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Spectacular clouds swirl across the surface of Jupiter. These clouds contain water, just like Earth’s, but are much denser on the gas giant—so thick that no spacecraft has been able to measure exactly what lies beneath.
But a new study led by University of Chicago and Jet Propulsion Lab scientists has given us a deeper look at the planet by creating the most complete model to date of Jupiter’s atmosphere.
Among other things, the analysis addresses a longstanding question about how much oxygen the gas giant contains: It estimates that Jupiter has about one and a half times more oxygen than the sun. This helps scientists narrow down the picture of how all the planets in the solar system formed.
“This is a long-standing debate in planetary studies,” said Jeehyun Yang, a postdoctoral researcher at UChicago and first author on the paper. “It’s a testament to how the latest generation of computational models can transform our understanding of other planets.”
The study was published Jan. 8 in The Planetary Science Journal.
Clouds and chemistry
We’ve known about Jupiter’s stormy skies for at least 360 years—that’s when astronomers using early telescopes documented a curious, large permanent blotch on Jupiter’s surface.
The Great Red Spot is a gigantic storm, twice the size of Earth, that has swirled for centuries. It’s just one of many on the planet, as fierce winds and deep clouds mean the entirety of Jupiter’s surface is covered in a kaleidoscope of storms.
What we don’t know is precisely what lies beneath those storms. The clouds are so thick that NASA’s Galileo spacecraft lost contact with Earth as it plunged into the deeper atmosphere in 2003. The next mission to visit Jupiter, Juno, is currently cataloguing the planet from a safe distance in orbit.
These measurements from orbit can tell us the components in the upper atmosphere: ammonia, methane, ammonium hydrosulfide, water and carbon monoxide, among others. Scientists have combined this with knowledge about chemical reactions to build models of Jupiter’s deep atmosphere.
But studies have disagreed about certain points, such as how much water—and thus oxygen—the planet contains. Yang saw an opportunity to apply a new generation of chemical modeling to the knotty question.
The chemistry of Jupiter’s atmosphere is incredibly complex. Molecules travel between the extremely hot conditions deep in the atmosphere and the cooler upper regions, changing phases and rearranging into different molecules, via thousands of different types of reactions. But the behavior of clouds and droplets has to be accounted for, too.
To better capture all these phenomena, Yang worked with a team of scientists to incorporate both chemistry and hydrodynamics into one model—a first.
“You need both,” Yang said. “Chemistry is important but doesn’t include water droplets or cloud behavior. Hydrodynamics alone simplifies the chemistry too much. So, it’s important to bring them together.”
Elemental questions
Among the findings is a new calculation for how much oxygen Jupiter has. According to their analysis, Jupiter likely has about one and a half times more than the sun.
For decades, scientists have been arguing about this number. A major recent study had put it much lower, at only a third of the sun’s.
But knowing this statistic is particularly relevant for understanding how our solar system formed.
All of the elements that make up planets—and us—are the same stuff that makes up the sun. But there can be differences in the amounts of these materials, and we can use those clues to piece together how the planets must have formed.
For example, did Jupiter form in the same place where it is now, or did it form closer or further away and drift over time? Clues can come from the fact that much of the oxygen in the planet is bound up in water, which will freeze—and behave differently—if it’s too far away from the warmth of the sun. Ice is easier for planets to accumulate than water vapor.
In turn, knowing more about which conditions create which kinds of planets can help us as we search for habitable planets beyond our own solar system.
The model also suggested that Jupiter’s atmosphere likely circulates up and down much more slowly than long believed.
“Our model suggests the diffusion would have to be 35 to 40 times slower compared to what the standard assumption has been,” said Yang. For example, it would take a single molecule several weeks to move through one layer of the atmosphere, rather than hours.
“It really shows how much we still have to learn about planets, even in our own solar system,” Yang said.
Citation: “Coupled 1D Chemical Kinetic-Transport and 2D Hydrodynamic Modeling Supports a modest 1–1.5× Supersolar Oxygen Abundance in Jupiter’s Atmosphere.” Yang et al, The Planetary Science Journal, Jan. 8, 2026.
Funding: NASA, Caltech-Jet Propulsion Laboratory.
