The Eye of Jupiter, or the Great Red Spot, is a gigantic storm on Jupiter’s surface. This raging centuries-old cyclone is bigger than Earth and has solar winds blowing up to 400 miles per hour (644 kilometers.) Compare that with the largest Earth hurricane stretching 1,000 miles; you’ll get a small inkling of the Eye of Jupiter’s enormity.
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What Is Jupiter’s Eye?
Understanding Jupiter’s Eye means understanding Jupiter’s makeup. This storming planet is a literal gas giant at a thousand times Earth’s size. Its atmosphere primarily contains helium and hydrogen; a liquid hydrogen ocean encircles its core.
Storms don’t dissipate as they make their way onto land, like here on Earth, because Jupiter has no solid ground. These conditions make the planet a giant storm factory, with Jupiter’s Eye being its best-known cyclone.
The Great Red Spot remains trapped between two jet streams. It is an anticyclone rotating around a high atmospheric center in the opposite direction of Earth’s hurricanes. NASA’s Galileo observed the Great Red Spot’s outer edges turning counterclockwise while the center weakly rotated clockwise.
Jupiter Eye Size
You may wonder how big Jupiter’s Eye is. First, let’s look at the planet itself. Jupiter is a gas giant with twice the mass of all the other planets combined. It’s enormous.
The Eye of Jupiter is currently about 1.3 times Earth’s size. That means our entire world fits inside this storm, and plenty of room remains.
Juno flyby data shows the storm’s “roots” extend about 200 miles into its atmosphere. By comparison, Earth hurricanes usually extend 9 miles from top to bottom.
The composite image below places Earth inside Jupiter’s Eye for comparison.
How Long Has the Great Red Spot Existed?
Astronomer Robert Hooke may have noted the Great Red Spot in May 1664, when he observed a small spot “in the biggest of the three obscurer belts of Jupiter.” Current scientists believe Hooke’s spot was in the North Equatorial Belt, but the Eye of Jupiter resides in the South Equatorial Belt.
Giovanni Cassini likely spotted the Eye of Jupiter in the Spring and Fall of 1665 when he documented 13 observations between August and October. The next known observation of the red spot occurred by Samuel Schwabe. In 1878, C.W. Pritchett observed the massive storm.
Since then, records of at least one yearly telescope observation of the Great Red Spot have existed.
How Long Will the Eye of Jupiter Last?
Not only do scientists not know precisely how long the Eye of Jupiter has existed, but they also hope to discover how long the storm may continue raging. While astronomers documented changes to the enormous storms over time, more information came in the past few decades. Images from probes, flybys, and missions help astronomers understand the Great Red Spot’s changes.
Voyager and Galileo’s images showed a dark area around the storm, meaning not many clouds existed. More recent photos, like the ones from the Webb Telescope, however, show bright white cloud regions, indicating a general brightening of the planet’s cloud features.
While at one time the storm could encompass three Earths, today, it continues shrinking. Oddly, it is growing taller during the overall shrinking process over the past 150 years. It constantly changes in shape and size.
Eye of Jupiter Shrinking and Getting Taller at the Same Time
The continual record since 1878 proves the vast storm is shrinking. Scientists thought the internal winds would grow stronger as the storm shrunk. They equate it to an ice skater spinning faster as they pull in their arms.
Instead of more vigorous and faster spinning, the winds stretch the storm “up” into the atmosphere. The analogy for this occurrence is clay on a potter’s wheel. The clay elongates into a tall vase shape by pushing the lump inward while it spins. The same happens with the Great Red Spot: it moves upward as it rotates.
A Goddard Space Flight Center team of experts in planetary atmospheres studies the Eye of Jupiter to understand Earth’s weather better. Scientists Amy Simon, Mark Loeffler, and Reggie Hudson perform laboratory studies to learn the chemical makeup and causes of the spot’s coloring.
Since 2014, the storm’s color has deepened and become more orange. The team thinks the chemicals which change the color get carried higher into the atmosphere as the storm elongates. Higher altitudes mean more UV radiation and intensified color.
Goddard scientists create ammonium hydrosulfide in a laboratory and blast it with charged particles to simulate how the cosmic rays impact Jupiter’s clouds. Understanding the colors within the Eye of Jupiter solves part of its mystery since reflected light, on its own, doesn’t give up chemical composition secrets.
Designing lab experiments similar to Jupiter’s atmospheric conditions helps scientists better understand Jupiter’s storms and how long they might last. They are still determining if the storm will continue shrinking and breaking up or raging on a smaller scale.
Great Red Spot Image
The image below is a composite from the Webb Telescope in which you can see the Great Red Spot appearing white as it reflects sunlight. How does the Webb science team use infrared filters to capture the Eye of Jupiter and other space objects?
What Did James Webb Find on Jupiter?
The James Webb Space Telescope launched from the ESA spaceport in French Guiana in December 2021. Its Near-Infrared Camera (NIRCam) has three infrared filters. Unfortunately, human eyes can’t see infrared light, so scientists collaborate to translate the camera’s data into pictures.
Longer wavelengths look red, while shorter wavelengths appear blue to human eyes. The phenomenal NIRCam image below is a composite of several Webb photos.
Notice the auroras from a red filter that also captures reflected light from the lower clouds. A yellow and green filter shows a swirling haze at both poles.
Then a third blue filter reflects light from a deeper cloud. Finally, the show’s star (or storm?) is the Eye of Jupiter. The Great Red Spot and the center cloud band appear white because they reflect sunlight.
What Other Storms Rage on Jupiter?
Jupiter’s storm-pocked surface gives astronomers data for unlocking its mysteries. Beyond the Eye of Jupiter, both poles have enormous cycles that stay in geometric patterns. The north pole has eight cyclones circling a central cyclone. The south pole has five storms around one major pole hurricane.
Each polar storm’s size is approximately the distance from New York City to Naples, Italy. Their solar wind speeds reach 220 miles per hour (350 km/hour.) These winds are slower than those raging in Jupiter’s Eye but still greater than Earth’s highest Category 5 storms.
- Earth Category 5 wind speeds: 157 mph and greater
- Jupiter’s polar storm wind speeds: 220 mph
- Great Red Spot wind speeds: 400 mph
NASA’s Juno spacecraft took infrared images of Jupiter’s polar storms in February 2017. Then scientists combined them to represent radiant heat, as seen below.
- Thinner yellow clouds: 9℉ (-13℃)
- Thicker dark red clouds: -181℉ (-83℃)
While planetary scientists refer to the Eye of Jupiter as a centuries-old massive storm, they’re still determining the storm’s actual age. It has solar winds raging up to 400 miles per hour, and it is so huge that Earth could fit right down inside it.
Scientists have observed the growing and shrinking of the Great Red Spot over time. Planetary scientists are still determining if the Eye of Jupiter will continue shrinking until it disappears or if it will continue to storm for centuries to come.