Planetary scientists at the University of California, Berkeley, now say that hailstorms of mushballs accompanied by fierce lightning actually exist on Jupiter. In fact, mushball hailstorms may occur on all gaseous planets in the galaxy, including our solar system’s other giant planets, Saturn, Uranus and Neptune.

The idea of mushballs was initially put forth in 2020 to explain nonuniformities in the distribution of ammonia gas in Jupiter’s upper atmosphere that were detected both by NASA’s Juno mission and by radio telescopes on Earth.

At the time, UC Berkeley graduate student Chris Moeckel and his adviser, Imke de Pater, professor emerita of astronomy and of earth and planetary science, thought the theory too elaborate to be real, requiring highly specific atmospheric conditions.

“Imke and I both were like, ‘There’s no way in the world this is true,'” said Moeckel, who received his UC Berkeley Ph.D. last year and is now a researcher at UC Berkeley’s Space Sciences Laboratory. “So many things have to come together to actually explain this, it seems so exotic. I basically spent three years trying to prove this wrong. And I couldn’t prove it wrong.”

The confirmation, reported March 28 in the journal Science Advances, emerged together with the first 3D visualization of Jupiter’s upper atmosphere, which Moeckel and de Pater recently created and describe in a paper that is now undergoing peer review and is posted on the preprint server arXiv.

The 3D picture of Jupiter’s troposphere shows that the majority of the weather systems on Jupiter are shallow, reaching only 10 to 20 kilometers below the visible cloud deck or “surface” of the planet, which has a radius of 70,000 km. Most of the colorful, swirling patterns in the bands that encircle the planet are shallow.

Some weather, however, emerges much deeper in the troposphere, redistributing ammonia and water and essentially unmixing what was long thought to be a uniform atmosphere. The three types of weather events responsible are hurricane-like vortices, hotspots coupled to ammonia-rich plumes that wrap around the planet in a wave-like structure, and large storms that generate mushballs and lightning.

“Every time you look at Jupiter, it’s mostly just surface level,” Moeckel said. “It’s shallow, but a few things — vortices and these big storms — can punch through.”

“Juno really shows that ammonia is depleted at all latitudes down to about 150 kilometers, which is really odd,” said de Pater, who discovered 10 years ago that ammonia was depleted down to about 50 km. “That’s what Chris is trying to explain with his storm systems going much deeper than we expected.”

Inferring planet composition from observations of clouds

Gas giants like Jupiter and Saturn and ice giants like Neptune and Uranus are a major focus of current space missions and large telescopes, including the James Webb Space Telescope, in part because they can help us understand the formation history of our solar system and ground truth observations of distant exoplanets, many of which are large and gaseous. Since astronomers can see only the upper atmospheres of faraway exoplanets, knowing how to interpret chemical signatures in these observations can help scientists infer details of exoplanet interiors, even for Earth-like planets.

“We’re basically showing that the top of the atmosphere is actually a pretty bad representative of what is inside the planet,” Moeckel said.

That’s because storms like those that create mushballs unmix the atmosphere so that the chemical composition of the cloud tops does not necessarily reflect the composition deeper in the atmosphere. Jupiter is unlikely to be unique.

“You can just extend that to Uranus, Neptune — certainly to exoplanets as well,” de Pater said.

The atmosphere on Jupiter is radically different from that on Earth. It’s primarily made of hydrogen and helium gas with trace amounts of gaseous molecules, like ammonia and water, which are heavier than the bulk atmosphere. Earth’s atmosphere is mainly nitrogen and oxygen. Jupiter also has storms, like the Great Red Spot, that last for centuries. And while ammonia gas and water vapor rise, freeze into droplets, like snow, and rain down continually, there is no solid surface to hit. At what point do the raindrops stop falling?

“On Earth, you have a surface, and rain will eventually hit this surface,” Moeckel said. “The question is: What happens if you take the surface away? How far do the raindrops fall into the planet? This is what we have on the giant planets.”

That question has piqued the interest of planetary scientists for decades, because processes like rain and storms are thought to be the main vertical mixers of planetary atmospheres. For decades, the simple assumption of a well-mixed atmosphere guided inferences about the interior makeup of gas giant planets like Jupiter.

Observations by radio telescopes, much of it conducted by de Pater and colleagues, show that this simple assumption is false.

“The turbulent cloud tops would lead you to believe that the atmosphere is well mixed,” said Moeckel, invoking the analogy of a boiling pot of water. “If you look at the top, you see it boiling, and you would assume that the whole pot is boiling. But these findings show that even though the top looks like it’s boiling, below is a layer that really is very steady and sluggish.”

The microphysics of mushballs

On Jupiter, the majority of water rain and ammonia snow appears to cycle high up in the cold atmosphere and evaporate as it falls, Moeckel said. Yet, even before Juno’s arrival at Jupiter, de Pater and her colleagues reported an upper atmosphere lacking in ammonia. They were able to explain these observations, however, through dynamic and standard weather modeling, which predicted a rainout of ammonia in thunderstorms down to the water layer, where water vapor condenses into a liquid.

But radio observations by Juno traced the regions of poor mixing to much greater depths, down to about 150 km, with many areas puzzlingly depleted of ammonia and no known mechanism that could explain the observations. This led to proposals that water and ammonia ice must form hailstones that fall out of the atmosphere and remove the ammonia. But it was a mystery how hailstones could form that were heavy enough to fall hundreds of kilometers into the atmosphere.

To explain why ammonia is missing from parts of Jupiter’s atmosphere, planetary scientist Tristan Guillot proposed a theory involving violent storms and slushy hailstones called mushballs. In this idea, strong updrafts during storms can lift tiny ice particles high above the clouds — more than 60 kilometers up. At those altitudes, the ice mixes with ammonia vapor, which acts like antifreeze and melts the ice into a slushy liquid. As the particles continue to rise and fall, they grow larger — like hailstones on Earth — eventually becoming mushballs the size of softballs.

These mushballs can trap large amounts of water and ammonia with a 3 to 1 ratio. Because of their size and weight, they fall deep into the atmosphere — well below where the storm started — carrying the ammonia with them. This helps explain why ammonia appears to be missing from the upper atmosphere: it’s being dragged down and hidden deep inside the planet, where it leaves faint signatures to be observed with radio telescopes.

However, the process depends on a number of specific conditions. The storms need to have very strong updrafts, around 100 meters per second, and the slushy particles must quickly mix with ammonia and grow large enough to survive the fall.

“The mushball journey essentially starts about 50 to 60 kilometers below the cloud deck as water droplets. The water droplets get rapidly lofted all the way to the top of the cloud deck, where they freeze out and then fall over a hundred kilometers into the planet, where they start to evaporate and deposit material down there,” Moeckel said. “And so you have, essentially, this weird system that gets triggered far below the cloud deck, goes all the way to the top of the atmosphere and then sinks deep into the planet.”

Unique signatures in the Juno radio data for one storm cloud convinced him and his colleagues that this is, indeed, what happens.

“There was a small spot under the cloud that either looked like cooling, that is, melting ice, or an ammonia enhancement, that is, melting and release of ammonia,” Moeckel said. “It was the fact that either explanation was only possible with mushballs that eventually convinced me.”

The radio signature could not have been caused by water raindrops or ammonia snow, according to paper co-author Huazhi Ge, an expert in cloud dynamics on giant planets and a postdoctoral fellow at the California Institute of Technology in Pasadena.

“The Science Advances paper shows, observationally, that this process apparently is true, against my best desire to find a simpler answer,” Moeckel said.

Coordinated observations of Jupiter

Scientists around the world observe Jupiter regularly with ground-based telescopes, timed to coincide with Juno’s closest approach to the planet every six weeks. In February 2017 and April 2019 — the periods covered by the two papers — the researchers used data from both the Hubble Space Telescope (HST) and the Very Large Array (VLA) in New Mexico to complement Juno observations in an attempt to create a 3D picture of the troposphere. The HST, at visible wavelengths, provided measurements of reflected light off the cloud tops, while the VLA, a radio telescope, probed tens of kilometers below the clouds to provide global context. Juno’s Microwave Radiometer explored the deep atmosphere of Jupiter over a limited region of the atmosphere.

“I essentially developed a tomography method that takes the radio observations and turns them into a three-dimensional rendering of that part of the atmosphere that is seen by Juno,” Moeckel said.

The 3D picture of that one swath of Jupiter confirmed that most of the weather is happening in the upper 10 kilometers.

“The water condensation layer plays a crucial role in controlling the dynamics and the weather on Jupiter,” Moeckel said. “Only the most powerful storms and waves can break through that layer.

Moeckel noted that his analysis of Jupiter’s atmosphere was delayed by the lack of publicly available calibrated data products from the Juno mission. Given the current level of data released, he was forced to independently reconstruct the mission team’s data processing methods — tools, data and discussions that, if shared earlier, could have significantly accelerated independent research and broadened scientific participation. He has since made these resources publicly available to support future research efforts.

The work was funded in part by a Solar System Observations (SSO) award from NASA (80NSSC18K1003).

The study, published in the May 2025 issue of The American Naturalist, found that the masked shrew (Sorex cinereus) reduces its body mass by 13 percent in the colder months; the creature then grows larger in spring when conditions improve. In addition to a shrinking body, the team also found seasonal changes in the height of the creature’s braincase (the portion of the skull that houses and protects the brain) and the length of the femur.

“Shrinking the body and its parts is in fact a clever survival strategy,” says McLean. “And it’s one that’s important for us to understand as mammals face a constantly changing planet.”

Known as Dehnel’s phenomenon, this seasonal shrinking has been observed in other mammals but most often in shrews, which are small, insect-eating animals unrelated to rodents. Dehnel’s phenomenon is an extreme example of “phenotypic plasticity” — the ability of an organism to alter its physical form in response to environmental changes.

“We don’t know how common Dehnel’s phenomenon is among mammals, but we know it is rarer in nature than other energy-saving strategies mammals use, like hibernation,” said McLean.

McLean and his team of graduate and undergraduate students analyzed 125 masked shews that were trapped in North Carolina’s Pisgah National Forest from 2021 to 2023. The team used “pitfall traps” buried in leaf litter to capture the shrews. The animals were weighed in the field, then brought to UNCG’s Joint School of Nanoscience and Nanotechnology for microCT scans to examine various skeletal dimensions. Specimens and associated data are archived in the UNCG Mammal Collection. Researchers from Georgia Southern University were also involved in the research.

“Our population of masked shrews is the southern-most yet studied for these multiple different traits,” said McLean, “and the femur measurements we made are the first to show the magnitude of seasonal change in the long bones of the skeleton. This shows that shrews rapidly remodel much of their skeleton.”

Most prior studies of the phenomenon come from Europe. To place their new results in context, the researchers also conducted a meta-analysis of 74 other studies from across the Northern Hemisphere, combining that research with their own findings to understand what factors drive Dehnel’s phenomenon. McLean and his team developed statistical models that accurately predicted the amount of body shrinkage they observed based solely on the climate at the North Carolina site.

“This analysis reveals the generality of Dehnel’s phenomenon in Sorex shrews,” explains McLean. “Across many populations of shrews on three continents, the degree of body mass and braincase height shrinkage is greatest in areas with the lowest cool-season temperatures. So, fall and winter temperatures predict Dehnel’s phenomenon in these animals.”

“Phenotypic plasticity is a key way that shrews and many other species respond to changes in temperature,” McLean notes. “By learning more about this process, we can start to understand how mammals buffer against rapidly changing climates.”

Ramirez-Marquez, associate professor and division director of Enterprise Science and Engineering at Stevens, who grew up in the earthquake-prone Mexico City knows this first-hand. “Whenever there’s an earthquake, a city-wide alarm goes off and everybody leaves wherever they are and stays in the middle of the street — that’s a prevention phase,” he says. “Then there’s a restoration phase when people engage with others in the community, whether it’s sharing food and water or helping rescue people from under the debris.” The community’s solidarity and togetherness — one for all and all for one, per a Latin proverb — are key to bouncing back.

In scientific terms, this togetherness is defined as community cohesion, which encapsulates the sense of belonging, mutual support among members and shared values or sentiments, all of which boost community’s ability to withstand disasters. But whether this cohesion directly influences how well a community recovers from extreme events is not known, explains Alexander Gilgur who had studied this subject with Ramirez-Marquez as a Ph.D. student. “Resilience is a measure of how quickly and/or effortlessly the system recovers from a disturbance,” says Gilgur. “The causal relationship between cohesion and resilience appears logical, but it has not been proven mathematically.”

To address that issue, Gilgur and Ramirez-Marquez developed mathematical techniques to measure community cohesion and its resilience, which they outlined in a recent paper, published in the journal of Socio-Economic Planning Sciences. They investigated two case studies of the same San Francisco Bay Area community during 2020 wildfires and during 2022-23 rainstorms.

In their work, they found that during the less intense adverse events such the rainstorms, the community performance improved despite the increasing stress levels. However, in high-stress disturbances such as the wildfires, the community’s performance suffered. “We found that there’s a negative correlation between the resilience of a community and the strength of disturbance,” says Ramirez-Marquez.

In fact, in some cases, the disturbance could be so strong that people may forsake their community. Ramirez-Marquez cites the recent Los Angeles fires example (which wasn’t part of the study, but is telling), where more affluent residents hired private firefighters to keep their houses safe. “So when the stress is very strong, some might say, ‘oh, well, I don’t care about the community, I care about myself.’ The stress can be so high that the concept of community cohesion no longer stands.”

The scientists also found that the emotion intensity has a strong effect on community cohesion. “For helping communities be more resilient, emotional engagement is a very important factor,” says Gulgur, adding that it doesn’t matter whether emotions are positive or negative. “Anger and fear are equally powerful as joy and love.” On the contrary, people’s economic level does not have a direct effect on the community cohesion, “because the disaster might affect everyone,” says Ramirez-Marquez.

He notes that developing metrics to assess community cohesiveness and resilience offers practical benefits. If we can establish the causal link between cohesiveness and resilience, we can then set thresholds, limits or targets — and use these metrics to implement policies that aim to reach the desired numbers to improve resilience.

“Community cohesiveness is essentially a social glue that holds people together,” Ramirez-Marquez says. Quantifying that glue is challenging, yet being able to do so can help indicate whether a given community is resilient or can be stronger. “These metrics can then be used by policymakers to implement policies that make communities more resilient.”

The consequences of heavy drinking — which is defined as four or more drinks per occasion for women and five or more for men — are felt throughout the college community. These include blackouts, academic underperformance and interpersonal problems. Then there are the secondhand consequences for students who don’t drink, such as interrupted study, aggression, assault and having to care for intoxicated peers.

In a new study, researchers from the Brown University School of Public Health developed and tested an intervention called Counter-Attitudinal Advocacy (CAA). CAA involves advocating for a position that contradicts a personally held attitude or behavior. In this context, CAA targets positive perceptions of heavy drinking and the belief that alcohol is an essential part of college life.

In randomized controlled trials at two sites with 585 college students, researchers compared CAA to the well-established Personalized Normative Feedback (PNF) to evaluate their effectiveness in decreasing drinks per week, peak blood alcohol concentration and alcohol-related consequences relative to a control group. Researchers focused on drinks per week, a standard measure given the irregular drinking patterns of college students, who often veer between heavy drinking and alcohol-free days.

Ultimately, they worked on answering two main questions:

• Does CAA effectively reduce alcohol-related risk compared to our control?
• How does CAA compare to PNF, which has proven to be an effective low-cost way of reducing alcohol consumption among high-risk students?

Here’s what they found: Participants who received PNF reported significantly fewer drinks per week than the control group, while those who received CAA reported significantly fewer consequences. CAA had a harm reduction effect on consequences — its intended focus — but not on consumption of alcohol, which it did not target.

“Both interventions take just 5-10 minutes, making them ideal for broad prevention efforts,” said Kate Carey, co-lead investigator of the study and professor of behavioral and social sciences at Brown. “Our results showed that PNF did reduce alcohol consumption, as expected. But CAA specifically reduced the number of problems participants reported due to drinking. So, while they had different effects, they were complementary — giving us another useful tool for harm reduction.”

Carey explained that PNFs show participants how their drinking habits stack up against those of their peers, often exposing a common misconception that others drink more than they actually do: an insight that can help them adjust their own behavior. In contrast, CAA encourages participants to reflect on why it is a good idea to avoid alcohol-related problems, such as passing out or taking excessive risks, and to identify specific actions they can take to minimize these risks.

“Instead of directly telling students what to do, we prompt them to generate their own strategies,” Carey said. “This makes the intervention personalized and non-confrontational. Unlike some interventions that make people feel defensive about their drinking, CAA frames the discussion more broadly: ‘Why is it good for young people to avoid problems?’ rather than ‘You personally need to change.'”

As participants responded to these prompts, a research assistant or peer asked them to explain their written responses. Carey noted that this act of verbal reinforcement likely strengthened the intervention’s effect, since we tend to feel more committed to our viewpoints when we share them publicly.

It’s important to have a variety of brief interventions, since no single approach works for everyone, Carey stressed. Offering multiple evidence-based options increases the chances of reaching more people who are undergoing a period of heightened risk.

The research team, which includes co-primary investigators Angelo DiBello associate professor of applied and professional psychology at Rutgers University and Clayton Neighbors, professor of social psychology at the University of Houston, are encouraged that CAA provides another effective tool — especially for those who may not respond to PNF.