New Juno Data Reveals Jupiter is Smaller and More ‘Squeezed’ Than Previously Thought

Posted on February 5, 2026 by Igor Mitreski

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Leveraging high-precision radio occultation measurements from NASA’s Juno mission, planetary scientists have significantly refined the shape of Jupiter. Their findings reveal that the planet’s polar, equatorial, and mean radii are smaller than earlier estimates from NASA’s Pioneer and Voyager missions, with substantially reduced uncertainty.

This vibrant visible-light image of Jupiter was captured using the Hubble Wide-Field Camera 3 on January 11, 2017. Featured prominently are the Great Red Spot and a long brown feature known as the “Brown Barge,” stretching approximately 72,000 km (around 45,000 miles) from east to west, with Red Spot Junior (Oval BA) on the lower right. Image credits: NASA / ESA / NOIRLab / NSF / AURA / Wong et al. / De Peyter et al. / M. Zamani.

“Jupiter, recognized as the largest planet in our solar system, is an almost oblate spheroid due to its rapid rotation of 9 hours, 55 minutes, and 29 seconds, causing a slight flattening at the poles and a bulge at the equator,” stated Dr. Eli Galanti of the Weizmann Institute of Science.

“This unique shape results from the gravitational forces pulling inward and centrifugal forces pushing outward from its rotation axis. Consequently, Jupiter’s equatorial radius is approximately 7% larger than its polar radius.”

“For celestial bodies with a uniform density, the shape is ideally ellipsoidal. However, Jupiter’s internal density varies significantly from the cloud layer of about 1 bar, where density is less than 1 kg/m³, to deeper layers reaching densities of several thousand kg/m³.”

“This density variation causes the planet’s shape to deviate from a simple ellipsoid by tens of kilometers, as reflected in fluctuations of the gravitational field across latitudes.”

“Additional alterations in Jupiter’s shape are induced by strong zonal winds detected at cloud level,” Dr. Galanti continued.

“These winds modify the centrifugal force, leading to variations of about 10 km mainly at lower latitudes.”

Historically, Jupiter’s dimensions were based on data from six radio occultation experiments conducted by NASA’s Pioneer and Voyager missions in the 1970s.

In this groundbreaking study, researchers reviewed radio occultation data collected during 13 close encounters between Juno and Jupiter, integrating the effects of zonal winds into their analysis.

“Radio occultation enables us to peer through Jupiter’s dense, opaque atmosphere to understand its internal structure,” the researchers elucidated.

“During the occultation experiment, Juno transmits radio signals to NASA’s Deep Space Network on Earth.”

“As these signals traverse Jupiter’s electrically charged ionosphere, they experience bending and delay.”

“By measuring the frequency changes caused by this bending, we can derive the temperature, pressure, and electron density at various atmospheric depths.”

The research concluded that Jupiter is approximately 8 km narrower at its equator and 24 km flatter at its poles.

“Including the effects of zonal winds significantly diminishes uncertainty in our understanding of Jupiter’s shape,” the researchers noted.

“At a pressure level of 1 atmosphere, we’ve determined a polar radius of 66,842 km, an equatorial radius of 71,488 km, and a mean radius of 69,886 km, which are smaller by 12 km, 4 km, and 8 km than previously estimated, respectively.”

For more details, view the findings published in this week’s Nature Astronomy.

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E. Galanti et al. Jupiter’s Size and Shape. Nat Astron published online on February 2, 2026. doi: 10.1038/s41550-026-02777-x

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Source: www.sci.news

Unlocking the Secrets of Jupiter and Saturn: How Polar Cyclones Expose Hidden Interiors

Posted on January 20, 2026 by Igor Mitreski

A groundbreaking study by planetary scientists at the Massachusetts Institute of Technology (MIT) reveals how the significant differences in polar vortex patterns between Jupiter and Saturn are influenced by the unique properties of their deep interiors. These findings offer valuable insights into the structure of these gas giants.

This composite image, captured by the JIRAM instrument aboard NASA’s Juno satellite, depicts a central low-pressure system at Jupiter’s north pole along with eight surrounding low-pressure systems. The colors in this image represent radiant heat, revealing temperature variations in their cloud layers. Image credit: NASA / JPL-Caltech / SwRI / ASI / INAF / JIRAM.

“Our study shows that the internal properties, including the softness of the vortex base, influence the fluid patterns observed at the surface,” explained Dr. Wang-Ying Kang from MIT.

The research was inspired by stunning images of Jupiter and Saturn obtained from NASA’s Juno and Cassini missions.

Since 2016, Juno has been orbiting Jupiter and revealing astonishing details about its north pole and intricate spiral formations.

The data suggest that each vortex on Jupiter is immense, measuring around 5,000 km (3,000 miles) in diameter.

Meanwhile, Cassini documented Saturn’s iconic polar vortex, which spans a singular hexagonal shape approximately 29,000 km (18,000 miles) wide, before its controlled descent into Saturn’s atmosphere in 2017.

“Despite their similarities in size and primary composition of hydrogen and helium, deciphering the differences in polar vortices between Jupiter and Saturn has been challenging,” noted MIT graduate student Jial Shi.

Researchers aimed to uncover the physical mechanisms behind the formation of either a single vortex or multiple vortices on these distant planets.

To achieve this, they employed a two-dimensional model of surface fluid dynamics.

While polar vortices are inherently three-dimensional, the fast rotation of Jupiter and Saturn leads to uniform motion along their rotational axes, allowing the team to effectively analyze vortex evolution in two dimensions.

“In rapidly rotating systems, fluid motion tends to be uniform along the axis,” Dr. Kang added. “This insight allowed us to convert a 3D challenge into a 2D problem, significantly speeding up simulations and reducing costs.”

With this in mind, researchers created a two-dimensional model of vortex behavior in gas giants, adapting equations that describe the evolution of swirling fluids over time.

“This equation is commonly used in various situations, including modeling cyclones on Earth,” Dr. Kang stated. “We tailored it for the polar regions of Jupiter and Saturn.”

Scientists applied the two-dimensional model to simulate fluid dynamics on gas giants in various scenarios, adjusting parameters such as planetary size, rotational speed, internal heating, and the characteristics of the fluid.

They introduced random “noise” to simulate initial chaotic fluid flow on the planets’ surfaces.

By analyzing how this fluid evolved over time across different scenarios, the researchers found that some conditions led to the formation of a single large polar vortex, akin to Saturn’s structure, while others resulted in multiple smaller vortices, similar to those on Jupiter.

Through careful examination of the parameters affecting each scenario, the study identified a unifying mechanism: the softness of the vortex base constrains the size that vortices can attain.

The softer and lighter the gas at the bottom of the vortex, the smaller the resulting vortex, enabling multiple smaller vortices to exist at Jupiter’s poles. Conversely, a denser and harder base permits the growth of sizable vortices, manifesting as a singular entity like Saturn.

If this mechanism holds for both gas giants, it could suggest that Jupiter has a softer internal composition, while Saturn may contain denser materials.

“The fluid patterns we observe on the surface of Jupiter and Saturn may provide insights into their interior compositions,” Shi remarked.

“This is crucial because Saturn’s interior likely harbors richer metals and more condensable materials, leading to stronger stratification than that found in Jupiter,” Shi added. “This will enhance our understanding of gas giant planets.”

The team’s findings will be published in the Proceedings of the National Academy of Sciences.

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Gial Sea & One In Can. 2026. Polar vortex dynamics of gas giant planets: Insights from 2D energy cascades. PNAS in press.

Source: www.sci.news

Jupiter: Smaller Than Anticipated and Facing Compression

Posted on September 12, 2025 by Igor Mitreski

Artistic representations of the Juno spacecraft above Jupiter’s Antarctic region

NASA/JPL-Caltech

Recent findings suggest Jupiter is not as large as previously believed, based on over four decades of radius measurements.

As a gas giant, Jupiter lacks a solid outer shell like Earth. Nevertheless, astronomers determine its shape by examining how the gas height varies around Earth at a consistent pressure level.

The most accurate measurements of this gas pressure level date back to NASA’s Voyager and Pioneer missions over 40 years ago. These spacecraft utilized radio waves to transmit signals through Jupiter’s atmosphere to Earth, allowing scientists to gather data and compute gas pressure at specific altitudes, employing a method known as radio occultation.

Currently, Eli Garanti from the Weizmann Institute of Science in Israel and his team have been measuring Jupiter’s radius since 2016, using radio occultation data obtained from NASA’s Juno spacecraft, which has been orbiting the gas giant since that year. They report that Jupiter’s average size is approximately 8 kilometers less than previously estimated, particularly at the poles.

“According to the Juno Radio occultation, Jupiter is smaller and more oblate, with a reduced size at the equator,” Garanti mentioned at the Europlanet Science Congress (EPSC) held in Helsinki, Finland on September 11.

Garanti and his team conducted 13 radio occultations with Juno, compared to the six combined by the Voyager and Pioneer missions, and calculated the diameter based on known wind speed measurements of Jupiter. For a pressure equivalent to one bar of gas (Earth’s sea-level atmospheric pressure), the planet’s diameter was measured to be 142,976 kilometers at the poles and 133,684 kilometers at the equator.

“Understanding the exact radius is essential, but it also aids in revealing the inner workings of the planet,” noted Oded Aharonson at the Weizmann Institute of Science, who did not participate in this study. “These new constraints will enable more accurate models of Jupiter’s interior, which are often complex and challenging to explore.”

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Source: www.newscientist.com

Astronomers Discover a Novel Type of Plasma Wave Orbiting Jupiter

Posted on July 11, 2025 by Igor Mitreski

Unusual Behaviour of Plasma at Jupiter’s Poles

NASA/JPL-CALTECH/SWRI/MS SS; Oleksuik © CC NC SA

Jupiter’s surrounding space is among the most unique in our solar system, and the plasma present is equally remarkable, exhibiting unprecedented wave patterns.

Robert Lysak, from the University of Minnesota, explores Aurora phenomena. These captivating displays of green and blue light on Earth are accompanied by nearly undetectable ultraviolet rays near Jupiter’s poles.

To comprehend the auroras on this distant planet, it’s vital to grasp the intricacies of the plasma that generates these lights—a mix of charged particles and atomic components that envelopes the planet. Insights gathered from NASA’s Juno spacecraft have led Lysak and his team to identify that Jupiter’s Auroral Plasma resonates with a novel type of wave.

This newly identified wave is a combination of two well-characterized types of plasma waves: the Alfven wave, which arises from the motion of charged particles, and the Langmuir wave, which corresponds to electron movement. Lysak points out that since electrons are much lighter than charged particles, these two kinds of waves typically oscillate at vastly different frequencies.

However, the environment near Jupiter’s poles possesses conditions ideal for both waves to oscillate together. This is enabled by the low density of the plasma in that region and the strong magnetic field exerted by the planet.

“The plasma characteristics observed are truly unique when compared to those in other parts of our solar system,” states John Leif Jorgensen at the Institute of Technology Denmark. With Juno’s data uncovering new wave patterns, he believes we can learn more about the magnetic attributes of distant exoplanets by looking for similar signals.

Juno is currently in orbit around Jupiter, with Lysak noting that if its mission is extended, it could provide unparalleled insights into the giant planet and its complexities. This mission, however, is one among several that may face cuts due to proposed NASA budget reductions.

“Discontinuing missions while they are yielding valuable data would be a significant setback for our field,” concludes Lysak.

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Source: www.newscientist.com

Webb Discovers Silicon Monoxide in the Atmosphere of Ultra-Hot Jupiter WASP-121b

Posted on June 3, 2025 by Igor Mitreski

Astronomers leveraging the NASA/ESA/CSA James Webb Space Telescope have identified water, carbon monoxide, and methane in the atmosphere of WASP-121B, as well as in Earth’s nightside atmosphere. This marks the first detection of silicon monoxide in any planetary atmosphere, including those within our solar system and beyond.

This artistic impression illustrates the phase during which WASP-121B collects most of its gas, inferred from recent findings. Image credit: T. Muller, MPIA & HDA.

WASP-121B is approximately 1.87 times larger and 1.18 times more massive than Jupiter.

First discovered in 2016, it completes an orbit around its host star, the F6-type WASP-121 (TYC 7630-352-1), in just 1.3 days, as observed by the WASP-SOUTH SURVEY.

The WASP-121 system is situated about 881 light years away in the constellation of Puppis.

Characterized as an Ultra Hot Jupiter, WASP-121B orbits its parent star in a mere 1.3 days, being so close that the star’s gravitational pull begins to physically disrupt it.

Estimates suggest that the temperatures on the planet’s eternal daytime side exceed 3,000 degrees Celsius, while the nightside cools down to around 1,500 degrees Celsius.

“The discovery of silicon monoxide in the atmosphere of WASP-121B is revolutionary, marking the first definitive identification of this molecule in any planetary atmosphere,” stated Dr. Anjali Piette, an astronomer at the University of Birmingham.

“The composition of the nightside atmosphere of WASP-121B indicates vertical mixing: the transport of gases from deeper atmospheric layers to the peak observed in infrared light.”

“We were surprised to find methane on the nightside given the extreme temperatures of this planet.”

Measurements of carbon-to-hydrogen, oxygen-to-hydrogen, silicon-to-hydrogen, and oxygen-to-oxygen ratios in the atmosphere suggest that during its formation, WASP-121B’s atmosphere was enriched by inner rocky materials enhanced by erosion-resistant bombardment.

“They’re outstanding,” remarked Dr. Thomas Evans Soma, an astronomer at Newcastle University.

In their research, astronomers employed a method known as phase curve observation, which entails tracking a planet’s orbit around its star and analyzing variations in its brightness.

These observations reveal details about both the daytime and nighttime hemispheres, along with their chemical makeups.

“The successful detection of these elements and characterization of WASP-121B’s atmosphere with Webb showcases the telescope’s capabilities and sets a precedent for future exploratory research,” Dr. Piette remarked.

Study published today in the journal Nature Astronomy.

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TM Evans-Soma et al. Ultra-Stellar C/O ratio in the atmosphere of SIO and giant exoplanet WASP-121. Nature Astronomy Published online on June 2, 2025. doi:10.1038/s41550-025-02513-x

Source: www.sci.news

Webb Captures Dynamic Infrared Auroras on Jupiter

Posted on May 13, 2025 by Igor Mitreski

Jovian auroras shine hundreds of times brighter than those visible from Earth, according to a team of astronomers led by Dr. Jonathan Nichols at the University of Leicester.

These observations of Jupiter’s aurora were captured on December 25, 2023 by Webb’s near-infrared camera (NIRCAM). Image credit: NASA / ESA / CSA / STSCI / RICARDO HUESO, UPV / IMKE DE PATER, UC BERKELEY / THIERRY FOUCHET, OBSERVATORY OF PARIS / LE FLETCHER, JOSEPH DEPASQUALE, STSCI/J. NICHOLS, UNIVERSITY OF LEICESTER/M. ZAMANI, ESA & WEBB.

When high-energy particles enter the planet’s atmosphere near its magnetic poles, they collide with gas atoms, creating the auroras.

Jupiter’s auroras are not only massive in scale but also exhibit energy levels hundreds of times greater than those seen on Earth.

These auroras are primarily triggered by solar storms, where charged particles entering the atmosphere excite gas particles, resulting in vibrant red, green, and purple hues.

Additionally, Jupiter has a unique source of auroral activity—its strong magnetic field captures charged particles from its surroundings.

This includes not only those from the solar wind but also particles ejected from the volcanic moon Io.

The eruptions from Io’s volcanoes release particles that escape both the moon’s and Jupiter’s gravitational pull.

Solar storms also discharge vast amounts of charged particles towards Jupiter.

Jupiter’s immense magnetic fields accelerate these charged particles to extraordinary speeds.

When these high-velocity particles collide with the planet’s atmosphere, they excite the gas and produce radiant displays.

https://www.youtube.com/watch?v=if0vpfergju

Thanks to the advanced capabilities of the NASA/ESA/CSA James Webb Space Telescope, new insights into Jovian auroras can be gained.

The telescope’s sensitivity enables astronomers to use faster shutter speeds to capture the rapidly evolving features of the auroras.

This latest data was collected using Webb’s near-infrared camera (NIRCAM) on Christmas Day 2023.

“What a Christmas gift; it truly astonished me!” exclaimed Dr. Nichols.

“We aimed to observe how quickly the aurora transformed, hoping to see beautiful fluctuations within about an hour.”

“Instead, we witnessed the entire aurora region illuminating the sky in a spectacular display.

Astronomers noted fluctuations in the effects caused by trihydrogen ions, known as H.³⁺, which varied more than previously assumed.

These observations help scientists unravel how Jupiter’s upper atmosphere undergoes heating and cooling.

Additionally, several unknown phenomena were identified in the data.

“What made these observations particularly intriguing was that the NASA/ESA Hubble Space Telescope was capturing images simultaneously in ultraviolet light,” Dr. Nichols commented.

“Strangely, the brightest light observed by Webb seemed to have no corresponding feature in Hubble’s images. This left me puzzled.”

“To produce the brightness observed in both Webb and Hubble, we would require an improbable mix of a substantial quantity of very low-energy particles impacting the atmosphere.

study Published in the journal Nature Communications.

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JD Nichols et al. 2025. The dynamic infrared aurora of Jupiter. Nature Communications 16, 3907; doi:10.1038/s41467-025-58984-z

Source: www.sci.news

What is the Formation Process of Super Jupiter?

Posted on March 24, 2025 by Igor Mitreski

scientist First discovered outside our solar systemcalled Planet1990s. Since then, scientists have found some strange systems. Turn robing from the first recorded exoplanet Neutron Star Jupiter-sized Exoplanet brings host stars into orbit Puts the sun in orbit nearly 20 times more than the Earthastronomers continue to find distant planetary systems that look very different from ours. It is a relatively easy exoplanet to find for astronomers. The gas giant is more than twice the mass of Jupiter, or more than 600 times the mass of Earth. Super Jupiter.

Astronomers have proposed two hypotheses on how some exoplanets can make this bigger. The first is that they form this size or grow from the gas and dust around the star’s first surroundings. Protoplanetary disc. The second is that it arises from collisions between two or more small gas giants. Scientists acknowledge that these hypotheses are not mutually exclusive, so some superjupiters can begin their size, while others can be formed by conflict.

However, scientists also say that the larger the Super Jupiter, the longer the longer, or Eccentric The formation mechanism should explain this observation, as its trajectory tends to be. They all agree that there is an answer to how planets interact. Collision advocates point out that hypothetical conflicts can distort Super Jupiter’s trajectory. Supporters of the high early mass say that gravitational pull from adjacent planets can also distort Super Jupiter’s orbit.

A team of astronomers recently tested these hypotheses on the Xplanet TOI-2145B and its host star TOI-2145. This exoplanet has a mass of about six times the mass of Jupiter and more than 1800 times the mass of Earth. They used accurate and detailed data collected by previous researchers from multiple sources. These included observations of the period, width, and distance from the star of the exporanet orbit. Passing an exoplanet survey satellite or Tess, and its mass and orbital eccentricity from Keck Observatory. High resolution Echelle spectrometer Or hire. This team collected their own data using Wiyn Telescope To enhance previous existing recruitment data. All the information was then combined to create a complete image of the stellar, orbital, and planetary properties of this system.

They discovered that TO-2145 stars are about 1.7 times the mass of the Sun, exceeding 1.5 billion years. Its exoplanet orbital is the Earth orbiting the Sun at a distance of over 1/10, causing a complete revolution in about 10 days, with a highly distorted orbit with an eccentricity of 0.2. For reference, Venus orbitalmost perfect circle and has an eccentricity of 0.007. Furthermore, the TOI-2145B’s trajectory is roughly aligned with the host star, with an axial tilt of approximately 7.o. For reference, the Earth has an axial tilt of 23.5othat causes our seasons. They also discovered that the system did not have any other measurable ex-man or nearby stars that could destroy the orbit of TOI-2145B.

The next step for astronomers was to use mathematical simulations to see if they could replicate a Super Jupiter with similar properties to the TOI2145B. Collision dynamics code was used rebound It models how a planetary system with a protranetary disc of a particular size and four starting planets has changed over 10 million years. They changed several parameters into the simulation, including the total mass of the four planets, how the masses were distributed between the planets, how far they were from each other, and the mass of the disc. They have the results of a few dozen simulations. Gaia Archives Check if you can replicate general trends in the Super Jupiter system.

To test the origin hypothesis of Super Jupiter, astronomers used simulations of relatively low protranetary disc masses to represent systems grown through collisions, and systems launched by Super Jupiter on a large scale using simulations of relatively high protranetary disc masses to represent systems started by Super Jupiter on a large scale. They found that the simulated Super Jupiter was consistently similar to the TOI2145B in terms of orbital size and eccentricity, whether the protranetary disc mass is high or low. However, their low-disk mass collision simulations replicated the trends of high-mass planets with more eccentric orbits, but at first, higher-disk mass simulations did not.

The team concluded that Super Jupiter is likely to originate from interplanetary collisions. However, they acknowledged that it is certainly possible for some exoplanets to begin their own lives several times larger than Jupiter.

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Source: sciworthy.com

Study finds that Chicxulub asteroid, which caused dinosaur extinction, originated from beyond Jupiter.

Posted on August 20, 2024 by Igor Mitreski

The asteroid, called the Chicxulub impactor, was a carbonaceous asteroid that formed outside the orbit of Jupiter. New Paper Published in the journal Science.

Ankylosaurus magniventrisA Tyrannosaurus, a type of large armored dinosaur, witnessed the impact of an asteroid that fell on the Yucatan Peninsula 66 million years ago. Image by Fabio Manucci.

About 66 million years ago, a 10-kilometer-wide asteroid struck Earth near what is now a small town called Chicxulub in Mexico.

This impact released incredible amounts of climate-changing gases into the atmosphere, setting off a chain of events that led to the extinction of the non-avian dinosaurs and 75% of life on Earth.

Evidence includes the presence of high concentrations of platinum group elements (PGE) in the Cretaceous-Paleogene boundary layer, including iridium, ruthenium, osmium, rhodium, platinum, and palladium, which are rare on Earth but common in meteorites.

These elevated PGE levels have been found worldwide, suggesting that the impact spread debris around the world.

Some have proposed large-scale volcanism in the Deccan Traps igneous province of India as an alternative source of PGEs, but the specific PGE ratios at the Cretaceous-Paleogene boundary are more consistent with an asteroid impact than volcanism.

However, little is known about the nature of the Chicxulub impactor, including its composition and extraterrestrial origin.

To answer these questions, Dr Mario Fischer-Gödde from the University of Cologne and his colleagues measured ruthenium isotopes in samples taken from three sites at the Cretaceous-Palaeogene boundary.

For comparison, the team also analysed samples from five other impacts that occurred between 36 million and 470 million years ago, an ancient impact spherule from 3.5 to 3.2 billion years ago, and two carbonaceous meteorites.

The researchers found that the ruthenium isotope signature of samples taken from the Cretaceous-Paleogene boundary was uniform and matched very closely to that of carbonaceous chondrites rather than those from Earth or other types of meteorites, suggesting that the Chicxulub impactor likely came from a carbonaceous-type asteroid that formed in the outer solar system.

The other five impact structures have isotopic signatures more consistent with silicic asteroids that formed closer to the Sun.

The ancient spherulitic samples are consistent with a carbonaceous asteroid impact during the final stages of Earth's accretion.

“The composition of this asteroid is consistent with that of carbonaceous asteroids that formed outside Jupiter's orbit during the formation of the solar system,” Dr Fischer-Gödde said.

“Asteroid impacts like Chicxulub turn out to be very rare and unique events in geological time,” said Professor Carsten Müncher from the University of Cologne.

“The fate of the dinosaurs and many other species was sealed by this object that came from the outer solar system.”

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Mario Fischer-Gedde others2024. Ruthenium isotopes indicate that the Chicxulub impactor was a carbonaceous asteroid. Science 385 (6710): 752-756; doi: 10.1126/science.adk4868

Source: www.sci.news

Study suggests Chicxulub asteroid that caused dinosaur extinction originated beyond Jupiter

Posted on August 17, 2024 by Igor Mitreski