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Jupiter’s Great Red Spot has been around for longer, but Saturn’s periodic storms are far larger.
On Earth, hurricanes can span hundreds of kilometers, wreaking devastation whenever landfall occurs.
In 2007, Hurricane Felix became one of the most powerful category 5 hurricanes ever measured on Earth, reaching sustained wind speeds of 165 miles per hour (265 kph) and with gusts that achieved even greater speeds. But other planets consist of storms that are larger than the entirety of planet Earth. (NASA)
But on the Solar System’s giant planets, storms can far surpass anything seen throughout Earth’s history.
This assigned-color image of Saturn’s north pole highlights the hexagonal region and the central hurricane located within it. The hurricane itself is nearly 2,000 kilometers wide. (NASA/JPL-CALTECH/SSI)
Atop Saturn’s north pole lies a hurricane centered inside a hexagonal-shaped vortex.
A false-color animation of Saturn’s hexagon from about 70 individual frames stitched together. This polar vortex is approximately 11 times larger than the central hurricane located directly over the pole, and approximately double the diameter of planet Earth. (NASA/JPL-CALTECH/SSI/HAMPTON UNIVERSITY)
The hurricane’s winds reach 320 miles-per-hour (500 kph), spanning 2,000 km across.
This image of Jupiter, taken from Cassini in 2000 on its journey to Saturn, showcases just how much larger the Great Red Spot is compared to planet Earth, which is shown from the iconic 1972 image taken aboard the Apollo 17 mission. (NASA / BRIAN0918 AT ENGLISH WIKIPEDIA)
Jupiter’s Great Red Spot, known for nearly four centuries, could fit between 2-to-3 Earths inside of it, with winds exceeding 267 miles-per-hour (430 kph).
In December of 2010, a tiny, faint feature could just barely be seen in Cassini imaging data when a particular location in Saturn’s atmosphere crossed the day/night boundary. (NASA / JPL-CALTECH / SPACE SCIENCE INSTITUTE)
But from December of 2010 to August of 2011, the largest storm of all occurred: on Saturn.
From December of 2010 to August/September of 2011, the greatest storm ever witnessed in the Solar System raged on Saturn. It was not triggered by an asteroid strike or any identifiable external event. (NASA / JPL-CALTECH / SPACE SCIENCE INSTITUTE)
For 200+ days, this Saturnian hurricane raged, maintaining its leading “head” until May.
This infrared image of Saturn, taken by Cassini in 2011 and shown here in assigned color, helped astronomers identify the presence or absence of various elements and compounds. The whitish-blue color highlights the presence of methane while the reddish color indicates it absence. Note how, as the storm rages across the Saturnian world, it displays a notable lack of methane, particularly in the tail end. (NASA / JPL-CALTECH / SPACE SCIENCE INSTITUTE)
It came to encircle the entire planet, as methane-poor tail end stands out against the relatively methane-rich remainder.
February 23/24, 2011, comparison images of the same storm on Saturn. Images were taken 11 hours (1 Saturn-day) apart, at a resolution of 64 miles-per-pixel. (NASA / JPL-CALTECH / SPACE SCIENCE INSTITUTE)
Viewed 11 hours (1 Saturn-day) apart, we determined the hurricane migrated across Saturn at 60 miles-per-hour (100 kph).
These two assigned-color mosaics (middle and lower panels) were taken 11 hours apart by NASA’s Cassini spacecraft on February 26, 2011. White and yellow colors at the storm head are towering anvils of thunderstorm clouds created by strong convection from deeper within the atmosphere. At the anticyclonic vortex, the red color denotes deep clouds. The blue oval on the far right of the mosaic is a cold spot in the stratosphere. Note the slight westward drift of the storm complex over the span of 11 hours, corresponding to its inferred migration speed. (NASA/JPL-CALTECH/SPACE SCIENCE INSTITUTE)
These storms have occurred every 20–30 years since first observed in 1876, as hot air rises, cools and falls.
Saturn’s 2011 storm was captured from ground-based telescopes in a variety of visible and infrared wavelengths, with each view providing unique information about the color, temperature, and molecular composition of the storm. (ESO/UNIV. OF OXFORD/T. BARRY)
2011’s was the largest of all, large enough to contain ten-to-twelve Earths, but may be surpassed next time: in the 2030s.
One of the most spectacular mosaic images of Saturn taken by Cassini, this 2016 view shows the north pole, the rings, the planet’s shadow, and the nearly-fully illuminated face of our Solar System’s most visibly-ringed world. Note how quiet Saturn is most of the time; at some point during the 2030s, a new storm is expected to awaken. Unfortunately, the Cassini mission ended, and won’t be there to observe it. (NASA/JPL/SPACE SCIENCE INSTITUTE)
Mostly Mute Monday tells an astronomical story in images, visuals, and no more than 200 words. Talk less; smile more.
