A led by researchers at the University of Hawaiʻi at Mānoa reveals that surface water ice in the Moon’s permanently shaded regions (PSRs) is less abundant than previously thought. The research provides the most detailed look yet into the lunar PSRs where sunlight cannot reach directly, suggesting that while ice may exist, it is likely present in low concentrations or small, isolated pockets.

This study builds on nearly a decade of breakthroughs by the team, led by Shuai Li, an associate researcher at the in the ÌÇÐÄVlog¹Ù·½ Mānoa . Li previously led the 2018 discovery of the first direct evidence of surface ice using data from India’s Chandrayaan-1 mission.

Less water on the Moon means future lunar explorers may face tighter constraints for sourcing drinking water and fuel, making planning and resource management even more critical.

Reflected sunlight, crater walls

In this latest effort, the team utilized NASA’s ShadowCam, an ultra-sensitive camera aboard the Korea Pathfinder Lunar Orbiter. ShadowCam is specifically designed to image the Moon’s darkest corners by capturing sunlight reflected off nearby crater walls.

Researchers found no evidence of “widespread” water ice at high concentrations (above 20% to 30% by weight). This discovery highlights a puzzling disparity between the Moon and other airless bodies like Mercury and Ceres, which host substantial, nearly pure ice deposits in their poles although the Moon’s poles are even colder.

While the delivery of water via impacts may be similar across the Moon and Mercury, Li suggests Mercury’s much hotter surface may facilitate substantially more water formation from solar wind than the Moon. Alternatively, the Moon’s unique environment—including space weathering from solar wind, volcanic degassing and mixing of rock layers from impact—may destroy or bury surface ice more effectively.

Science of light scattering

This study was made possible during ShadowCam’s extended mission, which allowed the team to capture images from multiple angles to analyze how light scatters off the lunar surface. This is the first time researchers used scattering properties of water ice to search for it on the Moon. Rocks and dust on the lunar surface sends more light back toward the direction from which it came, while water ice scatters light forward.

“Water ice doesn’t just make the surface brighter,” said Li. “The way it scatters light is a fingerprint. By using stereo observations to look at these shadowed craters from different perspectives, we were able to detect this distinctive forward-scattering behavior for the first time.”

In the high-resolution images, the team identified a few small areas, roughly 20 to 50 meters in size, that exhibit both high reflectance and unique forward-scattering properties. These optical signatures are consistent with ice concentrations greater than 10%.

Li said, “I thought we’d find more bright, ice-rich areas, so the small number we found was a bit surprising. However, the forward-scattering signal was a true and exciting surprise because it required stereo observations that were only possible during the extended mission.”

Liliane Burkhard, a University of Hawaiʻi at ²ÑÄå²Ô´Ç²¹ research affiliate, was selected as one of two for the European Geosciences Union (EGU) 2025 General Assembly in Vienna, Austria. In this week-long role spanning April and May, Burkhard created a large-scale installation that bridges science and art, specifically, transforming discarded conference posters into a floating cloud sculpture.

“Science is how we explain the world, art is how we make sense of it,” said Burkhard, a planetary geologist in the (HIGP) at the ÌÇÐÄVlog¹Ù·½ ²ÑÄå²Ô´Ç²¹ School of (SOEST). “I am deeply honored to be selected as an Artist in Residence for EGU25, where I can merge my passions for science and art in a meaningful way.”

The Artist in Residence program offers scientist-artists an opportunity to engage with scientific research in a dynamic setting and be inspired by the many new discoveries being presented at one of the largest international geoscience conferences.

“My installation served as a metaphor for how scientific ideas form and evolve, often starting as nebulous concepts that, over time, take shape and lead to something tangible,” Burkhard shared. “The act of reusing the physical posters to craft something new reflects the iterative process of research itself. In this, I hope to encourage viewers to consider how ideas, much like clouds, are always in flux: constantly forming and dissolving, yet impactful in the way they inspire both imagination and progress.”

With the installation, “Clouds of Insights,“ Burkhard created a space for reflection and conversation, while also emphasizing sustainability by repurposing materials from the conference itself.

In addition to her work as a sculptural mixed media artist, Burkhard has conducted planetary science research previously as a graduate student in the SOEST and now as a HIGP research affiliate. Through her investigations, she has explored the geology and histories of icy moons in our solar system, including Saturn’s largest moon, , and Jupiter’s largest moon, .

Sharing the science-art connection

Burkhard and Emily Costello, a researcher at HIGP, co-hosted a short course at the EGU conference, “Unlocking creativity through paper sculptures: Overcoming blocks in writing and idea generation.” They offered more than 60 attendees an opportunity to use the art of paper folding and sculpture to overcome creative blocks, spark fresh ideas and explore the transformative connections between hands-on creativity and scientific innovation.

“There was quite a lot of interest overall, which was very exciting!” said Burkhard. “The participants said they very much enjoyed doing something tactile and hands-on to help them with their work as scientists, connecting themselves to art and seeing things from a different perspective.”

—By Marcie Grabowski

Emily Costello, a planetary scientist at the University of Hawaiʻi at ²ÑÄå²Ô´Ç²¹, was as one of eight participating scientists to join its to the Jupiter Trojan asteroids. These asteroids are remnants of the early solar system trapped on stable orbits associated with, but not close to, the planet Jupiter.

On the Lucy mission, Costello will contribute to the goal of understanding the nature and history of Trojan asteroids by providing insights into the role of meteoritic impacts in shaping the surfaces of the Trojans.

“Impacts are a pervasive geological process on small bodies, so it is critical that we accurately decipher how these impacts shape the formation and evolution of the asteroids,” said Costello, who is a researcher at the in the ÌÇÐÄVlog¹Ù·½ ²ÑÄå²Ô´Ç²¹ (SOEST).

The impact of impacts

Launched in 2021, the spacecraft is the first space mission to explore the diverse group of small bodies known as the Jupiter Trojan asteroids. Trojan asteroids orbit in two “swarms” that lead and follow Jupiter in its orbit around the Sun.

Impacts from meteors mix the surface of these bodies and muddle geologic layers, called strata. Impacts play a crucial role in erasing and homogenizing certain surface features, such as crater rays, and in the evolution of chemical and physical characteristics. Costello will provide the Lucy team with a key piece of the surface geology puzzle, leveraging her impact modeling expertise and targeted observations of craters and the material they propel outward.

“The history written and rewritten by impacts will influence the interpretation of all observations by the Lucy mission’s scientific instruments that view Trojan surfaces,” Costello said. “So, it’s thrilling to be able to help interpret the first ever close-up look at these likely ancient asteroids.”

More about the Lucy mission

Over its 12-year mission, Lucy will explore a record-breaking number of asteroids, flying by three asteroids in the solar system’s main asteroid belt, and by eight Trojan asteroids that share an orbit around the Sun with Jupiter. Lucy also will fly by Earth three times to get a push from its gravity, making it the first spacecraft to return to the vicinity of Earth from the outer solar system.

and .

Related ÌÇÐÄVlog¹Ù·½ News stories on Costello:

• Linking planetary science, art, Indigenous culture focus of early career award, June 5, 2024
• Building pathways for Indigenous lunar science at ÌÇÐÄVlog¹Ù·½ ²ÑÄå²Ô´Ç²¹, June 17, 2022
• Mission to find lunar ice gets $3M NASA boost, February 1, 2022
• Surface of Jupiter’s moon Europa may have conditions for life, July 12, 2021

A team of undergraduate students from the University of Hawaiʻi at ²ÑÄå²Ô´Ç²¹ is one step closer to a potential deployment of its robotic rover to explore Mars.

“Team Robotic Space Exploration” (Team RoSE) is headed to Utah in late May to compete in the —the world’s premier robotics competition for college students.

“The team was in awe of the results, but is greatly motivated to improve upon our designs to be prepared for competition in Utah,” said lead systems integrator and student Jack Saito. “With less than 60 days left, the team is hoping to guarantee the success of our systems and eliminate any risks with thorough and persistent testing.”

After submitting a preliminary design and system acceptance review, the group was one of 38 teams selected to participate in the final round. More than 100 teams entered the competition.

“The entire team was ecstatic with the results knowing all the hard work and dedication had paid off; including all members from the past three years,” said project manager and mechanical engineering student Micah Chang. “It’s a great privilege for Team RoSE to participate in this magnificent event, and the team is excited for this opportunity to interact with peers and professionals from around the globe.”

Mission to Mars

The University Rover Challenge challenges teams to design and build the next generation of Mars rovers that may one day work alongside astronauts exploring the Red Planet.

Rovers will compete in four missions:

• Science mission to investigate a site for the presence of life
• Delivery mission to deliver a variety of objects to astronauts in the field across rugged terrain
• Equipment servicing mission to perform dexterous operations on a mock lander using a robotic arm
• Autonomous navigation mission to autonomously travel to a series of locations

“I’m so incredibly proud and impressed by the achievements of this highly motivated group of students,” said Frances Zhu, assistant researcher and the team’s advisor. “This undergraduate team formed just three years ago during the pandemic and now they are competing on the international stage.”

“This is the third time our ÌÇÐÄVlog¹Ù·½ ²ÑÄå²Ô´Ç²¹ team has entered this very prestigious competition and the first time they were selected,” said Trevor Sorensen, specialist/project manager and the team’s advisor. “Their teamwork and engineering skills are very impressive and I believed that this team would succeed. Go ‘Bows!”

VIP project

is one of approximately 20 (VIP) at ÌÇÐÄVlog¹Ù·½ ²ÑÄå²Ô´Ç²¹, which seek to foster long-term, in-depth, project-based learning to engage students and better prepare them for future careers. It consists of a faculty mentor, graduate student researchers and undergraduates.

“Robotic Space Exploration is an ideal example of a VIP team,” said Aaron Ohta, professor and VIP program director. “They are a multidisciplinary group of extremely talented and motivated students. This impressive accomplishment is a testament to their hard work and dedication.”

“This is why we encourage all our students to participate in VIP,” said College of Engineering Dean Brennon Morioka. “It exposes them to all the skill sets they will need in their careers and life—from the technical know-how to working with others to public speaking and leadership qualities.”

—By Marc Arakaki

As one of the most geographically isolated regions in the world, Hawaiʻi residents contend with the highest electricity prices in the U.S., about double the national average. This is due largely in part to a heavy dependence on imported petroleum and lack of fossil fuel resources.

However, below the Hawaiian Islands lies a geological hotspot in the Earth’s mantle that has been active for the past 70 million years, formed the island archipelago and continues to fuel Hawaiʻi’s active volcanoes. Because of this hotspot and the presence of subsurface heat, the use of geothermal energy can prove to be a viable option to solve some of the state’s energy woes.

Geothermal electricity is clean, inexpensive and firm—with the last meaning that is “always on” regardless of weather conditions or time of day. Geothermal also has the lowest land footprint compared to solar power and wind, and, unlike the other intermittent resources, no battery storage is needed. Currently, the state’s lone geothermal plant on Hawaiʻi Island produces five times the amount of electricity as one of the state’s largest solar farms, while requiring 80% less land area.

Evidence collected by the University of Hawaiʻi at ²ÑÄå²Ô´Ç²¹ suggests that all of the major Hawaiian Islands may hold the subsurface heat that is necessary to produce geothermal energy. However, the current state of understanding of geothermal potential outside of KÄ«lauea’s East Rift Zone (KERZ), the most active rift of the state’s most active volcano on Hawaiʻi Island, is very limited. KERZ is where geothermal exploration was focused in the 1970s, and is the only location in the Hawaiian archipelago where geothermal electric power is being produced.

Hawaiʻi Groundwater and Geothermal Resources Center

As Hawaiʻi is the only U.S. state without a geological survey, ÌÇÐÄVlog¹Ù·½ ²ÑÄå²Ô´Ç²¹ has contributed much of what is known about Hawaiʻi’s geology. Since producing Hawaiʻi’s first geothermal well in the 1970s, ÌÇÐÄVlog¹Ù·½ ²ÑÄå²Ô´Ç²¹ has spearheaded Hawaiʻi’s geothermal research, including producing the only two statewide resource assessments by Professors Donald Thomas and Nicole Lautze of the (HIGP) in 1985 and 2017, respectively. HIGP is housed in the ÌÇÐÄVlog¹Ù·½ ²ÑÄå²Ô´Ç²¹ .

Realizing the need to provide a central hub from which to disseminate data and information from their numerous geothermal and groundwater research projects throughout the state, Lautze and Thomas founded the (HGGRC) in 2014. HGGRC, led by Lautze, conducts research on Hawaiʻi’s fresh groundwater, geothermal (including shallow geothermal heat pump technology for building cooling) and carbon storage potential.

Hawaiʻi Play Fairway Project

The Hawaiʻi Play Fairway project was among HGGRC’s most important initiatives. ÌÇÐÄVlog¹Ù·½ ²ÑÄå²Ô´Ç²¹ was one of 11 initial phase I projects selected and funded by the U.S. Department of Energy from across the country to identify blind hydrothermal systems (those without surface expression). The project, led by Lautze, received subsequent phase II and III funding from 2014–20 and provided the first statewide geothermal assessment of the Hawaiian Islands since Thomas’ original report in 1985.

Ultimately, the Hawaiʻi Play Fairway Project provided an updated statewide geothermal resource assessment, expanded understanding of Hawaiʻi’s groundwater location and quality, and a roadmap for additional work to better characterize both resources. HGGRC’s philosophy is that more data will bring more knowledge, and that when this knowledge is shared with stakeholders and communities, more informed decisions can be made.

“I think nearly everyone in Hawaiʻi would value a low cost, low footprint, resilient, Indigenous, energy supply. But there are tradeoffs for some. If geothermal has a chance, community engagement will play a critical role,” said Lautze. “HGGRC will continue to work with stakeholders and local communities to advocate for the necessary funding to move the state one step closer to understanding and realizing its geothermal potential.”

She added, “The global geothermal community wonders why there isn’t more geothermal electricity generation in Hawaiʻi. The answer is complex, but I think that if we could get even a small power plant online in a location where the local community is supportive, I think it would be transformative for our state.”

For more on the Hawaiʻi Play Fairway Project objectives, . Noelo is ÌÇÐÄVlog¹Ù·½â€™s research magazine from the .

To the surprise of many planetary scientists, the oxidized iron mineral hematite has been discovered at high latitudes on the Moon. That’s according to a study led by Shuai Li, an assistant researcher at the (HIGP) in the University of Hawaiʻi at Mānoa (SOEST).

Iron is highly reactive with oxygen—forming reddish rust commonly seen on Earth. The lunar surface and interior, however, are virtually devoid of oxygen, so pristine metallic iron is prevalent on the Moon, and highly oxidized iron has not been confirmed in samples returned from the Apollo missions. In addition, hydrogen in solar wind blasts the lunar surface, which acts in opposition to oxidation. Thus, the presence of highly oxidized iron-bearing minerals, such as hematite, on the Moon is an unexpected discovery.

“Our hypothesis is that lunar hematite is formed through oxidation of lunar surface iron by the oxygen from the Earth’s upper atmosphere that has been continuously blown to the lunar surface by solar wind when the Moon is in Earth’s magnetotail during the past several billion years,” said Li.

To make the discovery, Li, HIGP professor Paul Lucey and co-authors from NASA’s Jet Propulsion Laboratory (JPL) and elsewhere analyzed the hyperspectral reflectance data acquired by the Moon Mineralogy Mapper (M3) designed by NASA JPL onboard India’s Chandrayaan-1 mission.

This new research was inspired by Li’s previous discovery of water ice in the Moon’s polar regions in 2018.

“When I examined the M3 data at the polar regions, I found some spectral features and patterns are different from those we see at the lower latitudes or the Apollo samples,” said Li. “I was curious whether it is possible that there are water-rock reactions on the Moon. After months of investigation, I figured out I was seeing the signature of hematite.”

The team found that the locations where hematite is present are strongly correlated with water content at high latitude Li and others found previously and are more concentrated on the nearside, which always faces the Earth.

“This discovery will reshape our knowledge about the Moon’s polar regions,” said Li. “Earth may have played an important role on the evolution of the Moon’s surface.”

For more see .

–By Marcie Grabowski

A alumna has been selected for the from the Heising-Simons Foundation. The three-year fellowship provides exceptional postdoctoral scientists with the opportunity to conduct research in planetary astronomy and the time and space to establish distinction and leadership in the field.

Emily First, PhD graduate in geology and geophysics in the (SOEST), will receive $375,000 to support her research at Cornell University to understand the composition of rocky planets across the galaxy by cataloging and interpreting geological signals.

Viewing a meteorite from Mars under a microscope served as a moment of awe for First, one of her early connections to the wonders of planetary science. With a wide-ranging background in geology, she is well equipped to tackle some of the most intriguing problems in exoplanet research today. From elucidating the history of Earth’s volcanic rocks to probing the origins of Moon rocks, she is an expert at considering minute details within their broader contexts.

“Emily will be generating the calibration set required to take advantage of the enormous data streams that will be arriving from the 2021 James Webb Space Telescope,” said Julia Hammer, SOEST earth sciences professor and First’s advisor during her doctoral work. “Given her skills in geology, petrology, sample analysis and numerical modeling, Emily is exceptionally well equipped to characterize sources of variability in the emission spectra of exotic rocks and contribute to our understanding of exoplanets.”

In her fellowship, First will gather diverse rock types from across the solar system that span a range of compositions and textures. After examining each specimen at a microscopic level, she will measure how the rocks absorb and emit light, and synthesize her findings into a robust and accessible dataset. Other planetary scientists will be able to compare this information to light signals from exoplanets to infer more about their compositional properties, and recognize ways these signals could be affected by rock textures and other physical properties. First’s interdisciplinary work will bridge the contributions of two fields, and support future research in determining the material compositions of potentially hundreds of exoplanets.

“Pursuing challenges in exoplanet research feels like a natural way to branch out from my background in geology,” said First. “It’s energizing to know that the database I’m building has the potential to support countless exoplanet research projects in the years to come.”

For the full story see .

—By Marcie Grabowski

For the first time, a cross-disciplinary study has shown chemical, physical, and material evidence for water formation on the Moon. Two teams from the collaborated on the project: physical chemists at the ÌÇÐÄVlog¹Ù·½ Mānoa Department of Chemistry’s W.M. Keck Research Laboratory in Astrochemistry and planetary scientists at the (HIGP).

Although recent discoveries by orbiting spacecraft such as the Lunar Prospector and the hard lander Lunar Crater Observation and Sensing Satellite suggest the existence of water ice at the poles the Moon, the origin of this water has remained uncertain. Lunar water represents one of the key requirements for permanent colonization of the Moon as a feedstock for fuel and energy generation (hydrogen, oxygen) and also as “drinking water.”

The breakthrough research is outlined in lead-authored by ÌÇÐÄVlog¹Ù·½ Mānoa postdoctoral fellow Cheng Zhu and colleagues in the Proceedings of the National Academy of Sciences.

Chemistry Professor Ralf I. Kaiser and HIGP’s Jeffrey Gillis-Davis designed the experiments to test the synergy between hydrogen protons from , lunar minerals and micrometeorite impacts. Zhu irradiated samples of olivine, a dry mineral that serves as a surrogate of lunar material, with deuterium ions as a proxy for solar wind protons.

Deuterium irradiated only “experiments did not reveal any trace of water formation, even after increasing the temperature to lunar mid-latitude daytime temperatures,” Zhu explained. “But when we warmed the sample, we detected molecular deuterium, suggesting that deuterium—or hydrogen—implanted from the solar wind can be stored in the lunar rock.”

Kaiser added, “Therefore, another high-energy source might be necessary to trigger water formation within the Moon’s minerals followed by its release as a gas that can be detected.”

The second set of deuterium irradiation experiments was followed by laser heating to simulate the thermal effects of micrometeorite impacts. A burst of ions with mass-to-charge ratios matching that of singly ionized heavy water was observed in the gas phase during the laser pulses. “Water continued to be produced during laser pulses after the temperature was increased, suggesting that the olivine was storing precursors to heavy water that were released by laser heating,” said Zhu.

To image these processes and interpret the broader impact on the Moon and other bodies, HIGP’s Hope Ishii and John Bradley used focused ion beam–scanning electron microscopy and transmission electron microscopy in the . They observed sub-micrometer-sized surface pits, some partially covered by lids, suggesting that water vapor builds up under the surface in vesicles until they burst, releasing water from lunar silicates upon micrometeorite impact.

“Overall, this study advances our understanding on the origin of water as detected on the Moon and other airless bodies in our Solar System such as Mercury and asteroids and provides, for the first time, a scientifically sound and proven mechanism of water formation,” HIGP’s Gillis-Davis concluded.

A team of scientists led by researchers from the University of Hawaiʻi at ²ÑÄå²Ô´Ç²¹ (SOEST) found the .

“We found that the distribution of ice on the lunar surface is very patchy, which is very different from other planetary bodies such as Mercury and Ceres where the ice is relatively pure and abundant,” said lead author , a postdoctoral researcher at the (HIGP) in SOEST. “The spectral features of our detected ice suggest that they were formed by slow condensation from a vapor phase either due to impact or water migration from space.”

The team analyzed data acquired by the Moon Mineralogy Mapper (M3) onboard India’s Chandrayaan-1 mission launched in 2008. They found absorption features in the M3 data that were similar to those of pure water ice measured in the laboratory. Their findings were further validated with data acquired by the Lunar Orbiter Laser Altimeter, the Lyman-Alpha Mapping Project and the Diviner instrument onboard America’s Lunar Reconnaissance Orbiter mission.

An elusive and surprising discovery

Before this research, there was no direct evidence of water ice on the lunar surface. Usually, M3 measures reflected light from the illuminated regions on the Moon. At PSRs, there is no direct sunlight reflected so M3 can only measure scattered light in those areas. Without an atmosphere, light bouncing around the surface of the Moon is scattered very weakly, producing a weak signal for the research team to work with.

“This was a really surprising finding,” said Li. “While I was interested to see what I could find in the M3 data from PSRs, I did not have any hope to see ice features when I started this project. I was astounded when I looked closer and found such meaningful spectral features in the measurements.”

Clues to the origin of water on the Moon and beyond

“The patchy distribution and smaller abundance of ice on the Moon compared with other planetary bodies suggest that the delivery, formation and retention processes of water ice on the Moon are very unique,” said , HIGP professor and study co-author.

“Given that the Moon is our nearest planetary neighbor, understanding the processes that led to water ice on the Moon provides clues to understand the origin of water on Earth and throughout the solar system,” said Li. “A future Moon mission is needed to examine the whole lunar PSRs to map out all water ices and understand the processes that led to water on the Moon. This work provides a roadmap for future exploration of the Moon, particularly the potential of water ice as a resource.”

The study published in the .

—By Marcie Grabowski

Two University of Hawaiʻi at ²ÑÄå²Ô´Ç²¹ scientists and a former postdoctoral fellow were honored at the 81st annual meeting of the Meteoritical Society, an international organization devoted to studies of meteorites and planetary science. The society was founded in 1933 and has more than 1,000 members from 52 countries.

Alexander Krot

Planetary scientist was awarded the Leonard Medal for outstanding contributions to the science of meteoritics and closely allied fields.

The research professor in the (HIGP) in the studies meteorites and cosmochemistry, with a focus on processes that took place before and while the planets were forming.

Linda Martel

, who provides academic support in HIGP, has won the Meteoritical Society’s Service Award. It is bestowed on members who have advanced the goals of the society to promote research and education in meteoritics and planetary science in ways other than by conducting scientific research.

Martel was recognized for her central role in creating , an educational website that informs the public about what meteoriticists do.

Lydia Hallis

Lydia Hallis, faculty member at Glasgow University in Scotland, was awarded the society’s Nier Prize, which recognizes outstanding research in meteoritics and allied fields by young (under age 35) scientists.

Hallis was a postdoctoral researcher in HIGP and the ÌÇÐÄVlog¹Ù·½ Institute for Astronomy from 2010 to 2014, and still collaborates with ÌÇÐÄVlog¹Ù·½ faculty members. Her research includes studies of lunar rocks, meteorites from Mars, the role of water in altering the Martian surface and on how Earth received its water.

For more information, see the .

—By Marcie Grabowski

An international team of scientists, led by researchers at the (MIT), have reconstructed the extreme collision that created one of the moon’s largest craters, 3.8 billion years ago. , a professor in the University of Hawaiʻi at Mānoa , was among the scientists who retraced the moon’s dramatic response in the first hours following the massive impact, and identified the processes by which large, multi-ring basins can form in the aftermath of such events.

The findings, published in two papers in the journal , may shed light on how giant impacts shaped the evolution of the moon, and even life on Earth, shortly after the planets formed.

• , Science, October 28, 2016
• , Science, October 28, 2016

The team’s results pertain to the moon’s Orientale basin, an expansive, bull’s eye-shaped depression on the southwestern edge of the moon, just barely visible from Earth. The basin is surrounded by three concentric rings of rock, the largest one stretching 580 miles across—about six times as wide as the Big Island of Hawaiʻi. Until now, it’s been unclear how massive impacts produced the complex structures displayed by multi-ring basins.

Probes on NASA’s (GRAIL) spacecraft took measurements of the basin’s gravity field at high spatial resolution, providing scientists with a precise map of the moon’s interior mass distribution which enabled the researchers to make revealing geophysical observations and develop a computer model to re-create the impact and its effects.

Taylor’s role in the mission focused on integrating information about the composition of the crust in and around the Orientale Basin into the interpretation of the gravity data.

“In short, using orbital remote sensing data, I helped put these amazing geophysical observations and computer modeling into a mineralogical and geochemical context,” said Taylor.

Measured impact

In one of two Science papers, , vice president for research and the E.A. Griswold Professor of Geophysics at MIT and her colleagues analyzed GRAIL’s gravity field measurements and were able to solve a key mystery, namely, the size and location of the basin’s transient crater, which is the initial depression created when an asteroid blasts material out from the lunar surface.

The researchers determined that the 3.8-billion-year-old basin was created by a huge impactor that punched an initial, transient crater into the lunar surface, measuring up to 285 miles in diameter. This impact, the researchers calculated, sent at least 816,000 cubic miles of pulverized lunar crust flying out from the impact site—an amount equivalent to 135 times the combined volume of the Great Lakes.

Making a bull’s-eye

In the second paper, led by Brandon Johnson, assistant professor at Brown University, the team created a computer simulation to reconstruct the first hours following the initial impact that created the Orientale basin. The team ran the simulation multiple times, with varying conditions, until the final basin and its concentric rings matched the observations made by GRAIL.

Based on these simulations, the team estimated that the basin was carved out by a 40-mile-wide object that collided with the moon at about 9 miles per second, or 32,400 miles per hour. The impact pulverized the underlying crust, and the propagation and subsequent unloading of the shockwave caused material to rise up, then crash back down, sloshing back and forth in a wave-like fashion for the next two hours. The material eventually settled back to the surface in the pattern of the basin’s two outermost rings, each rising several kilometers high.

The Orientale basin is considered a relatively pristine example of what the moon and the Earth experienced during a period in which the solar system was dominated by large, catastrophic impacts.

“Ultimately, what this tells us is that the early history of the planets, at the time life was developing on Earth, was an extraordinarily hostile environment,” Zuber says. “There were extreme, energetic events that produced remarkably difficult environmental conditions. Maybe that’s why life is as tenacious as it is, because life forms somehow developed in the time subsequent to these catastrophic events. They were tough little buggers.”

This research was supported by the NASA Discovery Program.

—Text courtesy of Jennifer Chu, MIT news office

—By Marcie Grabowski

A team of researchers from the University of Hawaiʻi at Mānoa that estimated the probability of a magnitude 9+ earthquake in the Aleutian Islands—an event with sufficient power to create a mega-tsunami especially threatening to Hawaiʻi. In the next 50 years, they report, there is a 9 percent chance of such an event. An earlier (Table 6.12) has estimated the damage from such an event would be nearly $40 billion, with more than 300,000 people affected.

Earth’s crust is composed of numerous rocky plates. An earthquake occurs when two sections of crust suddenly slip past one another. The surface where they slip is called the fault, and the system of faults comprises a subduction zone. Hawaiʻi is especially vulnerable to a tsunami created by an earthquake in the subduction zone of the Aleutian Islands.

Back to basics

“Necessity is the mother of invention,” said , lead author and geophysicist at the ÌÇÐÄVlog¹Ù·½ Mānoa . “Having no recorded history of mega tsunamis in Hawaiʻi, and given the tsunami threat to Hawaiʻi, we devised a model for magnitude 9 earthquake rates following upon the insightful work of .”

Butler and co-authors (SOEST) and William Templeton (now at Portland State University) created a numerical model based only upon the basics of plate tectonics: fault length and plate convergence rate, handling uncertainties in the data with Bayesian techniques.

Using the past to inform the future

To validate this model, the researchers utilized recorded histories and seismic/tsunami evidence related to the 5 largest earthquakes (greater than magnitude 9) since 1900 (Tohoku, 2011; Sumatra-Andaman, 2004; Alaska, 1964; Chile, 1960 and Kamchatka, 1952).

“These five events represent half of the seismic energy that has been released globally since 1900,” said Butler. “The events differed in details, but all of them generated great tsunamis that caused enormous destruction.”

To further refine the probability estimates, they took into account past (prior to recorded history) tsunamis—evidence of which is preserved in geological layers in coastal sediments, volcanic tephras, and archeological sites.

“We were surprised and pleased to see how well the model actually fit the paleotsunami data,” said Butler.

Mitigating the risk

Using the probability of occurrence, the researchers were able to annualize the risk. They report the chance of a magnitude 9 earthquake in the greater Aleutians is 9 percent ± 3 percent in the next 50 years. Hence the risk is 9 percent of $40 billion, or $3.6 billion. Annualized, this risk is about $72 million per year. Considering a worst-case location for Hawaiʻi limited to the Eastern Aleutian Islands, the chances are about 3.5 percent in the next 50 years, or about $30 million annualized risk. In making decisions regarding mitigation against this $30-$72 million risk, the state can now prioritize this hazard with other threats and needs.

The team is now considering ways to extend the analysis to smaller earthquakes, magnitude 7–8, around the Pacific.

—By Marcie Grabowski

Our solar system, and other planetary systems, started as a disk of microscopic dust, gas and ice around the young Sun. The amazing diversity of objects in the solar system today—the planets, moons, asteroids and comets—was made from this primitive dust.

NASA’s Stardust mission returned to Earth with samples of comet Wild 2, a comet that originated outside the orbit of Neptune and was subsequently kicked closer to Earth’s orbit in 1974, when Jupiter’s gravity altered Wild 2’s orbit.

Led by Assistant Researcher Ryan Ogliore, a team of scientists from ÌÇÐÄVlog¹Ù·½ Mānoa and the investigated the oxygen isotope and mineral composition of the comet dust returned from Wild 2.

Before Stardust returned, scientists thought that everything it brought back from the comet would be either this primitive dust or circumstellar grains—rocks and minerals that formed around other stars. This was not the case.

In a in , Ogliore and his colleagues discovered that the larger-sized dust appears to be similar to rocks found in primitive meteorites called chondrites. The smaller-sized dust, on the other hand, displays the entire range of known oxygen isotopic compositions that have been measured for objects from the inner solar system (from the Sun to the asteroid belt).

This unexpected combination of material has deepened the mystery of Wild 2’s past.

A story in every grain of dust

“So, now we ask the question: Does the fine-grained dust from comet Wild 2 represent a diverse sampling of many inner-solar-system objects that were transported to the outer solar system, or in fact, the raw starting materials of the solar system?” said Ogliore.

Fortunately, the team has a method to address that. Processing of material in the inner solar system should alter the abundance of circumstellar grains and volatile elements in the fine-grained dust.

“If the fine-grained material is enriched in circumstellar grains and not depleted in volatiles, we can say with certainty that we are looking at primitive solar system dust,” said Ogliore. “If circumstellar grains are not over-abundant compared to meteorites, and volatiles are depleted, we can say with certainty that we are looking at a very diverse sample of fine-grained inner solar system material in the comet.”

Reflecting on the complex life history of comet Wild 2’s constituent material, Ogliore added, “The comet’s nucleus today is made up of small rocks and ice, separated by fractions of an inch, that originally formed billions of miles apart. Some rocks have seen temperatures above 2,500 degrees Fahrenheit, but adjacent ice has been kept close to absolute zero for billions of years. Every tiny grain we look at has its own fascinating story to tell.”

• More on Comet Wild 2: March 9, 2012

—By Marcie Grabowski