones, around a center of high atmospheric pressure. The Great Red Spot is itself an anti-cyclone, although it is six to seven times the size of the smaller anti-cyclones that have collided with it. But even these smaller storms on Jupiter are about half the size of Earth and about 10 times the size of Earth’s largest hurricanes.
Sánchez-Lavega and his colleagues looked at satellite images of the Great Red Spot from the past three years, taken from the Hubble Space Telescope, the Juno spacecraft orbiting Jupiter, and other photos taken by a network of amateur astronomers with telescopes.
Devourer of storms
The team found that the smaller anticyclones passed through the fast peripheral ring of the Great Red Spot before circling the red oval. The smaller storms are creating some chaos in an already dynamic situation, temporarily altering the Red Spot’s 90-day longitude fluctuation and “tearing the red clouds off the main oval and forming streamers,” Sánchez-Lavega said.
“This group has done an extraordinarily careful and thorough job,” said Dowling, adding that the flaking of red material we see resembles a crème brûlée effect, with a swirl visible on the surface for a few miles that does not appear much. impact on the 200 kilometers depth of the Great Red Spot.
The researchers still do not know what caused the Red Spot to shrink in recent decades. But these anti-cyclones could sustain the giant storm for now.
“The intake of [anticyclones] is not necessarily destructive; it can increase the rotational speed of the GRS, and perhaps keep it in a steady state over a longer period of time, ”said Sánchez-Lavega.
Reference: “Jupiter’s Great Red Spot: Strong Interactions With Incoming Anticyclones in 2019” by A. Sánchez-Lavega, A. Anguiano-Arteaga, P. Iñurrigarro, E. Garcia-Melendo, J. Legarreta, R. Hueso, JF Sanz- Requena, S. Pérez-Hoyos, I. Mendikoa, M. Soria, JF Rojas, M. Andrés-Carcasona, A. Prat-Gasull, I. Ordoñez-Extebarria, JH Rogers, C. Foster, S. Mizumoto, A. Casely, CJ Hansen, GS Orton, T. Momary, and G. Eichstädt, March 17, 2021.
DOI: 10.1029 / 2020JE006686