It’s difficult enough to track the weather on Earth, but with new thermal images of Jupiter’s Great Red Spot, scientists now have the first detailed interior weather map of a giant storm system on another planet. “This is our first detailed look inside the biggest storm of the solar system,” said Glenn Orton, a senior research scientist at NASA’s Jet Propulsion Laboratory. “We once thought the Great Red Spot was a plain old oval without much structure, but these new results show that it is, in fact, extremely complicated.”
The Great Red Spot is a cold region averaging about 110 Kelvin (minus 260 degrees Fahrenheit), and is so wide about three Earths could fit inside its boundaries. The new observations provide never-seen-before details, showing swirls of warmer air amid cooler regions. The reddest color of the Great Red Spot corresponds to a warm core within the otherwise cold storm system, and images show dark lanes at the edge of the storm where gases are descending into the deeper regions of the planet.
The thermal images obtained by giant 8-meter (26-foot) telescopes used for this study — the European Southern Observatory’s Very Large Telescope in Chile, the Gemini Observatory telescope in Chile and the National Astronomical Observatory of Japan’s Subaru telescope in Hawaii — have provided an unprecedented level of resolution and extended the coverage provided by NASA’s Galileo spacecraft in the late 1990s. Together with observations of the deep cloud structure by the 3-meter (10-foot) NASA Infrared Telescope Facility in Hawaii, the level of thermal detail observed from these giant observatories is comparable to visible-light images from NASA’s Hubble Space Telescope for the first time.
One of the most intriguing findings shows the most intense orange-red central part of the spot is about 3 to 4 Kelvin (5 to 7 degrees Fahrenheit) warmer than the environment around it, said Leigh Fletcher, the lead author of a paper published in the journal Icarus. While this temperature differential might not seem like a lot, it is enough to allow the storm circulation, usually counter-clockwise, to shift to a weak clockwise circulation in the very middle of the storm. Not only that, but on other parts of Jupiter, the temperature change is enough to alter wind velocities and affect cloud patterns in the belts and zones.
“This is the first time we can say that there’s an intimate link between environmental conditions — temperature, winds, pressure and composition – and the actual color of the Great Red Spot,” Fletcher said. “Although we can speculate, we still don’t know for sure which chemicals or processes are causing that deep red color, but we do know now that it is related to changes in the environmental conditions right in the heart of the storm.”
Unlocking the secrets of Jupiter’s giant storm systems will be one of the targets for infrared spacecraft observations from future missions including NASA’s Juno mission.