Jupiter’s Great Red Spot is heat source for its upper atmosphere
Trapped between two jet streams, the Great Red Spot is an anticyclone swirling around a center of high atmospheric pressure that makes it rotate in the opposite sense of hurricanes on Earth. Image Credit: NASA/JPL/Space Science Institute
A NASA-funded study published in the July 27 issue of the journal Nature suggests Jupiter’s Great Red Spot may be the heat source behind surprisingly high temperatures in the giant planet’s upper atmosphere. Temperatures in Jupiter’s upper atmosphere are similar to those found at Earth, despite the gas giant being more than five times farther away from the Sun.
Scientists at Boston University’s Center for Space Physics searched for the mystery heat source by mapping temperatures far above Jupiter’s cloud tops using observations from Earth. The team used data from the SpeX spectrometer at NASA’s Infrared Telescope Facility (IRTF) on Mauna Kea, Hawaii. By observing infrared light hundreds of miles above Jupiter, researchers found temperatures to be much higher in certain latitudes and longitudes in the planet’s southern hemisphere, where the spot is located.
Mauna Kea Observatory. Photo Credit: Astrojunta
“We could see almost immediately that our maximum temperatures at high altitudes were above the Great Red Spot far below—a weird coincidence or a major clue?” said Boston University’s James O’Donoghue, lead author of the study.
The study suggests the gigantic storm in the Great Red Spot produces two kinds of turbulent energy waves that collide and heat the upper atmosphere. Gravity waves are much like how a guitar string moves when plucked, while acoustic waves are compressions of the air (sound waves). Heating in the upper atmosphere 500 miles (800 kilometers) above the Great Red Spot is thought to be caused by a combination of these two wave types “crashing”, like ocean waves on a beach.
“The extremely high temperatures observed above the storm appear to be the ‘smoking gun’ of this energy transfer,” said O’Donoghue. “This tells us that planet-wide heating is a plausible explanation for the ‘energy crisis’, a problem in which upper-atmospheric temperatures are measured hundreds of degrees hotter than can be explained by sunlight alone.”
This effect has been observed here on Earth, above the Andes mountains, and may occur elsewhere in the outer Solar System, though it has not yet been directly observed. Researchers believe this phenomenon also occurs on giant exoplanets orbiting other stars.
The Great Red Spot was discovered in the 17th Century and has delighted and mystified observers ever since. The spot is 2–3 times as wide as Earth and is considered a “perpetual hurricane”, with winds as high as 400 miles (approximately 644 kilometers) per hour.
NASA’s Juno spacecraft, which arrived at Jupiter on July 4, will have many opportunities during its 20-month mission to observe the Great Red Spot and the turbulent region that surrounds it. Juno will use its microwave radiometer, which passively measures heat coming from within the planet, to see hundreds of miles downward into Jupiter’s atmosphere. This capability will enable the spacecraft to study the deep structure of the Great Red Spot, as well as Jupiter’s colorful cloud bands and other prominent features.
Jim Sharkey
Jim Sharkey is a lab assistant, writer and general science enthusiast who grew up in Enid, Oklahoma, the hometown of Skylab and Shuttle astronaut Owen K. Garriott. As a young Star Trek fan he participated in the letter-writing campaign which resulted in the space shuttle prototype being named Enterprise. While his academic studies have ranged from psychology and archaeology to biology, he has never lost his passion for space exploration. Jim began blogging about science, science fiction and futurism in 2004. Jim resides in the San Francisco Bay area and has attended NASA Socials for the Mars Science Laboratory Curiosity rover landing and the NASA LADEE lunar orbiter launch.
