Jupiter is the largest planet in the Solar System and the fifth planet from the Sun. This gas giant has beautiful banded clouds, thin dust rings, the famous Great Red Spot, and dozens of moons. Jupiter is also the oldest planet in the Solar System, having formed 4.6 billion years ago. Its distance from the Sun is an average of 484 million miles (779 million km). Jupiter is 86,900 miles (139,900 km) wide, or 11 times wider than Earth. A year on Jupiter lasts 11.86 Earth years. Jupiter has the shortest day in the Solar System, lasting only 10 hours. Jupiter is the fourth brightest object in the Earth’s sky after the Sun, the Moon, and Venus. There are enough planets the size of Earth to fit inside Jupiter.
Jupiter has virtually no surface. The planet is mostly a swirling mixture of gases, consisting of three layers. These gases are mostly hydrogen and helium. The bright bands on Jupiter’s outer surface are likely jets of sulfur- and phosphorus-containing gases rising from the planet’s warmer interior. Because the planet rotates so quickly, completing one rotation every less than 10 hours, its outer atmosphere is divided into long belts of brighter and darker material, much like an extreme version of Earth’s jet streams.
Deep inside Jupiter, the internal pressure is so great that electrons are squeezed out of hydrogen atoms. This creates a powerful electrically conducting metal that powers Jupiter’s enormous magnetic field, the second-largest in the solar system after the Sun. The planet may have a core of solid material or a thick, dense “soup” made mostly of partially dissolved iron and silicon that can reach temperatures of 90,000 degrees Fahrenheit (50,000 degrees Celsius).
Jupiter is known for its destructive storms. The Great Red Spot is a single storm that lasts for at least 300 years. Data from NASA’s Juno probe shows that it penetrates the planet’s atmosphere to a depth of 480 kilometers, which is about 40 times deeper than the Mariana Trench on Earth. The Great Red Spot has been shrinking in recent decades. It now measures about 23,300 kilometers in diameter, but it used to be thousands of kilometers wider. The Great Red Spot has even been observed to absorb other, smaller storms.
Jupiter’s Great Red Spot is actually a giant storm that has been active for hundreds of years. This photo of the Great Red Spot was taken by Voyager 1 in 1979. Corbis Historical
Humanity has launched numerous unmanned missions to explore Jupiter and its moons. The Pioneer 10 and Pioneer 11 spacecraft, launched in March 1972 and April 1973, were the first to fly by Jupiter, gathering information about its intense radiation belts and taking some of the first photographs. Then the Voyager 1 and 2 probes, which both left Earth in 1977 and reached Jupiter in 1979, collected stunning photographs and data about the giant planet. They revealed Jupiter’s dim, dust-covered ring system, volcanic activity on its moon Io, and a number of previously unknown moons.
NASA’s dedicated Jupiter mission, Galileo, entered orbit around the massive planet in December 1995. Galileo studied Io and Jupiter’s icy moon Europa in detail and released a probe that fell into Jupiter’s atmosphere. The agency’s latest dedicated Jupiter spacecraft, Juno, has been in orbit since July 2016. Juno flies over the planet’s polar regions every 53.5 days and has studied its powerful magnetic field and bright auroras, among other things.
In October 2024, NASA launched the Europa Clipper probe to study the icy moon Europa and its subsurface ocean, which many scientists believe could harbor life. The European Space Agency’s Jupiter Icy Moons Explorer (JUICE) mission, launched in 2023, will also explore Europa and Jupiter’s two other large moons, Ganymede and Callisto.
Ganymede is the largest moon in the entire solar system. NASA
Jupiter has 95 known moons, and thousands of other smaller objects orbit the giant planet. Ganymede is the largest moon in the solar system, larger than the planet Mercury.
Some of Jupiter’s other moons are also giant worlds. Callisto is covered in impressive craters and may contain a liquid ocean beneath its thick icy crust. Europa has a similar ice-ocean structure, but its frozen outer shell is much thinner. And brightly colored Io is the most volcanically active body in our solar system.
Astronomer and science popularizer Carl Sagan once speculated about the possibility of jellyfish-like organisms floating on helium in Jupiter’s atmosphere, but most researchers today don’t have much hope that living organisms could roam freely on the gas giant.
NASA believes that Jupiter’s moon Europa, with its icy shell surrounding a huge volume of liquid water, is one of the most likely places in the solar system to detect alien life. However, Europa’s surface may have giant ice spikes, which could make landing on the frozen world difficult.
Jupiter, one of the brightest objects in the night sky, has been known since ancient times, so it has many names in different cultures. The ancient Greeks called Jupiter Phaethon, meaning “blazing star.” The Babylonians called this giant planet Marduk, the patron deity of Babylon. Other ancient names for Jupiter include Brihaspati (Sanskrit), Zedek (Hebrew), Muxing (meaning “Tree Star” in Chinese), and Mushtari (Arabic).
Processed 2021 images from the Hubble Space Telescope and the Gemini North Observatory in Hawaii reveal details of Jupiter’s turbulent atmosphere at different wavelengths, helping scientists figure out what drives the formation of powerful storms on the gas giant.
Scientists processed images obtained in infrared, visible and ultraviolet ranges to conduct an interactive comparison of different types of clouds above the gas giant.
Jupiter in infrared, taken by the Gemini North telescope in Hawaii. Gemini International Observatory/NOIRLab/NSF/AURA, M.H. Wong (UC Berkeley), et al.
The planet’s changing appearance at different wavelengths gives astronomers new insights into the behavior of Jupiter’s atmosphere. Oddly enough, the Great Red Spot, a giant superstorm raging south of Jupiter’s equator, is very visible in visible and ultraviolet light, but virtually disappears into the background in infrared light.
Comparison of the three types of wavelengths also shows that the dark region representing the Great Red Spot in the infrared image is larger than the corresponding red oval in the visible image. This discrepancy is caused by each imaging method capturing different properties of the planet’s atmosphere, according to a statement from the US National Optical-Infrared Astronomy Research Laboratory (NOIRLab), which released the images on May 11, 2021.
Jupiter in visible, ultraviolet, and infrared wavelengths. Gemini International Observatory/NOIRLab/NSF/AURA/NASA/ESA, M.H. Wong and I. de Pater (University of California, Berkeley), et al.
While infrared observations show areas covered in thick clouds, visible and ultraviolet images highlight the location of so-called chromophores – molecules that absorb blue and ultraviolet light, giving the spot its characteristic red color.
On the other hand, Jupiter’s counter-rotating cloud bands are clearly visible in all three images.
The images were taken simultaneously on January 11, 2017. The ultraviolet and visible images were taken by the Wide Field Camera 3 on the Hubble Space Telescope, and the infrared image was taken by the Near-Infrared Imager (NIRI) on the Gemini North orbiter in Hawaii.
In addition to the Great Red Spot, the Hubble images also show a smaller Red Spot called Junior, which formed in 2000 from the merger of three similar-sized storms to the southwest of a larger superstorm. Like the Great Red Spot, Junior is barely visible in infrared light, hidden within a larger band of cooler clouds.
This visible image of Jupiter from the Hubble Space Telescope shows various features of the planet’s atmosphere. NASA/ESA/NOIRLab/NSF/AURA/M.H. Wong and I. de Pater (University of California, Berkeley) et al.
In contrast to the red spots, the infrared image clearly shows a cyclonic vortex extending from east to west. This series of vortices, stretching for almost 72,000 kilometers (45,000 miles), appears as a bright band in the planet’s northern hemisphere.
In visible wavelengths, the cyclone appears dark brown, which is why it is called a “brown barge” in images taken by NASA’s Voyager spacecraft, which flew past the gas giant in 1979. However, in ultraviolet wavelengths, the object is barely visible under a layer of stratospheric haze that gets darker toward the north pole.
Scientist Mike Wong from the University of California compared the resulting images with radio signals recorded by NASA’s Juno spacecraft, which is currently studying the planet. These radio signals indicate lightning in Jupiter’s atmosphere. By combining the three types of images with lightning data, Wong and his team were able to examine different layers of cloud structure to better understand how powerful storms form on Jupiter.
Jupiter in ultraviolet light, imaged by the Hubble Space Telescope in January 2017. NASA/ESA/NOIRLab/NSF/AURA/M.H. Wong and I. de Pater (University of California, Berkeley) et al.
On July 12, 2022, the James Webb Space Telescope team released the first science-quality images from the mission, several astonishingly detailed images of the deep universe.
“When combined with the deep survey images released today, these Jupiter images provide a complete understanding of what Webb can see, from the faintest and most distant galaxies ever observed to the planets in our own cosmic backyard that you can see with the naked eye from your actual backyard,” said Brian Holler, a scientist at the Space Telescope Science Institute in Baltimore who helped plan the Jupiter observations, in a statement.
Jupiter and one of its many moons, Europa, are seen through the 2.12 µm filter of the James Webb Space Telescope’s NIRCam instrument. NASA, ESA, CSA, and B. Holler and J. Stansberry (STScI)
The photographs of Jupiter were taken during the Webb observatory’s commissioning, when mission members were calibrating and checking out the observatory’s four science instruments and other systems.
The Webb spacecraft, launched on December 25, 2021, was designed to probe deep into the universe’s past and study the first stars and galaxies. But the infrared observatory is a highly capable, multi-purpose instrument, and astronomers will use it to study a variety of cosmic objects and phenomena, including some in our own solar system, as the Jupiter images show.
The images are incredibly detailed, capturing the giant planet’s cloud bands, its famous Great Red Spot, and even some of its faint rings. Several moons are also visible, including Europa, a frigid world with a vast ocean beneath its icy shell.
Left: Jupiter and its moons Europa, Thebe, and Metis as seen through the James Webb Space Telescope’s 2.12-micron NIRCam filter. Right: Jupiter and Europa, Thebe, and Metis as seen through the 3.23-micron NIRCam filter. NASA, ESA, CSA, and B. Holler and J. Stansberry (STScI)
“I couldn’t believe we saw it so clearly and how bright it was,” said Stephanie Milam, Webb’s deputy for planetary science at NASA’s Goddard Space Flight Center in Greenbelt, Maryland, in the same statement. “It’s really exciting to think about the possibilities and opportunities we have to see objects like this in our solar system.”
The Webb team also observed several asteroids during the telescope’s commissioning, testing its ability to study fast-moving objects. Webb passed these tests with flying colors, according to the team.
Jupiter and some of its moons are seen through the James Webb Space Telescope’s 3.23 µm NIRCam filter. NASA, ESA, CSA, and B. Holler and J. Stansberry (STScI)
NASA’s Juno mission captures Jupiter’s colorful, chaotic clouds. During its 61st close flyby of Jupiter on May 12, 2024, NASA’s Juno spacecraft captured this color-enhanced image of the giant planet’s northern hemisphere. The image shows chaotic clouds and cyclonic storms in a region known to scientists as the folded-filamentary region. In these regions, the zonal jet streams that create the familiar banded patterns in Jupiter’s clouds break up, resulting in turbulent flows and cloud structures that change rapidly over just a few days.
Citizen scientist Gary Eason created this image using raw data from the JunoCam instrument, applying digital processing techniques to improve color and clarity.
Image data: NASA/JPL-Caltech/SwRI/MSSS. Image processing: Gary Eason © CC BY
When the raw image was taken, the Juno spacecraft was about 18,000 miles (29,000 kilometers) above Jupiter’s cloud tops, at a latitude of about 68 degrees north of the equator.
Raw JunoCam images are available for viewing and processing as image products at https://missionjuno.swri.edu/junocam/processing
For years, astronomers believed that Jupiter’s upper cloud layers, responsible for its famous pale brown belts, were made of frozen ammonia. But a new study by amateur and professional astronomers has found that these clouds are lower in the atmosphere than previously thought, and are made of something else entirely: most likely ammonium hydrosulfide mixed with smog.
Amateur astronomer Steve Hill was able to map Jupiter’s atmosphere using only special color filters and a telescope in his backyard. The results showed that the clouds are too deep in the planet’s warm atmosphere to be made of ammonia ice.
To investigate further, Hill teamed up with Patrick Irvine from the University of Oxford, whose research team had previously used the MUSE instrument on ESO’s Very Large Telescope (VLT) to analyse the atmospheres of gas giants.
MUSE is able to scan Jupiter’s atmosphere at different wavelengths, mapping the different molecules that make up the planet’s atmosphere. This animated image, based on real MUSE data, shows what the gas giant looks like at different wavelengths.
The new study shows that this new telescope approach can map the ammonia content of Jupiter’s atmosphere with astonishing accuracy. As for the clouds, the team found that Jupiter’s atmosphere is much like a layer cake. Clouds of ammonium hydrosulfide blanket the upper layers, but occasionally clouds of ammonia ice can be seen, lifted aloft by strong vertical convection. However, the full structure of the cloud layers is not yet fully understood, and collaboration between university scientists and amateur astronomers will be key to unraveling it.
Large hailstones made of ammonia could explain the gas’s absence from large regions of Jupiter’s atmosphere. The weather forecast for Jupiter now includes softball-sized hailstones known as “mushrooms” that form as severe thunderstorms rage through the planet’s turbulent atmosphere, according to a new study.
The results of the study confirm that these strange, ammonia-rich mushroom-shaped formations are also the source of Jupiter’s missing ammonia. The absence of this gas in some regions of Jupiter’s atmosphere has puzzled scientists for years.
Decades ago, astronomers noticed intense turbulence in the upper cloud layers of the gas giant in telescopic images. This discovery led scientists to conclude that Jupiter’s atmosphere was constantly churning and stirring, like boiling water in a saucepan.
But recent data from ground-based radio telescopes and NASA’s Juno spacecraft have revealed deep pockets of ammonia deficiency, reaching depths of 150 kilometers at all latitudes. This depletion is so severe in the planet’s atmosphere that no known mechanism can explain it.
A storm near Jupiter’s north pole, as captured by NASA’s Juno spacecraft. The ammonia-rich “mushrooms” that form in such storms help scientists build accurate weather models on many exoplanets. NASA
A new study, analyzing the aftermath of a powerful 2017 storm observed by Juno, strongly suggests that Jupiter’s raging storms are the key to solving this atmospheric mystery. The results also show that even localized storms can strip ammonia from the planet’s upper atmosphere and dump it to unexpectedly deep depths, suggesting that the long-held notion of a fully mixed atmosphere orbiting Jupiter is an illusion.
Because of the dense cloud cover that covers Jupiter, scientists can’t directly observe what lies beneath the planet’s churning cloud tops. Ammonia’s role is like a splash of color in a stream of water: it acts as a tracer, revealing otherwise invisible patterns and processes deep within Jupiter’s atmosphere.
To explain the lack of ammonia in Jupiter’s atmosphere, scientists in 2020 proposed a theory that severe storms on the planet create powerful updrafts that quickly lift ammonia-rich ice particles to high altitudes, where they combine with water ice to form a viscous liquid. Like hailstones on Earth, Jupiter’s mushroom-shaped features grow by accumulating layers of ice as storm currents repeatedly flow around them, eventually reaching the size of a soft marble and falling deep into Jupiter’s atmosphere, well below their point of origin. This process, theorized, led to the depletion of ammonia and water in the upper atmosphere, as observed by Juno and Earth-based telescopes.
A new study found that a distinct signature of radio signals transmitted by Juno confirmed that this unusual process was indeed happening. During its February 2017 flyby, the spacecraft flew over an active storm, and its instruments detected elevated concentrations of ammonia and water beneath the storm cloud.
The peculiar signal, which persisted even a month after the storm began, could only be explained by either a drop in temperature associated with melting ice, or an increase in ammonia concentrations, which could have occurred if ammonia was released from the mushroom balls as they melted.
The researchers suggest that Jupiter is unlikely to be unique in this regard, as gases such as ammonia are involved in planet formation and likely circulate in the atmospheres of hydrated gas giants both in our solar system and beyond.
New thunderstorms wider than Earth are spewing green lightning on Jupiter — and could cause one of the gas giant’s largest stripes to disappear. Two powerful thunderstorms have been spotted in Jupiter’s southern equatorial belt, likely producing powerful green lightning. Some experts believe the pale clouds could change the color of the rusty stripe and perhaps even cause it to “disappear.”
New photographs have captured two giant white thunderstorms raging in one of Jupiter’s large reddish-brown belts. The swirling storms, likely spewing giant green lightning through the gas giant’s cloudy atmosphere, could eventually weaken the belt’s rusty color, radically changing the planet’s appearance, experts say.
Astrophotographer Michael Carrer captured these stunning new images on November 30, 2024, using the Celestron 8-inch telescope near his home in Austria. The images show two large white spots located next to each other in the gas giant’s South Equatorial Belt (SEB), a vast dark band of clouds orbiting Jupiter.
Experts predict that two giant white thunderstorms (circled) could eventually dim the rusty brown color of Jupiter’s southern equatorial belt, making the region appear to vanish. Michael Carrer
“These white spots are giant thunderstorms,” John Rogers, an astronomer at the British Astronomical Association who specializes in Jupiter, told Spaceweather.com. “The last time we saw storms like this on Jupiter was eight years ago, in 2016-17.”
According to Spaceweather.com, the storms likely extend about 60 miles (100 kilometers) beneath Jupiter’s swirling surface, and while their exact width has not yet been calculated, both storms are “wide enough to swallow the Earth with room to spare.”
Rogers explained that these storms are not large enough to remain static for long periods of time, like Jupiter’s famous Great Red Spot, and will instead break apart. As they do, the ghostly hues of the storm will blend in with the rest of the rusty clouds of the SERB, “causing the familiar brown belt to fade as its color is diluted by the white storm front,” Spaceweather.com reports. If you look closely at the image, you can already see this beginning, as a few thin white trails appear behind the storms.
Researchers have already shown that lightning on Jupiter appears as bright flashes of green light. This image was taken by NASA’s Juno spacecraft on December 30, 2020. NASA/JPL-Caltech/SwRI/MSSS Image processing: Kevin M. Gill
This color change has happened before. In fact, according to Astronomy Magazine, SEBB-B was weakened by storms so much that it “disappeared” between 1973 and 1991, and briefly in 2010. However, it’s too early to say whether these new storms will destroy the current rust-colored belt.
Thunderstorms on Jupiter, like thunderstorms on Earth, are caused by convection, or mixing, within clouds and also produce lightning. However, unlike lightning on Earth, which is often blue due to water vapor, lightning on Jupiter is typically green due to ammonia in the atmosphere, according to NASA.
Jupiter just passed its closest point to Earth, known as “opposition,” becoming bright enough to be clearly visible to the naked eye and a great target for amateur astronomers and photographers like Carrère. The planet will reach its closest point to Earth on December 6, 2024, when Earth is directly between the solar system’s largest world and the sun.
Using the NASA/ESA/CSA James Webb Space Telescope, scientists have observed the region above Jupiter’s famous Great Red Spot, discovering a number of previously unobserved features. The region, previously thought to be unremarkable, is now teeming with complexity and activity. The findings were published in the journal Nature Astronomy in summer 2024.
Jupiter is one of the brightest objects in the night sky, and is easy to see on a clear night. With the exception of the bright northern and southern lights at the planet’s polar regions, the glow from Jupiter’s upper atmosphere is faint, making it difficult for ground-based telescopes to discern detail in this region. However, the infrared sensitivity of the Webb telescope allows scientists to study Jupiter’s upper atmosphere above the infamous Great Red Spot in unprecedented detail.
Jupiter’s upper atmosphere is the boundary between the planet’s magnetic field and the atmosphere below. It is home to the bright, intense northern and southern lights, which are produced by volcanic material ejected from Jupiter’s moon Io. However, closer to the equator, the structure of the planet’s upper atmosphere is affected by sunlight. Since Jupiter receives only 4% of the sunlight that Earth receives, astronomers have predicted that this region is homogeneous.
Jupiter’s atmosphere around the Great Red Spot (NIRCam and NIRSpec). European Space Agency
Jupiter’s Great Red Spot was observed by the Near Infrared Spectrograph (NIRSpec) on the Webb Space Telescope in July 2022 using the capabilities of the Integral Field Unit. The aim of the Early Release Science program was to find out whether the region was truly dim, and the region above the famous Great Red Spot was chosen for Webb observations. The team was surprised to find that the upper atmosphere contained many complex structures across the entire field of view, including dark arcs and bright spots.
“We thought, perhaps naively, that this region would be very boring,” said team leader Henrik Melin of the University of Leicester in the UK. “In fact, it’s as interesting as the northern lights, if not more so. Jupiter never ceases to amaze.”
Although the source of light in this region is sunlight, the team suggests that there must be another mechanism changing the shape and structure of the upper atmosphere.
“One way to change this structure is through gravity waves, like those that occur when a planet hits a beach and creates ripples in the sand,” Henrik explained. “These waves originate deep in the turbulent lower atmosphere, around the Great Red Spot, and can propagate upward, changing the structure and emissions in the upper atmosphere.”
Jupiter’s atmosphere around the Great Red Spot (NIRSpec image). European Space Agency
The team explains that these atmospheric waves can sometimes be observed on Earth, but are much weaker than those observed by Webb on Jupiter. They also hope to repeat Webb observations of these complex wave patterns in the future to study how they move through the planet’s upper atmosphere, and to increase our understanding of the energy balance of this region and how its characteristics change over time.
The Webb telescope is the largest and most powerful telescope ever launched into space. Under an international cooperation agreement, ESA provided the launch services for the telescope using an Ariane 5 launch vehicle. In collaboration with its partners, ESA was responsible for the development and qualification of the Ariane 5 modifications for the Webb mission and for the procurement of launch services by Arianespace. ESA also provided the NIRSpec spectrograph and 50% of the MIRI mid-infrared instrument, designed and built by a consortium of nationally funded European institutes (the MIRI European Consortium), in partnership with the Jet Propulsion Laboratory and the University of Arizona. Webb is an international partnership between NASA, ESA and the Canadian Space Agency (CSA).
The team’s August 2022 release from the James Webb Space Telescope features two highly detailed images of Jupiter, showing auroras around the poles. Both images are composites, meaning they combine multiple images from the telescope’s Near Infrared Camera (NIRCam), each using a different filter, into a single high-definition image.
The wide-angle image shows Jupiter’s dim rings, as well as two of its moons: Amalthea, the bright dot on the left, and Adrastea, the dim dot on the edge of the rings, located between Amalthea and Jupiter. Beyond the three bodies, dim points of light are thought to be galaxies.
“We honestly didn’t expect it to be this good,” said planetary scientist Imke de Pater, a professor emeritus at the University of California, Berkeley. De Pater led the observations of Jupiter with Thierry Foucher, a professor at the Paris Observatory, as part of Webb’s Early Science Release program. “It’s truly amazing that we can see details of Jupiter, including its rings, tiny moons, and even galaxies, in a single image,” she added.
Composite image of Jupiter taken by Webb’s NIRCam camera; the orange glow around the poles is the aurora borealis. NASA, ESA, CSA, Jupiter ERS Team; image processing by Judy Schmidt
The second image is a close-up of Jupiter, using three filters to capture details of its stormy atmosphere, including bright auroras.
“The brightness here indicates high altitude — which is why the Great Red Spot, like the equatorial region, has high-altitude haze,” said Heidi Hammel, a Webb interdisciplinary scientist for solar system observations and vice president of science at AURA. “The numerous bright white ‘spots’ and ‘bands’ likely represent very high cloud tops formed by condensed convective storms.”
You may be wondering why the colors in the images are not what we are used to seeing when it comes to Jupiter. Webb observes infrared light, not visible light, so the colors in both images do not match the colors we see with the naked eye. The infrared data has been superimposed on the visible light spectrum, so these images are “false” rather than “true.”
A composite image of Jupiter taken by Webb’s NIRCam camera, showing the planet’s rings and two of its moons, Amalthea and Adrastea. The blue glow around Jupiter’s poles is the aurora borealis. NASA, ESA, CSA, Jupiter ERS Team; image processing by Ricardo Hueso (UPV/EHU) and Judy Schmidt
And that brings us to an interesting point about how Webb actually works. When Webb “takes an image,” it doesn’t mean it takes a picture and beams it back to Earth — scientists get raw data that indicates the brightness measured by Webb’s sensors. So scientists have to process that data to create images.
Normally, that’s the job of the Space Telescope Science Institute (STScI), based in Baltimore. But in the case of this pair of Jupiter images, the data was processed by Judy Schmidt, a citizen scientist in Modesto, California. (To get the wide-angle image, she collaborated with Ricardo Hueso, a co-researcher at the University of the Basque Country in Spain.)
Schmidt and other amateur scientists often use publicly available data from space telescopes to process images. Schmidt processed her first Hubble image more than a decade ago. “I try to make the image look natural, even if it’s not close to what the eye sees,” Schmidt said.
These images are not just for their aesthetic appeal, of course. De Pater and Foucher’s research is designed to demonstrate Webb’s capabilities in studying the solar system, including imaging both bright and faint sources (in this case, Jupiter and its moons). The team will also study “Jupiter’s cloud layers, winds, composition, polar activity, and temperature structure,” and map the surfaces and atmospheres of Jupiter’s moons Io and Ganymede, according to the mission’s page.
The James Webb Space Telescope has captured bright auroras on Jupiter that have never been seen before. On December 25, 2023, scientists pointed the James Webb Space Telescope (JWST) at Jupiter and captured auroras at the gas giant’s north pole. Like the northern lights on Earth, Jupiter’s auroras occur when high-energy particles emitted by the Sun (the solar wind) reach the planet’s upper atmosphere and are directed toward the poles by its magnetic field. The study of Jupiter’s auroras was published on May 12, 2023, in the journal Nature Communications.
A composite image of Jupiter taken by the JWST’s NIRCam camera, showing the planet’s rings and two of its moons, Amalthea and Adrastea. The blue glow around Jupiter’s poles is the aurora borealis. NASA, ESA, CSA, ERS Jupiter Team; image processing by Ricardo Hueso (UPV/EHU) and Judy Schmidt
But Jupiter’s auroras form in a different way. Particles spewing from volcanoes on the gas giant’s hellish moon Io may go through the same process, according to the JWST team. Jupiter’s auroras have another key difference from our own: They glow hundreds of times brighter than Earth’s.
NASA’s James Webb Space Telescope previously captured images of Jupiter’s auroras in 2022, observing their glow at high altitudes near the gas giant’s poles. The images also showed faint rings around Jupiter and its two smaller moons, Amalthea and Adrastea.
These observations of Jupiter’s auroras, taken on 25 December 2023 with the Near Infrared Camera (NIRCam) on the JWST, have captured new details of the auroras on our solar system’s largest planet. NASA, ESA, CSA, Jonathan Nichols (University of Leicester), Mahdi Zamani (ESA/Webb)
Nichols and his fellow researchers plan to continue studying the phenomenon using the Hubble Space Telescope and the JWST to better understand how the suspected combination of particles might reach Jupiter’s atmosphere. The resulting data could reveal new details about Jupiter’s magnetosphere, the region of space around the planet that is influenced by its magnetic field.
These observations of Jupiter’s auroras, taken on December 25, 2023, by JWST’s Near Infrared Camera (NIRCam), reveal new details of the auroras on our solar system’s largest planet. The image on the right, originally released in 2023, shows Jupiter as the location of the observed auroras. NASA, ESA, CSA, STScI, Ricardo Hueso (UPV), Imke de Pater (UC Berkeley), Thierry Foucher (Paris Observatory), Lee Fletcher (University of Leicester), Michael H. Wong (UC Berkeley), Joseph DePasquale (STScI), Jonathan Nichols (University of Leicester), Mahdi Zamani (ESA/Webb)
Jupiter was twice as big as it is now – it could hold 2,000 Earths. This brings us closer to understanding how not only Jupiter but the entire solar system formed.
Long before Jupiter became the giant planet we see today, it was even bigger and had a much stronger magnetic field, according to a new study that looks back in time to see what the world was like in its early years.
New calculations, described in a paper published May 20, 2025, in the journal Nature Astronomy, show that just 3.8 million years after the first rocky objects in the solar system formed, Jupiter was twice its current size and had a magnetic field at least 50 times stronger than what we see today.
View of Jupiter. NASA/JPL/University of Arizona
To uncover Jupiter’s ancient planetary conditions, Batygin and his team largely bypassed the assumptions of existing planet-formation models, such as how quickly young planets accumulate primordial gas. Instead, they focused on two lesser-known moons of Jupiter: Amalthea and Thebe.
These small moons orbit very close to Jupiter and follow slightly tilted trajectories, which helped scientists track the past position of Io, Jupiter’s largest moon. This, in turn, helped the researchers determine the inner edge of Jupiter’s ancient circumplanetary disk, which played a key role in determining Jupiter’s past rotation speed. Using the law of conservation of angular momentum, the team reconstructed Jupiter’s original size.
Scientists’ calculations show that the radius of young Jupiter was almost twice that of today, and its volume would have been large enough to accommodate more than 2,000 Earth-sized planets. As the bloated magnetic giant radiated heat over time, it gradually cooled and contracted, shrinking in size. Today, Jupiter is still considered the “king of the planets”: its volume could accommodate 1,321 Earth-sized planets.
While the study does not directly examine how such a massive Jupiter might have influenced the early solar system, it does highlight that the planet’s formation and early evolution played a “key role” in shaping the overall architecture of the solar system.
Jupiter’s rings may be so tiny because of the planet’s massive moons. For years, scientists have wondered why Jupiter doesn’t have thick, bright rings like neighboring Saturn, and now they think they may know why.
While Jupiter has faint, hazy rings, as seen in recent images from the James Webb Space Telescope, they are nowhere near as prominent as those of Saturn or Uranus. In fact, they are so thin that they are impossible to see with standard astronomical equipment. But now, using sophisticated computer modeling, a team of scientists has found a possible explanation for why Jupiter’s rings aren’t as prominent as those of its neighbors: Jupiter’s moons may have prevented ice from forming around the massive planet. The team’s findings have been accepted for publication in The Planetary Science Journal in 2022.
“I’ve long been concerned about why Jupiter doesn’t have even more amazing rings that would outshine Saturn,” said Stephen Kane, an astrophysicist at the University of California, Riverside, who led the study. “If Jupiter had them, they would appear even brighter to us because it’s so much closer than Saturn.”
“We didn’t know these ephemeral rings existed until the Voyager spacecraft flew by because we couldn’t see them,” he added.
Kane wanted to find out why Jupiter’s rings are so dim, and whether the gas giant once had thicker rings but lost them. To explore these questions, he and his colleagues created a dynamical model that takes into account Jupiter’s orbit, as well as the orbits of the planet’s four main Galilean moons — Ganymede, Callisto, Io, and Europa.
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Saturn’s rings are made mostly of ice, some of which was deposited on the planet by comets, which are also made mostly of ice. If the moons orbiting the planet are massive enough, their gravity can cause ice to be ejected from the planet’s orbit. These massive moons can also alter the orbit of the ice enough to cause it to collide with them.
“We found that Jupiter’s Galilean moons, one of which is the largest moon in our solar system (Ganymede), would very quickly destroy any large rings that might form,” Kane said. “Massive planets form massive moons, which precludes the possibility of them forming large rings.”
The researchers’ modeling also led them to believe that it was unlikely that Jupiter ever had large rings in its history.
Ring systems around planets are not just beautiful; they can also be a useful tool for studying the planet’s history and possible collisions with moons or comets. This is because the composition of the ring material, its shape, and its size provide clues to the events that led to its formation.
The researchers now plan to use their models to study Uranus’ ring system. This research could shed light on how long Uranus’ rings will last and why it orbits the Sun differently than other planets in the Solar System. The ice giant orbits the Sun tilted on its side, and astronomers believe this unusual tilt is the result of a collision with another body. Uranus’ ring system could be the remnants of that collision.
“For us astronomers, it’s blood spatter on the walls of a crime scene,” Kane said. “When we look at the rings of the giant planets, we see evidence that some kind of catastrophe happened that put this material there.”
The mystery of Jupiter’s atmosphere sheds light on the solar system’s past. Jupiter’s atmosphere has a strange composition, but it could be explained if the planet formed farther from the sun than where it orbits today, according to a new study.
Since NASA’s Galileo mission in the 1990s, scientists have known that the atmosphere of the solar system’s largest planet contains heavier chemical elements, with more protons in the core, than the Sun’s atmosphere. That means Jupiter’s atmosphere also has a higher proportion of heavier elements than the material from which the planet formed about 4.5 billion years ago. For every atom of hydrogen in Jupiter’s atmosphere, there are more atoms of oxygen or carbon than in the Sun’s atmosphere.
The study was accepted for publication in the Astrophysical Journal in 2021 and suggests that this strange chemistry could be explained if the gas giant formed four times further from the Sun than where it currently orbits. Such an origin would not be all that surprising, as scientists know that planets often migrate during their formation. This movement is usually caused by gravitational interactions between the disk of material from which the planets form and the star itself.
Using computer simulations of planet formation, the study found that Jupiter, having formed so far from the Sun, would be the perfect size to attract many so-called planetesimals. These planetary embryos form in the same debris disks as planets, but later in the system’s formation.
Jupiter’s southern hemisphere, as seen by NASA’s Juno spacecraft. In a new study, NASA’s NuSTAR space telescope has captured the highest-energy light from Jupiter yet. Enhanced image by Kevin M. Gill (CC-BY) based on images courtesy of NASA/JPL-Caltech/SwRI/MSSS
To help understand distances in the solar system, scientists call the average distance from the Earth to the Sun one astronomical unit, or AU. One AU is about 93 million miles (150 million kilometers).
Late accretion is important. If planetesimals had collided with the nascent Jupiter too early, the heavier elements they contained would have accumulated closer to the planet’s interior, where they would have been invisible to the Galileo mission.
Even stranger, NASA’s current Juno mission to Jupiter has provided measurements of the planet’s gravity field, changes in the gravitational forces exerted by the planet, that also appear to be at odds with Galileo’s observations.
Scientists have found that structural models consistent with Jupiter’s gravity field as measured by Juno predict that the planet’s outer part should not actually contain many heavy elements. This is inconsistent with the gravity field, which predicts a large number of heavy elements. These heavy elements will only remain in the planet’s upper atmosphere after planetesimal impacts, since the entire planet is not mixed properly.
Juno has shown that Jupiter does not have complete convection, its matter is not completely mixed. It is therefore assumed that this outer region does not necessarily communicate with the deep interior.
This image, taken on Feb. 17, 2020, shows bright bands of haze particles enveloping the main clouds of Jupiter’s atmosphere vertically across the center of the image. The haze is a mystery: Scientists have not been able to determine its cause or composition, NASA said in a statement. One hypothesis is that jet stream bands surrounding the normal haze region may contribute to its formation. When Juno took the image, the spacecraft was about 15,610 miles (25,120 kilometers) above Jupiter’s cloud tops. NASA/JPL/SwRI/MSSS; image processing by Gerald Eichstedt
The second image, taken on April 10, 2020, offers a much closer look at the planet’s atmosphere, taken from an altitude of just 8,650 kilometers (5,375 miles). The image shows small clouds that scientists have dubbed “pop-ups” because they stand out brightly at the edges of atmospheric swirls, NASA said in a statement .
Jupiter as seen from Juno. NASA’s Juno spacecraft has been orbiting Jupiter since 2016, sending back stunning images of the solar system’s largest planet.
Using data from NASA’s Juno spacecraft, an amateur scientist created this photograph of a dimly lit Jupiter. NASA/JPL-Caltech/SwRI/MSSS/Roman Tkachenko), 2018
Amateur scientist Gerald Eichstadt processed this image of Jupiter’s south polar region, showing the distinctive cloud bands that envelop the gas giant. NASA/JPL-Caltech/SwRI/MSSS/Gerald Eichstadt, 2018
In this new image from NASA’s Juno spacecraft, a cyclone sweeps through Jupiter’s Northern Temperate Belt (NNTB). The NNTB is a prominent band that encircles the planet near its north pole. Hidden within the red-orange cloud band is a gray anticyclonic storm rotating counterclockwise, the opposite direction of the other gases in its vicinity. Juno captured this image during a close flyby of Jupiter on May 23, 2018, when the spacecraft was about 7,900 kilometers (4,900 miles) from the planet’s cloud tops. NASA/JPL-Caltech/SwRI/JunoCam, 2018
Jupiter and the Great Red Spot as seen by the Juno spacecraft. NASA’s Juno spacecraft captured this image of Jupiter on April 1, 2018. Citizen scientists Gerald Eichstedt and Sean Doran processed data from the JunoCam instrument to create this stunning image. NASA/JPL-Caltech/SwRI/MSSS/Gerald Eichstedt/Sean Doran, 2018
Juno Sees Jupiter’s Massive ‘Anticyclone’ Citizen scientists Gerald Eichstedt and Sean Doran created this image of a massive storm on Jupiter known as NN-LRS-1 using data acquired by NASA’s Juno spacecraft on July 10, 2017. NASA/JPL-Caltech/SwRI/MSSS/Gerald Eichstedt/Sean Doran, 2018
Jupiter’s Great Red Spot. Citizen scientists Gerald Eichstedt and Sean Doran processed this image of Jupiter’s Great Red Spot using data collected by NASA’s Juno spacecraft on April 1, 2018. Gerald Eichstedt/Sean Doran/NASA/JPL-Caltech/SwRI/MSSS, 2018
This enhanced color image of Jupiter’s Great Red Spot was created by citizen scientist Jason Major using data from the JunoCam camera on NASA’s Juno spacecraft. NASA/SwRI/MSSS/Jason Major, 2018
This enhanced color image of Jupiter’s Great Red Spot was created by citizen scientist Kevin Gill using data from the JunoCam camera on NASA’s Juno spacecraft. NASA/SwRI/MSSS/Kevin Gill, 2018
This true-color image shows how Jupiter’s Great Red Spot would appear to a viewer aboard NASA’s Juno orbiter. The image was created by citizen scientist Björn Jönsson using data from Juno’s JunoCam. NASA/JPL-Caltech/SwRI/MSSS/Björn Jönsson, 2018
Jupiter’s cloud bands. NASA’s Juno spacecraft captured this image of Jupiter’s cloud bands. Research suggests that the bands extend more than 1,000 miles (1,600 kilometers) into the planet. NASA/JPL-Caltech/SwRI/MSSS/Gerald Eichstedt/Sean Doran, 2018
NASA’s Juno spacecraft captured this image of Jupiter’s southern hemisphere during its ninth close flyby of the planet on Dec. 16, 2017. Juno scientists released the image on Feb. 7, 2018, as the spacecraft was completing its 10th flyby. The spacecraft captured this image from 30,970 kilometers (19,244 miles) above Jupiter’s cloud tops, and citizen scientist Gerald Eichstaedt processed raw data from the JunoCam camera to create this color-enhanced image. NASA/JPL-Caltech/SwRI/MSSS/Gerald Eichstaedt, 2018
The colorful cloud belts of Jupiter’s southern hemisphere dominate this image taken on January 12, 2018, by NASA’s Juno spacecraft orbiting the gas giant. Juno captured the image on December 16, 2017. Image processing was done by citizen scientist Kevin M. Gill. NASA/JPL-Caltech/SwRI/MSSS/Kevin M. Gill, 2018
Swirling clouds on Jupiter, as seen in this image taken by the JunoCam instrument on the Juno spacecraft and processed by amateur scientist Roman Tkachenko. Roman Tkachenko/NASA, 2018
Jupiter’s billowing clouds look like a work of art in this processed image from NASA’s Juno spacecraft. Citizen scientist Eric Jorgensen enhanced the colors in the original image to bring out details of Jupiter’s intricate cloud structure. Visible in the upper left is one of eight white oval storms known collectively as the “string of pearls.” NASA/JPL-Caltech/SwRI/MSSS/Eric Jorgensen, 2018
The Juno spacecraft flies above Jupiter’s clouds during its fifth flyby. NASA’s Juno spacecraft captured this enhanced color image of Jupiter during its fourth close flyby on Feb. 2, 2017. NASA/JPL-Caltech/SwRI/MSSS/Roman Tkachenko, 2018
One of Jupiter’s stormy “pearls” is the white oval on the left side of this new image taken by NASA’s Juno spacecraft on Dec. 11, 2016. It is the seventh of eight powerful storms that make up Jupiter’s “string of pearls,” according to NASA. NASA/JPL-Caltech/SwRI/MSSS, 2018
NASA’s Juno spacecraft was flying directly over Jupiter’s south pole when JunoCam captured this image on Feb. 2, 2017, from about 63,000 miles (101,000 kilometers) above the planet’s cloud tops. The image was processed by citizen scientist John Landino. This enhanced color version shows bright, high clouds and numerous twisting, oval thunderstorms. NASA/JPL-Caltech/SwRI/MSSS/John Landino, 2018
The image is based on raw data from the JunoCam camera on NASA’s Juno mission to Jupiter. “Tone and color correction… enhances depth and detail,” says the citizen scientist who created the image. NASA/JunoCam/Synthetrix, 2018
NASA’s Juno spacecraft captured this image of Jupiter’s north pole on Aug. 27 from a distance of 120,000 miles (195,000 kilometers). NASA/JPL-Caltech/SwRI/MSSS, 2018
This image of Jupiter’s north pole, taken by NASA’s Juno probe on Aug. 27, 2016, from a distance of 78,000 kilometers (47,000 miles), shows storms and weather systems unlike any other in the solar system. NASA/JPL-Caltech/SwRI/MSSS, 2018
This infrared image of Jupiter’s southern lights was taken by Juno on August 27, 2016. Images like this are impossible to obtain from Earth. NASA/JPL-Caltech/SwRI/ASI/INAF/JIRAM, 2018
NASA’s Juno spacecraft captured this image of Jupiter and its four large Galilean moons on June 21, 2016, at a distance of 6.8 million miles (10.9 million kilometers) from Jupiter. NASA/JPL-Caltech/SwRI/MSSS, 2018
This artist’s illustration shows NASA’s Juno spacecraft approaching Jupiter. NASA/JPL-Caltech, 2018
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