Jupiter's Great Red Spot is one of the solar system's most mysterious landmarks. Based on what scientists understand about fluid dynamics, this massive storm – which is big enough to engulf the Earth two or three times over – should have disappeared centuries ago.
This is Jupiter's Great Red Spot in 2000 as seen by NASA's Cassini orbiter.
Credit: NASA/JPL/Space Science Institute
Pedram Hassanzadeh, a postdoctoral fellow at Harvard University, and Philip Marcus, a professor of fluid dynamics at the University of California, Berkeley, think they can explain why. Their work, which Hassanzadeh will present at the annual meeting of the American Physical Society's Division of Fluid Dynamics in Pittsburgh on November 25, also provides insight into persistent ocean eddies and vortices that contribute to star and planet formation.
"Based on current theories, the Great Red Spot should have disappeared after several decades. Instead, it has been there for hundreds of years," said Hassanzadeh, who is a post-doctoral fellow at Harvard's Center for the Environment and the Department of Earth and Planetary Sciences.
Many processes dissipate vortices like the Red Spot, Hassanzadeh explained. The turbulence and waves in and around the Red Spot sap the energy of its winds. The vortex also loses energy by radiating heat. Finally, the Red Spot sits between two strong jet streams that flow in opposite directions and may slow down its spinning.
Some researchers argue that the Red Spot gains energy by absorbing smaller vortices. "Some computer models show that large vortices would live longer if they merge with smaller vortices, but this does not happen often enough to explain the Red Spot's longevity," Marcus said.
To probe the mystery of the Red Spot's survival, Hassanzadeh and Marcus built a model of their own. It differed from existing models because it was fully three dimensional and had very high resolution. Many vortex models focus on the swirling horizontal winds, where most of the energy resides. Vortices also have vertical flows, but these have much less energy.
"In the past, researchers either ignored the vertical flow because they thought it was not important, or they used simpler equations because it was so difficult to model," Hassanzadeh said.
Yet the vertical motion turns out to hold the key to the Red Spot's persistence. As the vortex loses energy, the vertical flow transports hot gases from above and cold gases from below the vortex toward its center, restoring part of its lost energy.
The model also predicts a radial flow, which sucks winds from the high-speed jet streams toward the vortex center. This pumps energy into the vortex, enabling it to last longer.
According to Hassanzadeh, the same vertical flow could explain why oceanic vortices, such as those formed near the Straits of Gibraltar, can last for years in the Atlantic Ocean. Their vertical flow plays a role in the ocean ecosystem by lifting nutrients to the surface.
Vortices may also midwife the formation of stars and planets, lasting for millions of years as they pull interstellar dust and rocks into large masses.
Hassanzadeh and Marcus know their model does not entirely explain the Red Spot's long life span. They believe the occasional absorption of smaller vortices, consistent with observation, may provide the extra energy needed for hundreds of years of life. They have begun modifying their computer model to test this thesis.
Perhaps, one day, Jupiter's Great Red Spot will seem a little less mysterious.
The presentation "On the Unexpected Longevity of the Great Red Spot, Oceanic Eddies, and other Baroclinic Vortices," is at 3:48 p.m. on Monday, November 25, 2013 in the David L. Lawrence Convention Center, Room 403. ABSTRACT: http://meeting.aps.org/Meeting/DFD13/Event/203662
The 66th Annual Division of Fluid Dynamics Meeting will be held at David L. Lawrence Convention Center in Pittsburgh, Pennsylvania from November 24-26, 2013. More meeting information: http://www.apsdfd2013.pitt.edu
REGISTERING AS PRESS
Any credentialed journalist, full-time or freelance, may attend the conference free of charge. Please email: firstname.lastname@example.org and include "DFD Press" in the subject line. Work space will be provided on-site during the meeting and news and graphics will be hosted on the Virtual Press Room: http://www.aps.org/units/dfd/pressroom/press.cfm
ABOUT THE APS DIVISION OF FLUID DYNAMICS
The Division of Fluid Dynamics of the American Physical Society (APS) exists for the advancement and diffusion of knowledge of the physics of fluids with special emphasis on the dynamical theories of the liquid, plastic and gaseous states of matter under all conditions of temperature and pressure. DFD Website: http://www.aps.org/units/dfd/index.cfm
Jason Socrates Bardi | EurekAlert!
Tangled magnetic fields power cosmic particle accelerators
14.12.2018 | DOE/SLAC National Accelerator Laboratory
In search of missing worlds, Hubble finds a fast evaporating exoplanet
14.12.2018 | NASA/Goddard Space Flight Center
The more objects we make "smart," from watches to entire buildings, the greater the need for these devices to store and retrieve massive amounts of data quickly without consuming too much power.
Millions of new memory cells could be part of a computer chip and provide that speed and energy savings, thanks to the discovery of a previously unobserved...
What if, instead of turning up the thermostat, you could warm up with high-tech, flexible patches sewn into your clothes - while significantly reducing your...
A widely used diabetes medication combined with an antihypertensive drug specifically inhibits tumor growth – this was discovered by researchers from the University of Basel’s Biozentrum two years ago. In a follow-up study, recently published in “Cell Reports”, the scientists report that this drug cocktail induces cancer cell death by switching off their energy supply.
The widely used anti-diabetes drug metformin not only reduces blood sugar but also has an anti-cancer effect. However, the metformin dose commonly used in the...
A research team from the University of Zurich has developed a new drone that can retract its propeller arms in flight and make itself small to fit through narrow gaps and holes. This is particularly useful when searching for victims of natural disasters.
Inspecting a damaged building after an earthquake or during a fire is exactly the kind of job that human rescuers would like drones to do for them. A flying...
Over the last decade, there has been much excitement about the discovery, recognised by the Nobel Prize in Physics only two years ago, that there are two types...
12.12.2018 | Event News
10.12.2018 | Event News
06.12.2018 | Event News
14.12.2018 | Power and Electrical Engineering
14.12.2018 | Physics and Astronomy
14.12.2018 | Physics and Astronomy