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An illustration of Enceladus with its water plume emanating from the south pole (Credit: NASA/JPL-Caltech)

When Undergraduate Curiosity Uncovers Enceladus’ Uneven Space Environment

What began as a summer research project by an HKU undergraduate has developed into a peer-reviewed study revealing a striking asymmetry in the electron environment around Saturn’s icy moon Enceladus.   For HKU geology undergraduate Fiona LAW, an early curiosity about planetary science has led much further than she expected. A research project she began after her first year at HKU has now uncovered new clues about how Enceladus interacts with the charged particles surrounding Saturn. Fiona joined the Faculty of Science’s Summer Research Fellowship (SRF) Scheme after her first year, hoping to gain hands-on research experience and explore planetary science beyond the classroom. Enceladus, Saturn’s geologically active icy moon, is known for the water plume erupting from its south pole. The interaction between this activity and the surrounding plasma environment has made the moon an intriguing target for planetary scientists. Working under the supervision of Professor Zhonghua YAO, Associate Professor of Department of Earth and Planetary Sciences, Director of Laboratory for Space Science (LSR) and a member of The Hong Kong Institute for Astronomy & Astrophysics (HKIAA), Fiona investigated this complex environment using observations collected during NASA’s Cassini flybys of Enceladus. Professor Yao had initially proposed a project exploring possible connections between geological activity on icy moons and their surrounding space environments, laying the foundation for what would eventually become a publishable study.   Where the journey began “I never imagined that I would have the chance to lead a research project as a Year 1 student, and I am grateful to Professor Yao for entrusting me with this precious opportunity,” Fiona said. During the summer of her first year, Fiona was also allowed to attend international conferences in Earth and planetary sciences. The experience gave her an early glimpse into academic research, introduced her to cutting-edge developments in the field, and connected her with researchers from around the world. Fiona’s first SRF project appeared to conclude with an exciting finding. She identified what looked like a correlation between Enceladus’ south-polar water plume and the density of electrons above the region. The result seemed to suggest a possible connection between geological activity on the moon and the charged-particle environment surrounding it. However, research does not always follow the path researchers expect. When Fiona returned to the project after her second year and expanded the dataset, more detailed analysis showed that the apparent correlation was not a genuine physical relationship. Instead, it had arisen coincidentally from other patterns in the data. Rather than abandoning the project, Fiona, Professor Yao and other members of the research group began investigating what had produced those patterns in the first place. This gradually shifted the project towards a different question: how are electrons distributed around Enceladus, and does that distribution change depending on where the spacecraft passes the moon?   Upstream and downstream tell different stories To answer this question, the team systematically analysed data from Enceladus-targeted flybys conducted by NASA’s Cassini spacecraft, comparing measurements taken on the upstream and downstream sides of the moon. Much like water flowing around a rock in a stream, plasma in Saturn’s magnetosphere flows past Enceladus. This means the moon has an upstream side, facing the incoming plasma flow, and a downstream region, or wake, behind it. The researchers found that the two sides behave very differently. Downstream of Enceladus, electron density shows substantial depletion, while upstream of the moon the variations are comparatively minor. In other words, electrons are not distributed evenly around Enceladus: the surrounding plasma environment is distinctly asymmetric. The finding provides new insight into the physical processes operating around Enceladus and how the moon interacts with Saturn’s surrounding plasma environment. By comparing multiple Cassini flybys rather than focusing on a single encounter, the study offers a broader view of how electron density varies around the moon.   Turning an unexpected result into a discovery For Professor Yao, Fiona’s experience also demonstrates how modern research tools are making sophisticated scientific datasets increasingly accessible to younger researchers. “AI and other modern tools are making it far easier for younger students to get hands-on with real scientific data. They can quickly explore the fascinating world of science and make discoveries with truly fresh eyes. I hope that we’ll see many more undergraduates, and even high schoolers, joining our actual research projects in the years ahead,” Professor Yao said. The experience gave Fiona an unusually early opportunity to work with real spacecraft data, engage with the professional research community and contribute to frontier planetary science. It also taught her one of the most important lessons in research: an initial result that does not stand up to closer scrutiny is not necessarily a dead end. Sometimes, understanding why an expected answer is wrong can open the door to a more interesting question, and ultimately, an unexpected discovery. The resulting paper, “Asymmetric Distribution of Electron Density Near Enceladus: A Comparative Survey of Upstream and Downstream Cassini Flybys”, by Law et al., has been published in The Astrophysical Journal. The study reveals a pronounced difference in electron density between the upstream and downstream regions around Enceladus, providing new insights into the complex interaction between the icy moon and Saturn’s surrounding plasma environment.   View the paper with the following link: doi.org/10.3847/1538-4357/ae9150

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Artistic illustration of a light-driven reaction for constructing three-dimensional BCH molecular structures. Image credit: Emily R.-C. Yang.

HKU Chemists Harness Light to Build 3D Molecular Structures for Drug Discovery

Researchers from the Department of Chemistry at The University of Hong Kong (HKU), led by Professor Jian HE and collaborators, have developed a new light-driven method for constructing three-dimensional molecular building blocks that could give medicinal chemists greater flexibility in designing new drug candidates. The approach broadens the range of starting materials that can be used while suppressing unwanted polymerisation, overcoming key limitations of existing synthetic methods. The findings have been published in Nature Chemistry. Benzene rings are among the most common structural building blocks in medicines. They are chemically stable and provide a useful framework for positioning other functional groups within a drug molecule. However, their flat and relatively lipophilic nature can sometimes contribute to undesirable properties, such as poor water solubility or less favourable interactions with biological targets. Medicinal chemists are therefore increasingly exploring three-dimensional alternatives that can replace benzene rings while performing a similar structural role in drug molecules. One promising class is bicyclo[2.1.1]hexanes, or BCHs. Their compact, three-dimensional shape offers researchers another way to fine-tune the shape and properties of drug molecules, potentially improving characteristics such as solubility, selectivity and metabolic stability. One important route to BCHs involves combining bicyclo[1.1.0]butanes or BCBs with alkenes. BCBs are highly strained small-ring molecules that serve as useful starting materials for building more complex three-dimensional structures. However, synthesising structurally diverse BCHs has remained difficult. Existing methods may work only with a limited range of starting materials and can also trigger unwanted polymerisation or suffer from catalyst instability. Professor He’s team and their collaborators have now developed a new class of copper(I) photosensitisers that use visible light to drive this reaction. After absorbing light, the copper complex transfers energy to one of the starting materials, enabling BCH structures to form in a more controlled manner. The new strategy expands the range of starting materials that can be used and allows chemists to control where different chemical groups are positioned on the BCH scaffold. The team also demonstrated gram-scale synthesis and further modification of the resulting BCHs with a variety of functional groups, highlighting the method’s potential usefulness in medicinal chemistry and drug development. Professor Jian He expressed optimism about the potential impact of this discovery, stating, “The heteroleptic copper(I) photosensitisers developed by our team provide a new approach to the efficient and selective synthesis of BCHs. By modulating the triplet energy levels of copper complexes, we have effectively suppressed polymerisation side reactions and expanded the substrate scope to include electron-deficient alkenes, enynes, dienes, and even aliphatic alkenes. This opens new opportunities for sustainable chemical production and the development of more diverse drug candidates.”   Catalytic photosensitisation strategies for the synthesis of BCH bioisosteres via intermolecular cycloadditions. Image adapted from Tang et al., Nature Chemistry (2026).

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Tropical cyclone rainfall is shaped by storm intensity, atmospheric moisture and how efficiently that moisture is converted into rain. Illustration for conceptual purposes only.

HKU Study Reveals How Atmospheric Dryness Constrains Typhoon Rainfall, Leading to Lower-Than-Expected Increases

Under global warming, scientists have widely expected tropical cyclones (including typhoons and hurricanes) to bring more intense and frequent rainfall. The underlying physics seems intuitive: rising temperatures allow the atmosphere to hold more moisture, which, combined with intensifying storms, should theoretically trigger more destructive downpours. However, when researchers analyse climate model projections, they encounter a puzzling phenomenon: some models project rainfall increases that are far lower than what thermodynamics alone would predict. This uncertainty has long hindered the scientific community’s ability to accurately project future tropical cyclone precipitation and assess associated flood risks. Recently, a new study led by The University of Hong Kong (HKU) and Imperial College London (ICL) has uncovered a key missing piece of the puzzle: increasing atmospheric dryness. Published in Nature Geoscience, the work reveals that while a warmer atmosphere can indeed hold more moisture, it also becomes drier in a way that suppresses rainfall—effectively acting as a “brake” on tropical cyclone precipitation. Widening Atmospheric Unsaturation Obstructs Cloud Formation and Accelerates Evaporation The team, consisting of Professor Dazhi XI and Dr Jianan CHEN from the HKU Department of Earth and Planetary Sciences, and Professor Ralf TOUMI from ICL, analysed climate simulations, satellite observations, and reanalysis data. They found that as the climate warms, tropical cyclones become less efficient at converting moisture into rainfall. The team pointed out that the key lies in a physical mechanism known as the “column saturation deficit”—the gap between the actual amount of water vapour in the atmosphere and its level at complete saturation (the threshold for precipitation). Generally, rainfall occurs as water vapour condenses into cloud droplets, coalesces into raindrops, and falls to the ground. Under a warming climate, however, the atmosphere’s moisture-holding capacity increases exponentially. Consequently, even if relative humidity remains constant, the gap to “complete saturation” widens significantly, meaning the air becomes substantially drier. This dryness can possibly trigger two effects: Pre-landing Evaporation: Raindrops that condense at high altitudes in a typhoon are rapidly evaporated by dry air in the lower and middle troposphere during their descent, preventing them from reaching the ground. Inhibition of Condensation: As dry environmental air is entrained into the typhoon’s updraft, it dilutes the moisture supply, suppressing cloud and rain formation at the source. This constraining effect of atmospheric dryness is potent enough to offset the rainfall increases driven by storm intensification. This offers a robust physical explanation for why many climate models project rainfall increases that are consistently lower than traditional theoretical calculations. Pioneering a “Unified Assessment Framework” The study also proposes a unified framework for understanding tropical cyclone rainfall. It shows that rainfall depends not only on storm intensity and the amount of water vapour in the atmosphere, but also on precipitation efficiency—how efficiently that moisture is converted into rain. Two opposing effects in a warming climate shape this efficiency: greater storm intensity tends to boost it, while increased atmospheric dryness tends to suppress it. Although atmospheric dryness dominates in some climate models, this framework does not rule out an increase in precipitation efficiency if future storm intensification outweighs the suppressive effect of atmospheric dryness.  The findings could have important practical implications. For coastal communities, disaster managers, and infrastructure planners, more accurate projections of rainfall from future hurricanes and typhoons are critical for flood protection, evacuation planning, and climate resilience. By accounting for the effect of atmospheric dryness, the new framework could improve rainfall and flood-risk assessments and support better-informed climate adaptation planning. The study also notes that global climate models do not fully capture some fine-scale processes. Future high-resolution simulations will therefore be needed to refine the projections. Nevertheless, multiple datasets and models consistently show that greater atmospheric dryness reduces rainfall efficiency. This robust negative correlation underscores that atmospheric dryness is a critical thermodynamic constraint that must be incorporated into future climate projections. For details of the research, please refer to the journal paper “Future tropical cyclone rainfall constrained by increased atmospheric dryness”.  

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An illustration of Enceladus with its water plume emanating from the south pole (Credit: NASA/JPL-Caltech)

When Undergraduate Curiosity Uncovers Enceladus’ Uneven Space Environment

What began as a summer research project by an HKU undergraduate has developed into a peer-reviewed study revealing a striking asymmetry in the electron environment around Saturn’s icy moon Enceladus.   For HKU geology undergraduate Fiona LAW, an early curiosity about planetary science has led much further than she expected. A research project she began after her first year at HKU has now uncovered new clues about how Enceladus interacts with the charged particles surrounding Saturn. Fiona joined the Faculty of Science’s Summer Research Fellowship (SRF) Scheme after her first year, hoping to gain hands-on research experience and explore planetary science beyond the classroom. Enceladus, Saturn’s geologically active icy moon, is known for the water plume erupting from its south pole. The interaction between this activity and the surrounding plasma environment has made the moon an intriguing target for planetary scientists. Working under the supervision of Professor Zhonghua YAO, Associate Professor of Department of Earth and Planetary Sciences, Director of Laboratory for Space Science (LSR) and a member of The Hong Kong Institute for Astronomy & Astrophysics (HKIAA), Fiona investigated this complex environment using observations collected during NASA’s Cassini flybys of Enceladus. Professor Yao had initially proposed a project exploring possible connections between geological activity on icy moons and their surrounding space environments, laying the foundation for what would eventually become a publishable study.   Where the journey began “I never imagined that I would have the chance to lead a research project as a Year 1 student, and I am grateful to Professor Yao for entrusting me with this precious opportunity,” Fiona said. During the summer of her first year, Fiona was also allowed to attend international conferences in Earth and planetary sciences. The experience gave her an early glimpse into academic research, introduced her to cutting-edge developments in the field, and connected her with researchers from around the world. Fiona’s first SRF project appeared to conclude with an exciting finding. She identified what looked like a correlation between Enceladus’ south-polar water plume and the density of electrons above the region. The result seemed to suggest a possible connection between geological activity on the moon and the charged-particle environment surrounding it. However, research does not always follow the path researchers expect. When Fiona returned to the project after her second year and expanded the dataset, more detailed analysis showed that the apparent correlation was not a genuine physical relationship. Instead, it had arisen coincidentally from other patterns in the data. Rather than abandoning the project, Fiona, Professor Yao and other members of the research group began investigating what had produced those patterns in the first place. This gradually shifted the project towards a different question: how are electrons distributed around Enceladus, and does that distribution change depending on where the spacecraft passes the moon?   Upstream and downstream tell different stories To answer this question, the team systematically analysed data from Enceladus-targeted flybys conducted by NASA’s Cassini spacecraft, comparing measurements taken on the upstream and downstream sides of the moon. Much like water flowing around a rock in a stream, plasma in Saturn’s magnetosphere flows past Enceladus. This means the moon has an upstream side, facing the incoming plasma flow, and a downstream region, or wake, behind it. The researchers found that the two sides behave very differently. Downstream of Enceladus, electron density shows substantial depletion, while upstream of the moon the variations are comparatively minor. In other words, electrons are not distributed evenly around Enceladus: the surrounding plasma environment is distinctly asymmetric. The finding provides new insight into the physical processes operating around Enceladus and how the moon interacts with Saturn’s surrounding plasma environment. By comparing multiple Cassini flybys rather than focusing on a single encounter, the study offers a broader view of how electron density varies around the moon.   Turning an unexpected result into a discovery For Professor Yao, Fiona’s experience also demonstrates how modern research tools are making sophisticated scientific datasets increasingly accessible to younger researchers. “AI and other modern tools are making it far easier for younger students to get hands-on with real scientific data. They can quickly explore the fascinating world of science and make discoveries with truly fresh eyes. I hope that we’ll see many more undergraduates, and even high schoolers, joining our actual research projects in the years ahead,” Professor Yao said. The experience gave Fiona an unusually early opportunity to work with real spacecraft data, engage with the professional research community and contribute to frontier planetary science. It also taught her one of the most important lessons in research: an initial result that does not stand up to closer scrutiny is not necessarily a dead end. Sometimes, understanding why an expected answer is wrong can open the door to a more interesting question, and ultimately, an unexpected discovery. The resulting paper, “Asymmetric Distribution of Electron Density Near Enceladus: A Comparative Survey of Upstream and Downstream Cassini Flybys”, by Law et al., has been published in The Astrophysical Journal. The study reveals a pronounced difference in electron density between the upstream and downstream regions around Enceladus, providing new insights into the complex interaction between the icy moon and Saturn’s surrounding plasma environment.   View the paper with the following link: doi.org/10.3847/1538-4357/ae9150

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Fossil Shark Scales Reveal How Ocean Productivity Shapes Shark Resilience

  Why can shark populations withstand fishing pressure in one ocean, yet decline sharply in another just around 100 kilometres away? A new international study published in Science has revealed how differences in ocean productivity can shape shark abundance and resilience to human pressure. Dr Jonathan CYBULSKI, currently with the School of Biological Sciences and the Swire Institute of Marine Science (SWIMS) at The University of Hong Kong (HKU), was among the researchers involved in the study. The researchers reconstructed thousands of years of shark history on the Pacific and Caribbean sides of the Isthmus of Panama using dermal denticles — tiny, tooth-like scales shed naturally by sharks and preserved in seafloor sediments. Because different types of sharks produce denticles with different forms, these microscopic fossils provide scientists with a record of past shark communities. The method itself took more than a decade to build. “This project began 12 years ago with a wild idea to search for shark scales in reef sediments. Finding the first denticle was exhilarating,” said Dr. Erin Dillon (lead author) and collaborator of Dr. Cybulski at the Smithsonian Tropical Research Institute (STRI). “We had to work out what denticles could tell us, how to get them out of reef sediments and how to read a fossil assemblage. Panama represented the perfect place for applying the approach, because it let us compare shark baselines across two very different oceans separated by a single strip of land.”   By comparing denticles dating from several thousand years ago with those from the past century, the team was able to examine shark abundance before and after intensive human fishing. The results revealed a striking natural difference between the two oceans. Even before significant human exploitation, the Pacific side supported around 20 times more sharks than the Caribbean side, despite their geographical proximity and similarities in shark communities. Their responses to human pressure were also very different. Shark abundance in the Caribbean declined by around 75%, while no comparable decline was detected on the Pacific side even though it experienced >95% of the historical fishing pressure. The researchers attribute this contrast largely to differences in ocean productivity. Nutrient-rich Pacific waters support greater primary productivity and higher fish biomass, providing more food for sharks and potentially buffering their populations against fishing pressure. The less productive Caribbean naturally supports lower shark biomass, making its populations more vulnerable to additional human impacts. “This study shows the difference that environmental factors can play in controlling biomass in our oceans,” said Dr Cybulski. “In the Caribbean, with less nutrients and overall productivity, we have less shark biomass at the top of the food chain. Conversely, in the nutrient-rich Pacific with higher primary productivity, we have greater shark biomass through time.” During his postdoctoral research in Panama at STRI, following his PhD at HKU, Dr. Cybulski was involved in collecting reef-matrix cores from which Pacific shark denticles were recovered, and subsequently participated in the analysis and interpretation of the data. The findings are not, however, a clean bill of health for Pacific sharks. “Our samples from the recent time point are not capturing the whole story for modern shark populations, because our sampling methods averaged several hundreds of years’ worth of data,” said Dr. Cybulski. “We know that fishing in the Gulf of Panama, and globally, has increased in the last several decades. As a result of increased fishing effort, nearly 1/3 of all sharks and rays are now critically threatened. Additionally, human-induced climate change is altering known ocean productivity processes, such as upwelling in the Gulf of Panama. So, although we found the sharks in the Pacific may have a high capacity to recover, modern impacts from fishing and climate change may push them to a limit they have never experienced."   The findings highlight the importance of establishing historical ecological baselines when assessing changes in marine populations. Understanding how environmental conditions naturally influence shark abundance can help inform more realistic and locally appropriate conservation and recovery targets.   To access the paper, please visit: https://www.science.org/doi/10.1126/science.aec2144   Dr. Erin Dillon and team collecting a coral reef matrix core in the Gulf of Panama, Tropical Eastern Pacific.  (Credit: Sean Mattson) Variation in dermal denticle morphology. Denticles were imaged using a scanning electron microscope and false coloring applied. (Credit: Erin Dillon, Aaron O’Dea, and Jorge Ceballos) Observing shark dermal denticles under a microscope. (Credit: Isabelle Lee) Dr. Cybulski and team hammering in a coral reef matrix core in the Gulf of Panama, Tropical Eastern Pacific. (Credit: Jorge Aleman) Sub-sampling a coral reef matrix core for further processing. (Credit: Jonathan Cybulski) Coral reef matrix cores from a research expedition in the Gulf of Panama, Tropical Eastern Pacific. (Credit: Jonathan Cybulski)

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Artistic illustration of a light-driven reaction for constructing three-dimensional BCH molecular structures. Image credit: Emily R.-C. Yang.

HKU Chemists Harness Light to Build 3D Molecular Structures for Drug Discovery

Researchers from the Department of Chemistry at The University of Hong Kong (HKU), led by Professor Jian HE and collaborators, have developed a new light-driven method for constructing three-dimensional molecular building blocks that could give medicinal chemists greater flexibility in designing new drug candidates. The approach broadens the range of starting materials that can be used while suppressing unwanted polymerisation, overcoming key limitations of existing synthetic methods. The findings have been published in Nature Chemistry. Benzene rings are among the most common structural building blocks in medicines. They are chemically stable and provide a useful framework for positioning other functional groups within a drug molecule. However, their flat and relatively lipophilic nature can sometimes contribute to undesirable properties, such as poor water solubility or less favourable interactions with biological targets. Medicinal chemists are therefore increasingly exploring three-dimensional alternatives that can replace benzene rings while performing a similar structural role in drug molecules. One promising class is bicyclo[2.1.1]hexanes, or BCHs. Their compact, three-dimensional shape offers researchers another way to fine-tune the shape and properties of drug molecules, potentially improving characteristics such as solubility, selectivity and metabolic stability. One important route to BCHs involves combining bicyclo[1.1.0]butanes or BCBs with alkenes. BCBs are highly strained small-ring molecules that serve as useful starting materials for building more complex three-dimensional structures. However, synthesising structurally diverse BCHs has remained difficult. Existing methods may work only with a limited range of starting materials and can also trigger unwanted polymerisation or suffer from catalyst instability. Professor He’s team and their collaborators have now developed a new class of copper(I) photosensitisers that use visible light to drive this reaction. After absorbing light, the copper complex transfers energy to one of the starting materials, enabling BCH structures to form in a more controlled manner. The new strategy expands the range of starting materials that can be used and allows chemists to control where different chemical groups are positioned on the BCH scaffold. The team also demonstrated gram-scale synthesis and further modification of the resulting BCHs with a variety of functional groups, highlighting the method’s potential usefulness in medicinal chemistry and drug development. Professor Jian He expressed optimism about the potential impact of this discovery, stating, “The heteroleptic copper(I) photosensitisers developed by our team provide a new approach to the efficient and selective synthesis of BCHs. By modulating the triplet energy levels of copper complexes, we have effectively suppressed polymerisation side reactions and expanded the substrate scope to include electron-deficient alkenes, enynes, dienes, and even aliphatic alkenes. This opens new opportunities for sustainable chemical production and the development of more diverse drug candidates.”   Catalytic photosensitisation strategies for the synthesis of BCH bioisosteres via intermolecular cycloadditions. Image adapted from Tang et al., Nature Chemistry (2026).

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Tropical cyclone rainfall is shaped by storm intensity, atmospheric moisture and how efficiently that moisture is converted into rain. Illustration for conceptual purposes only.

HKU Study Reveals How Atmospheric Dryness Constrains Typhoon Rainfall, Leading to Lower-Than-Expected Increases

Under global warming, scientists have widely expected tropical cyclones (including typhoons and hurricanes) to bring more intense and frequent rainfall. The underlying physics seems intuitive: rising temperatures allow the atmosphere to hold more moisture, which, combined with intensifying storms, should theoretically trigger more destructive downpours. However, when researchers analyse climate model projections, they encounter a puzzling phenomenon: some models project rainfall increases that are far lower than what thermodynamics alone would predict. This uncertainty has long hindered the scientific community’s ability to accurately project future tropical cyclone precipitation and assess associated flood risks. Recently, a new study led by The University of Hong Kong (HKU) and Imperial College London (ICL) has uncovered a key missing piece of the puzzle: increasing atmospheric dryness. Published in Nature Geoscience, the work reveals that while a warmer atmosphere can indeed hold more moisture, it also becomes drier in a way that suppresses rainfall—effectively acting as a “brake” on tropical cyclone precipitation. Widening Atmospheric Unsaturation Obstructs Cloud Formation and Accelerates Evaporation The team, consisting of Professor Dazhi XI and Dr Jianan CHEN from the HKU Department of Earth and Planetary Sciences, and Professor Ralf TOUMI from ICL, analysed climate simulations, satellite observations, and reanalysis data. They found that as the climate warms, tropical cyclones become less efficient at converting moisture into rainfall. The team pointed out that the key lies in a physical mechanism known as the “column saturation deficit”—the gap between the actual amount of water vapour in the atmosphere and its level at complete saturation (the threshold for precipitation). Generally, rainfall occurs as water vapour condenses into cloud droplets, coalesces into raindrops, and falls to the ground. Under a warming climate, however, the atmosphere’s moisture-holding capacity increases exponentially. Consequently, even if relative humidity remains constant, the gap to “complete saturation” widens significantly, meaning the air becomes substantially drier. This dryness can possibly trigger two effects: Pre-landing Evaporation: Raindrops that condense at high altitudes in a typhoon are rapidly evaporated by dry air in the lower and middle troposphere during their descent, preventing them from reaching the ground. Inhibition of Condensation: As dry environmental air is entrained into the typhoon’s updraft, it dilutes the moisture supply, suppressing cloud and rain formation at the source. This constraining effect of atmospheric dryness is potent enough to offset the rainfall increases driven by storm intensification. This offers a robust physical explanation for why many climate models project rainfall increases that are consistently lower than traditional theoretical calculations. Pioneering a “Unified Assessment Framework” The study also proposes a unified framework for understanding tropical cyclone rainfall. It shows that rainfall depends not only on storm intensity and the amount of water vapour in the atmosphere, but also on precipitation efficiency—how efficiently that moisture is converted into rain. Two opposing effects in a warming climate shape this efficiency: greater storm intensity tends to boost it, while increased atmospheric dryness tends to suppress it. Although atmospheric dryness dominates in some climate models, this framework does not rule out an increase in precipitation efficiency if future storm intensification outweighs the suppressive effect of atmospheric dryness.  The findings could have important practical implications. For coastal communities, disaster managers, and infrastructure planners, more accurate projections of rainfall from future hurricanes and typhoons are critical for flood protection, evacuation planning, and climate resilience. By accounting for the effect of atmospheric dryness, the new framework could improve rainfall and flood-risk assessments and support better-informed climate adaptation planning. The study also notes that global climate models do not fully capture some fine-scale processes. Future high-resolution simulations will therefore be needed to refine the projections. Nevertheless, multiple datasets and models consistently show that greater atmospheric dryness reduces rainfall efficiency. This robust negative correlation underscores that atmospheric dryness is a critical thermodynamic constraint that must be incorporated into future climate projections. For details of the research, please refer to the journal paper “Future tropical cyclone rainfall constrained by increased atmospheric dryness”.  

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Mummified Hemidactylus frenatus found on the motherboard of an air conditioning unit on Saipan, Com-monwealth of the Northern Mariana Islands. Photo credit: respective paper in Discover Life

When Invasive Geckos Meet Modern Technology

House geckos are familiar nighttime visitors throughout much of tropical Asia and the Pacific, often seen stalking insects on walls and ceilings near artificial lights. But Common House Geckos can have a much more costly interaction with the human environment when they find their way inside electrical equipment. In a newly published study in Discover Life, Honorary Professor Hinrich Kaiser of the School of Biological Sciences at The University of Hong Kong (HKU) and Przemysław Zdunek report repeated incidents in which introduced Common House Geckos (Hemidactylus frenatus) entered outdoor air-conditioning units on the Pacific island of Saipan and were electrocuted after coming into contact with electronic circuitry. The encounters short-circuited the units’ motherboards and rendered the air conditioners inoperative. The study began with what initially appeared to be an unusual isolated incident. In March 2020, an air-conditioning unit at a residence on Saipan stopped producing cool air after having remained unused for several weeks. When a technician opened the outdoor compressor, an adult gecko was found fused to its motherboard. Replacing the circuit board restored the unit to operation. Less than three months later, the problem returned on a much larger scale. Three of four air-conditioning systems at the same residence failed simultaneously. Inspection revealed multiple dead geckos on each of the three motherboards—seven animals in total, including two egg-bearing females. Once again, replacement of the damaged circuit boards restored the units. “What initially looked like a bizarre one-off event suddenly became something much more interesting,” Professor Kaiser said. “We had geckos repeatedly entering air conditioners, dying on the electronics, and taking expensive equipment with them. That made us wonder how widespread this interaction between animals and technology might actually be.” Why would a gecko enter an air conditioner? The answer may lie in the same characteristics that have made house geckos highly successful at living alongside humans throughout the tropics. Electronic components can remain warmer than their surroundings, providing ectothermic animals such as geckos with attractive sites for thermoregulation. Enclosed electrical equipment may also offer shelter from predators and protected locations associated with reproduction. Unfortunately for a gecko, crossing electrically charged contacts on a circuit board can transform an apparently desirable refuge into a death trap. Professor Kaiser and Zdunek therefore searched the scientific literature and other published sources for similar incidents. They identified reports from Australia, Cuba and Taiwan involving geckos damaging air conditioners, televisions, computers and other electrical equipment. Previous research in Taiwan documented repeated gecko-induced short circuits in air conditioners, while work in Cuba reported dozens of incidents involving electrical appliances. The consequences can extend beyond an inconvenient repair bill. Geckos have also been implicated in failures involving electrical meter rooms and high-voltage switchboards, raising the possibility of electrical fires and risks to people working with affected equipment. A small animal with potentially large economic consequences The problem may become increasingly relevant as air conditioning and other electronic infrastructure become more widespread in regions affected by extreme heat. “House geckos are extraordinarily successful at living alongside people,” Professor Kaiser said. “As humans install more electronic equipment in warm climates, we are also unintentionally creating more opportunities for these animals to interact with that technology.” The authors emphasise that the problem is likely to be underreported. Technicians may replace a failed circuit board without identifying the animal responsible, while appliance owners may never learn why their equipment stopped working. Preventing access may therefore be more effective than attempting to control the geckos themselves. The study discusses approaches including screening ventilation and drainage openings and sealing other entry points, while maintaining the airflow and drainage required by the equipment. The observations also illustrate a broader and less recognised consequence of biological invasions. The Common House Gecko has spread widely beyond its native range through its association with human transportation and settlements. Its impacts are generally considered in ecological terms, including interactions with native species. The new study demonstrates that successful invasive species can also have unexpected consequences for human infrastructure. “Biological invasions do not stop at the boundary between nature and technology,” Professor Kaiser said. “An animal weighing only a few grams can short-circuit an expensive piece of equipment. These interactions are easy to overlook, but multiplied across tropical cities and millions of appliances, their economic consequences could become significant.” The paper, “Air conditioning units as death traps for introduced Common House Geckos, Hemidactylus frenatus, on Saipan, Commonwealth of the Northern Mariana Islands, with a discussion of impacts,” was published in Discover Life in August 2026.

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HKU to Host Prestigious MOP Conference in 2028 Marking Historic Debut in Hong Kong and Convening Global Outer Planetary Magnetosphere Experts

The University of Hong Kong (HKU) has successfully secured the hosting rights for the 2028 Magnetospheres of Outer Planets (MOP) Conference. As the premier global symposium in space physics, MOP has been held biennially since the 1970s and will make its historic debut in Hong Kong in 2028, more than half a century after its inception. Jointly hosted by the Hong Kong Institute for Astronomy and Astrophysics (HKIAA) and the Laboratory for Space Research (LSR) at HKU, this landmark event marks a major milestone in establishing Hong Kong’s leadership in space and planetary sciences across the Asia-Pacific region and globally. The announcement was officially made following the 2026 MOP Conference in Toulouse, France, held from July 26 to 31, 2026. During the week-long event, a delegation of HKU scholars delivered multiple invited talks, showcasing the University’s cutting-edge research and its international influence in outer planetary physics. Leveraging this scientific momentum, the HKU team formally proposed Hong Kong as the next host, receiving unanimous support from both the International Scientific Committee and conference delegates. The MOP Conference is the premier international symposium dedicated to exploring giant planet environments. Held biennially, MOP brings together leading space physicists, planetary scientists, and mission experts from around the globe—including key researchers from NASA, the European Space Agency (ESA), the Japan Aerospace Exploration Agency (JAXA), and other leading research institutions worldwide. The conference serves as a flagship venue for sharing updates on major space missions, plasma physics models, and findings from data analyses, including Voyager, Galileo, Cassini, Juno, Europa Clipper and JUICE (Jupiter Icy Moons Explorer). Winning the bid to host this prestigious event is a resounding testament to HKU’s outstanding academic achievements and its growing international stature in space physics. Beyond academic exchange, the 2028 MOP will focus heavily on the global roadmap for deep-space exploration over the next decade. Hundreds of top scientists will convene in Hong Kong to explore international collaboration on major Jupiter exploration missions, including China’s Tianwen-4, NASA’s Europa Clipper, and ESA’s JUICE mission. In addition to fostering global scientific partnerships and highlighting Hong Kong’s growing prominence in space exploration, the conference aims to inspire the next generation of local talent to pursue careers in space science and contribute to aerospace advancements both nationally and globally. HKU will announce further details on the dates, venue arrangements, and programme committee in due course. Further details about the conference can be found at https://lasp.colorado.edu/mop/resources/mop-conference.

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