Unfortunately for science fiction fans, desert worlds outside our solar system are unlikely to host life, according to new research from 91̽��. Scientists show that an Earth-sized planet needs at least 20 to 50% of the water in Earth’s oceans to maintain a critical natural cycle that keeps water on the surface.

Scientists believe that there are billions of planets outside our solar system. More than are confirmed, but only some of them are candidates for life. The search for life has focused on planets in the “,” a sweet spot that is neither too close nor too far from a central star. Planets in this zone are considered viable because they can maintain liquid surface water.

“When you are searching for life in the broad landscape of the universe with limited resources, you have to filter out some planets,” said lead author , a 91̽��doctoral student of Earth and space sciences.

Water, although essential, does not guarantee the existence of life. With this study, researchers worked to further narrow the search by investigating planets with just a small amount of water.

“We were interested in arid planets with very limited surface water inventory — far less than one Earth ocean. Many of these planets are in the habitable zone of their star, but we weren’t sure if they could actually be habitable,” White-Gianella said.

The team’s results, , show that habitability hinges on the geologic carbon cycle — a water-driven process that exchanges carbon between the atmosphere and interior over millions of years, stabilizing surface temperatures.

Carbon dioxide, which comes from volcanoes in a natural system, accumulates in the atmosphere before falling back to Earth dissolved in rainwater. Rain erodes and chemically reacts with rocks on the Earth’s surface and runoff transports carbon to the ocean, where it sinks to the seafloor. Plate tectonics drives carbon-rich oceanic plates below continental land. Millions of years later, carbon resurfaces as mountains form.

If water levels drop too low for rainfall, carbon removal — from weathering — can’t keep up with emissions from volcanic eruptions and carbon dioxide levels in the atmosphere spike, trapping water. Rising temperatures evaporate the remaining surface water, initiating runaway warming that makes the planet too hot to support life.

“So that unfortunately makes these arid planets within habitable zones unlikely to be good candidates for life,” White-Gianella said.

Although scientists have instruments that can measure surface water, rocky exoplanets are difficult to observe directly. In this study, the researchers ran a series of complex simulations to better understand how water might behave in these desert worlds.

Previous efforts to model the carbon cycle focused on cooler, perhaps wetter planets. The models factored in evaporation from sunlight, but didn’t include other drivers, such as wind. White-Gianella adapted existing models to drier planets by refining evaporation and precipitation estimates.

“These sophisticated, mechanistic models of the carbon cycle have emerged from people trying to understand how Earth’s thermostat has worked — or hasn’t — to regulate temperature through time,” said senior author , a 91̽��assistant professor of Earth and space sciences.

However, the function of the geologic carbon cycle on arid planets was largely unexplored. The results show that even planets that form with surface water could lose it, transitioning from potentially habitable to uninhabitable due to carbon cycle disruption.

One such planet exists far closer to home: Venus. The planet of love is roughly the same size as Earth, likely formed around the same time and may have started with a similar amount of water.

Yet today, the surface of Venus rivals the temperature of a wood-fired pizza oven. Standing on the surface would feel like being crushed by 10 blue whales, White-Gianella said.

Many theories attempt to explain why Earth and Venus are so different. White-Gianella and Krissanen-Totton propose that Venus, being closer to the sun, may have formed with slightly less water than Earth, which imbalanced the geologic carbon cycle. As surface temperatures rose with atmospheric carbon dioxide levels, Venus lost its water — and any life it may have hosted.

Upcoming missions to Venus will attempt to understand what happened to the planet and whether it ever hosted life. The findings could also offer insight into planets much farther away.

“It’s very unlikely that we will land something on the surface of an exoplanet in our lifetime, but Venus — our nextdoor neighbor — is arguably the best exoplanet analog,” White-Gianella said.

The researchers hope that results from future missions will help validate the results of their modeling.

“This has implications for a lot of the potentially habitable real estate out there,” Krissanen-Totton said.

This study was funded by the National Science Foundation, the NASA Astrobiology Program and the Alfred P. Sloan Foundation.

For more information, contact White-Gianella at hasktw@uw.edu or Krissanen-Totton at joshkt@uw.edu.��

Nautilus and Allonautilus cephalopods and their extinct ancestors have been drifting through of the ocean for more than 500 million years. Researchers have spent the last 40 years trying to understand how these mysterious “living fossils” thrive in areas with limited nutrients. published in Scientific Reports, a UW-led team documented new habits and habitats for current Nautilus and Allonautilus species. These creatures appear to live in deeper water than their extinct cousins did, and the younger ones live twice as deep as the fully mature adults. Nautilus and Allonautilus species scavenge their food and never stop moving. While a few species migrate hundreds of meters down at dawn and then back up at dusk every day, the team found that most species aren’t quite as intrepid. The researchers also describe a new population of Allonautilus in waters off the island , one of several populations thriving due to hunting restrictions inspired in part by research efforts from this team.

For more information, contact senior author , 91̽��professor of both biology and Earth and space sciences, at argo@uw.edu.

Other 91̽��co-authors are , and . A full list of co-authors and funding is included

Green clay tennis courts become carbon negative after 10 years

The United States has around a quarter of a million tennis courts, 40,000 of which are helping mitigate greenhouse gas emissions. Green clay tennis courts, an alternative to traditional hard courts and the red clay courts popular in Europe, are constructed with a type of rock that reacts with carbon dioxide and water to sequester carbon as a stable dissolved salt. In , 91̽��researchers show that in the U.S., green clay courts remove 25,000 metric tons of carbon dioxide from the atmosphere each year and 80% of green clay courts make up for construction emissions within 10 years. Moving forward, the researchers hope to experiment with other materials that also remove carbon dioxide without compromising performance for players.

For more information contact lead author , 91̽��assistant professor of oceanography, at fjpavia@uw.edu.

A full list of co-authors and funding is available .

Temperature dynamics, not just extremes, impact heat tolerance in mussels

Intertidal mussels, forming bumpy layers on shoreline rocks, withstand significant temperature swings as the tide ebbs and flows. These creatures live in one of the most thermally variable environments on Earth, but a new study shows that the rate, timing and duration of heating and cooling impact their metabolic rate, a proxy for overall health. At the UW’s , researchers exposed mussels to temperature regimens with equal highs and lows but different patterns of change. Even when the average temperature for a set period was the same, the mussels’ response was distinct. These results, , show that predicting how marine organisms respond to climate change means considering how temperature changes over time, not just how warm it gets.

For more information, contact lead author , assistant professor of biology at the College of the Holy Cross and a mentor for the 91̽��Friday Harbor Laboratories , at mnishizaki@holycross.edu.

The other 91̽��co-author is . A full list of co-authors and funding is available .

When algae stop growing, bacteria start swarming

Tiny geometric algae, called , produce nearly a quarter of the world’s organic matter by photosynthesis. In the microscopic marine universe, diatoms coexist with both harmful and helpful bacteria. A new study, , describes how a recently identified species of marine bacteria targets diatoms based on growth phase and nutrient availability. Growing diatoms can resist bacterial attacks, but when growth ceases, the bacteria modulate their gene expression patterns to become aggressive — first swimming and releasing compounds that damage the diatom and then clustering around them to feed. Bacteria can also overcome the diatom’s defenses in nutrient-rich environments. These findings highlight the dynamic relationship between bacteria and algae in the lab. Moving forward, researchers will explore what, if anything, changes in a more complex environment.

For more information, contact lead author , 91̽��postdoctoral fellow in oceanography, at dawiener5@gmail.com.

Other 91̽��co-authors are and . A full list of co-authors and funding is available .

The 91̽�� is the best in the U.S. and No. 2 in the world for library and information management, according to the 2026 released Wednesday. Three other 91̽��subject areas placed in the top 10 in the world: geology, geophysics and Earth and marine sciences.

This ranking tracks an analysis of reputation and research output, conducted by . The consultancy looks at more than 18,300 individual university programs at more than 1,700 universities in 100 locations around the world. The ranking spans 55 academic disciplines across five broad faculty areas including arts and humanities; engineering and technology; life sciences and medicine; natural sciences; and social sciences and management.

The 91̽��has 29 programs in the top 100, 14 in the top 50, and four in the top 10, including:

• Library and information management — No. 2
• Geology — No. 8
• Geophysics — No. 9
• Earth and marine sciences — No. 10

Visit the rankings site for .

Plowing, or tilling, is an age-old agricultural practice that readies the soil for planting by turning over the top layer to expose fresh earth. The method — intended to improve water and nutrient circulation — remains popular today, but concerns about soil degradation have prompted some to return to regenerative methods that disturb the soil less.

In a new study, a team led by 91̽�� researchers examined the impact of tilling on soil moisture and water retention using methods originally designed for monitoring earthquakes. Researchers placed fiber optic cables alongside fields at an experimental farm in the United Kingdom and recorded ground motion from plots receiving different amounts of tillage and compaction from tractor tires pulling farm equipment.

The study, , shows that tilling and compaction disrupt intricate capillary networks within the soil that give it a natural sponge-like quality.

“This study offers a clear explanation for why the process of tillage, one of humanity’s oldest agricultural activities, changes the structure of soil in ways that affect how it soaks up water,” said co-author , a 91̽��professor of Earth and space sciences.

The link between tilling and soil degradation has been established for quite some time, but the rationale is less robust.

“It’s counterintuitive,” Montgomery said.

Tilling is supposed to create holes for water to reach the roots of plants, but it breaks these small channels in the soil instead, causing rain to pool on the surface and form a muddy crust. Over time, this can increase erosion and flood risk. The researchers observed this phenomenon in detail using seismological methods.

For the past decade or so, physical scientists have been exploring ways to harness the fiber optic cable network to make remote observations. They use a technique called distributed acoustic sensing, or DAS, that records ground motion based on cable strain. Because the technology is so sensitive, it can also capture the speed at which sound waves pass through a substance, which is called seismic velocity.

When soil gets wet, seismic velocity changes. Sound moves slower through mud than dry dirt.

“We wanted to find out whether seismic tools could be used to understand how soil — under different treatment regimens — would respond to environmental variability,” said senior author , a 91̽��associate professor of Earth and space sciences.

An experimental farm near Newport in the United Kingdom, affiliated with Harper Adams University, turned out to be an ideal testing ground for their experiment.

The farm is split into rows that have received consistent cultivation for more than two decades.

There are no-till rows, rows tilled 10 centimeters deep and rows tilled 25 centimeters. Compaction is a byproduct of tilling caused by tractors. Different levels of compaction were tested by modulating tractor tire pressure.

“We took advantage of a natural experiment that had already been done, but just not yet measured,” Montgomery said.

The researchers lined their experimental plots with a fiber optic cable. They collected continuous ground motion data for 40 hours and combined it with weather data over the same period, which featured light to moderate rainfall and mild temperatures.

“We observed the natural vibration of the ground and found that it is really sensitive to environmental factors, including precipitation,” said , lead author and former 91̽��postdoctoral researcher of Earth and space sciences, now at the Chinese Academy of Sciences.

They determined how each cultivation strategy impacted the soil’s response to rainfall by comparing trends in seismic velocity across study sites. Shi developed various models to process the data and help the researchers understand seismic velocity in terms of soil moisture.

The method is straightforward, inexpensive and offers far better spatial and temporal resolution than previous monitoring tools.

The researchers believe it could help farmers understand how to manage their land, provide real time flooding alerts, improve earth systems models by refining estimates of atmospheric water content and better inform seismic hazard maps with data on liquefaction risk.

Additional co-authors include , a 91̽��professor of atmospheric and climate science, , a 91̽��research assistant professor of civil and environmental engineering, from the University of California Santa Cruz, formerly at Purdue University, , , and from Harper Adams University, from the University of Exeter 

This study was funded by The Pan Family Fund, the Murdock Charitable Trust, the 91̽��College of the Environment Seed Fund, the David and Lucile Packard Foundation, and a National Environmental Research Council cross-disciplinary research capability grant.��

For more information, contact Denolle at mdenolle@uw.edu.��

The Cascadia Subduction Zone is unusually quiet for a megathrust fault. Spanning more than 600 miles from Canada to California, the fault marks the convergence of the Juan de Fuca and North American plates. While other subduction zones produce sporadic rumblings as the plates scrape past each other, Cascadia , fueling assumptions that the plates are locked together by friction.

The subduction zone — miles offshore and deep underwater — is difficult to observe. Most data collection is based onshore, which limits the breadth and quality of results. The lack of earthquakes further complicates efforts to understand its behavior and structure.

In a new study, the first to monitor strain offshore for an extended period of time, 91̽�� researchers report that the plates may not be fully locked. Based on 13 years of ground motion data from sensors in different regions, the study shows the northern portion of the fault is locked and quiet, but the central region appears to be more active. There, researchers observed signs of a shallow, slow-motion earthquake and detected pulses of fluid flowing through subterranean channels, which may relieve pressure from the fault.

The findings, , may alter expectations of how this area will respond to a large earthquake. Similar features in other places have stopped a rupture that might have otherwise continued along the entire fault line.

“It’s preliminary, but we think that variable fluid pathways in Cascadia will change the behavior of large earthquakes on the fault,” said co-author , a 91̽��associate professor of Earth and space science.

The Juan de Fuca plate is advancing toward the North American plate at a rate of . But because the plates are stuck together, that motion generates pressure. Eventually, the building tension will exceed what the plates can tolerate. When they eventually slip free, an earthquake will spread along the boundary.

Megathrust earthquakes, which occur at boundaries where one plate slides beneath another, rock the Pacific Northwest every 500 or so years. one to 1700, and estimates suggest a 10 to 15% chance that the entire fault will rupture, producing an earthquake that could exceed magnitude 9, within the next fifty years. The results from this study do not alter those odds, but the dynamics captured might influence the severity of the eventual earthquake.

A recent survey of the seafloor found that into at least four geologically distinct segments. Each one may be insulated from a rupture in another region. In this study, the researchers took a closer look at two of the regions by analyzing data from three monitoring stations, one near Vancouver Island and two off the coast of Oregon.

“We wanted to understand strain changes in different regions offshore,” said lead author , a 91̽��doctoral student of oceanography. “We used the seismometers to measure how the seismic velocity varies underneath each station.”

Seismic velocity is a term used to describe the rate at which ambient noise travels through a material. Because the speed of sound depends on what it is moving through, tracking seismic velocity can give researchers a window into processes occurring beneath the ocean floor.

“When you compact something, you can expect the sound waves to move through it faster,” said Kidiwela.

The steady increase in seismic velocity observed at the northern site told the researchers the rock was compacting, which supports the theory that the two plates are locked in place.

The central region displayed a different pattern. For two months in 2016, seismic velocity decreased. The researchers attribute this drop to a slow-motion earthquake on the shallow edge of the oceanic plate that relieved some of the pressure at the fault.

Other drops in seismic velocity, recorded between 2017 and 2022, were linked to fluid dynamics. Subduction squeezes liquid out of rocks and pushes it toward the surface. The study found that other faults, running perpendicular to the subduction zone, may act as pathways for letting trapped fluid out.

“During a megathrust rupture, one of the ways that an earthquake propagates is through fluid pressure. If you have a way to release these fluids, it could help improve the stability of the fault, and potentially impact how the region behaves during a large earthquake,” Kidiwela said.

Pulling data from just three sites, the researchers observed complex dynamics that may have gone overlooked. Future work will greatly expand this effort. in 2023 to build an underwater observatory in the Cascadia Subduction Zone.

“Finding this link between fluids coming to the shallow subduction zone is pretty unique, as is the evidence that the fault is not completely locked,” said co-author , a 91̽��professor of oceanography and one of the scientists involved with the observatory. “It suggests that we need more instruments there, because there may be more going on than people have been able to figure out before.”

Additional co-authors include from the University of Utah.��

This study was funded by the Jerome M. Paros Endowed Chair in Sensor Networks at the 91̽�� and the National Science Foundation.��

For more information, contact Kidiwela at seismic@uw.edu.

The American Geophysical Union honored five 91̽�� faculty and researchers from the Earth and space sciences and atmospheric and climate science departments this week at the annual meeting in New Orleans.

Each year, the meeting draws thousands of scientists, educators and policymakers to discover emerging research, discuss hurdles and network. Prior to the meeting, AGU announces awards for individuals who have made significant contributions to Earth and space science and presents them in person during the week.

The theme is, “Where Science Connects Us,” and the 91̽��awardees were recognized for research that advances understanding of natural hazards, the history of Earth, weather and climate change.

Here are the UW’s five recipients and their respective awards:

, a 91̽��assistant professor of Earth and space sciences, studies how magmas form beneath volcanoes. She specializes in work that involves using samples from past volcanic eruptions to examine the behavior of volcanic gases like water, carbon, and sulfur, which can help researchers monitor active volcanoes. Muth received the for early career scientists who have made outstanding contributions to fields of volcanology, geochemistry, and petrology.

, a 91̽��professor of atmospheric and climate science, studies predictability, mountain meteorology and numerical weather prediction. Durran’s recent research focuses on using deep learning to change our current paradigm for numerical weather prediction, seasonal forecasting and climate modeling. He holds a joint position with NVIDIA. Durran received the award for prominent scientists who have made exceptional contributions to the understanding of weather and climate.

, a 91̽��postdoctoral researcher of atmospheric and climate science, studies the formation and evolution of aerosol particles in the atmosphere, which play a pivotal role in both air pollution and climate change. By identifying and characterizing the fundamental chemical processes governing aerosol behavior, his research supports efforts to predict current atmospheric conditions and the trajectory of air quality and climate moving forward. Kenseth received the recognizing outstanding science and accomplishments by researchers that are within three years of receiving their doctorate.

, a 91̽��assistant professor of Earth and space sciences, uses simulations to study the interactions between planetary atmospheres, interiors and biospheres to better understand the long-term evolution of Earth, Venus and rocky exoplanets. By building a holistic understanding of planetary evolution, this work will help enable scientists to search for life on other planets. Krissansen-Totton received the recognizing significant contributions to planetary science by early career researchers

, a 91̽��professor of Earth and space sciences, studies the ratio of elements and their isotopes in rocks and minerals to understand how planets form and evolve. His research introduced a new method for analysis involving isotopic “fingerprints” that allows scientists to learn about Earth’s crust, the composition of the mantle, the origins of magma and even the early solar system. Teng was inducted as a , a program that recognizes AGU members who have made exceptional contributions to Earth and space science through a breakthrough, discovery or innovation in their field.

Careful reanalysis of data from more than a decade ago indicates that Saturn’s biggest moon, Titan, does not have a vast ocean beneath its icy surface, . Instead, a journey below the frozen exterior likely involves more ice giving way to slushy tunnels and pockets of meltwater near the rocky core.

Data from NASA’s to Saturn initially led researchers to suspect a large ocean composed of liquid water under the ice on Titan. However, when they modeled the moon with an ocean, the results didn’t match the physical properties described by the data. A fresh look yielded new — slushier — results. The findings could spark similar inquiries into other worlds in the solar system and help narrow the search for life on Titan.

“Instead of an open ocean like we have here on Earth, we’re probably looking at something more like Arctic sea ice or aquifers, which has implications for what type of life we might find, but also the availability of nutrients, energy and so on,” said , a 91̽�� assistant professor of Earth and space sciences.

The study, , was led by NASA with collaboration from Journaux and , a 91̽��graduate student of Earth and space sciences in his lab.

The Cassini mission, which began in 1997 and lasted nearly 20 years, produced volumes of data about Saturn and its 274 moons. — shrouded by a hazy atmosphere — is the only world, apart from Earth, known to have liquid on its surface. Temperatures hover around -297 degrees Fahrenheit. Instead of water, liquid methane forms lakes and falls as rain.

As Titan circled Saturn in an elliptical orbit, the researchers observed the moon stretching and smushing depending on where it was in relation to Saturn. In 2008, they proposed that Titan must possess a huge ocean beneath the surface to allow such significant deformation.

“The degree of deformation depends on Titan’s interior structure. A deep ocean would permit the crust to flex more under Saturn’s gravitational pull, but if Titan were entirely frozen, it wouldn’t deform as much,” Journaux said. “The deformation we detected during the initial analysis of the Cassini mission data could have been compatible with a global ocean, but now we know that isn’t the full story.”

In this study, the researchers introduce a new level of subtlety: timing. Titan’s shape shifting lags about 15 hours behind the peak of Saturn’s gravitational pull. Like a spoon stirring honey, it takes more energy to move a thick, viscous substance than liquid water. Measuring the delay told scientists how much energy it takes to change Titan’s shape, allowing them to make inferences about the viscosity of the interior.

The amount of energy lost, or dissipated, in Titan was much greater than the researchers expected to see in the global ocean scenario.

“Nobody was expecting very strong energy dissipation inside Titan. That was the smoking gun indicating that Titan’s interior is different from what was inferred from previous analyses,” said , a postdoctoral fellow at NASA’s Jet Propulsion Laboratory, who led the study.

The model they propose instead features more slush and quite a bit less liquid water. Slush is thick enough to explain the lag but still contains water, enabling Titan to morph when tugged.

Petricca arrived at this conclusion by measuring the frequency of radio waves coming from the Cassini spacecraft during Titan fly-bys, and Journaux helped ground the results with thermodynamics. Journaux studies water and minerals under extreme pressure to gauge the potential for life on other planets.

“The watery layer on Titan is so thick, the pressure is so immense, that the physics of water changes. Water and ice behave in a different way than sea water here on Earth,” Journaux said.

His has spent years developing the methods to simulate extraterrestrial environments in the lab. He was able to provide Petricca and colleagues with a dataset describing the anticipated physical properties of water and ice deep inside Titan.

“We could help them determine what gravitational signal they should expect to see based on the experiments made here at UW,” Journaux said. “It was very rewarding.”

“The discovery of a slushy layer on Titan also has exciting implications for the search for life beyond our solar system,” Jones said. “It expands the range of environments we might consider habitable.”

Although the notion of an ocean on Titan invigorated the search for life there, the researchers believe the new findings might improve the odds of finding it. Analyses indicate that the pockets of freshwater on Titan could reach 68 degrees Fahrenheit. Any available nutrients would be more concentrated in a small volume of water, compared to an open ocean, which could facilitate the growth of simple organisms.

While it is unlikely that the researchers discover fish wriggling through slushy channels, if life is found on Titan, it may resemble polar ecosystems on Earth.

Journaux is on the team for to Titan, scheduled for launch in 2028. The data collected here will guide the mission and Journaux hopes to return with some evidence of life on the planet and a definitive answer about the ocean.

Co-authors include , , , , , and from NASA; at Southwest Research Institute; and from the University of Nantes; from the University of Bologna; from the California Institute of Technology and from Sapienza University of Rome.

This research was funded by NASA, the Swiss National Science Foundation and the Italian Space Agency.��

For more information, contact Journaux at bjournau@uw.edu or Petricca at flavio.petricca@jpl.nasa.gov.�� 

This story was adapted from .

Approximately 400,000 years ago, some areas of Greenland that are now covered by a thick layer of ice were exposed to fresh air and sunlight. Today, the covers most of the land mass, but the southwestern coastline is ice-free. Back then, the northwest was too.

come from sediment and ice samples collected in the 1960s. They were all but forgotten until 2019, when an international team of scientists embarked on a collaborative effort to understand modern climate change by tracking climate over longer periods of time.

The process is captured in “,” a documentary film that debuted on streaming services such as YouTube, Apple TV and Amazon Prime this fall. Director , a former evolutionary biologist, travelled to labs around the world — including at the 91̽�� — to interview and film scientists as they deciphered clues about the past from old ice and sediment samples.

These samples were collected during the Cold War at a U.S. military base in Greenland. — established in 1959, about 150 miles inland and just below the surface of the ice — was used by the U.S. to conduct military operations in secret, and do science on the side. Before Camp Century was abandoned in 1967, the team drilled more than 1,000 meters through the entire ice sheet and into the sediment below.

, a 91̽��professor of Earth and space sciences, is among those featured in Kasic’s film. Steig spoke with 91̽��News about the backstory.

How did the project begin? What was your role?

Eric Steig: I was working with a team of researchers led by at the University of Vermont to develop a plan for analyzing these old sediment and ice samples. We were gathering an international consortium of experts when I ran into Kathy at a scientific meeting and invited her to join us. I had seen her previous work about Antarctica and thought it was fantastic.. Because Kathy was involved early on, she was able to go to all these different labs and see the science unfold in real time.

What did your lab contribute to the research effort?

ES: My lab studies isotopes, which are the different versions of elements. We measure the concentration of heavy and light oxygen and hydrogen in little pockets of water preserved in the sediment. The ratios of those water-isotope concentrations tell us how temperatures have changed. We also analyzed isotopes of carbon and nitrogen, which reflect shifting ecological conditions in the ancient soil.

At the same time, our European colleagues were measuring the ice just above the soil, and we were working together to understand what happened at this transition point. We’re using this combination of ecology, chemistry, water and plants to disentangle what the climate was like in more detail. A lot of the work has been published, but some is still underway.

What has the project accomplished thus far?

ES: It gives us this beautiful window into history that we can use to learn about ice-free conditions. For example, we know there was an extended warm period around 400,000 years ago, from modeling, but now we can also see that reflected in the sediments. It might not have been that much warmer than it is today, but it was warm for a very long time.

There’s plenty of evidence now that the Greenland ice sheet is melting and at some point it will be gone. Our research advances our understanding of the ice sheet and it will help us refine the ice-sheet models used to predict sea level rise.

Why did the researchers collect these samples in 1960? Why can’t we get more?

ES: At the time, scientists understood the value of water isotopes and their relevance to climate. They observed this clear relationship between temperature and isotope composition that could capture climate though time, but they weren’t thinking about global warming.

Fast forward a few decades and these historic samples have immense value in climate science, especially with the advent of modern analytical tools. Those of us who study Greenland would love to put holes in a lot of places to map out exactly how the ice evolved, but drilling is expensive and time consuming. Ice cores are one thing, but sediment and bedrock present new challenges. There have only been a small handful of successful attempts to drill through the ice and sample what is beneath it.

What do you think this film helps to convey?

ES: As a scientific community, we spent decades studying what Earth was like with more ice. I grew up in this era where the questions were about the ice ages. That’s no longer the most pressing question. We need to be asking what the Earth was like when there was less ice, because that is where we are heading. The film captures this shift from studying cold periods to studying warm ones.

For more information, contact Steig at steig@uw.edu.

Sometime between 1381 and 1391, an earthquake exceeding magnitude 8.0 rocked the northeastern Caribbean and sent a tsunami barreling toward the island of Anegada.

, depositing coral boulders hundreds of meters inland. The corals died but their skeletons remain. More than six centuries later, scientists are learning that these skeletons hold clues about tsunami history. showed the flooding likely resulted from a tsunami generated during a large earthquake in the nearby Puerto Rico Trench.

Now, in an open-access paper , researchers narrow the tsunami time frame to the last decades of the 14th century. The researchers expect this finding to support ongoing .

“If you’re designing a school or a hospital near the coast, you want to know whether there’s a chance that a very big earthquake could occur, and you want to design that building to withstand it,” said corresponding author , a 91̽�� affiliate professor of Earth and space sciences and research geologist with the United States Geological Survey.

Anegada is the northernmost of the British Virgin Islands, sitting just south of the , where the Caribbean and North American plates converge. Most of the islands are protected by a broad, shallow continental shelf. Waves lose energy as they roll across the expanse, decreasing the chances of a tsunami hitting Caribbean shores. Anegada is different — the seafloor slopes steeply toward the deep trench, making the island more hazard prone.

Written records from the northeastern Caribbean go back five centuries, but none provide evidence for a tsunami from the Puerto Rico Trench. Geology allowed the researchers to evaluate tsunami history on a longer timescale.

Researchers began surveying the region after a massive earthquake and tsunami struck the Indian Ocean in 2004, .

The disaster surprised everyone, including researchers, prompting officials in the U.S. to on the Atlantic seaboard. , one of the project leads and a research geophysicist at Woods Hole Coastal and Marine Science Center, asked Atwater to check for signs of similar activity on Anegada. Atwater spent years in Indonesia after the tsunami.

The evidence uncovered on Anegada drew various research teams to the island and produced a series of discoveries.

In the most recent study, led by , an associate research professor at the University of Maryland Center for Environmental Science, the researchers present a time frame for the medieval tsunami based on how old the coral was when it died.

They calculated age by measuring two radioactive elements — uranium and thorium — that decay at known rates. These measurements were made on samples from the inside of the coral skeletons, due to weathering and potential contamination. The researchers then added the number of annual growth bands between the dated sample and the exterior of the coral to estimate when the tsunami occurred.

“Corals have annual density bands, much like tree rings,” Kilbourne said. “We were able to count how many years passed between the top density bands and the sections we used for dating.”

Kilbourne can also gather valuable environmental data from the coral skeletons, which store information about temperature and salinity, and plans to continue studying the samples to better understand climate change over longer timescales.

For more information, contact Atwater at atwater@uw.edu or Kilbourne at kilbourn@umces.edu.

Additional co-authors include and at Paris Institute of Earth Physics; at Aix-Marseille University; at the University of Delaware; at National Taiwan University and at Colorado Mesa University and the United States Geological Survey.��

This research was funded by the U.S. National Science Foundation, the University of Paris-IPGP, the French National Research Agency, Academica Sinica, the Higher Education Sprout Project of the Taiwan Ministry of Education, the National Taiwan University Core Consortiums Project, the Taiwan National Science and Technology Council.

The Cassini space probe ended its mission in 2017 with a dramatic plunge into Saturn, yet it continues to fuel discoveries.

In a new analysis of data from one of the probe’s instruments, an international team of researchers has identified new organic compounds within jets of icy water erupting from Saturn’s moon, Enceladus. The material likely originated in Enceladus’ ocean, and adds to mounting evidence that the moon could be habitable.

“We found a rich organic inventory in Enceladus’ plume,” said Fabian Klenner, a 91̽�� postdoctoral researcher of Earth and space sciences and a member of the research team. “Having clear evidence of a variety of organic compounds from inside an extraterrestrial water world is incredible and further strengthens Enceladus’ potential for habitability. It appears that Enceladus has all the ingredients for life as we know it.”

in Nature Astronomy.

Launched in 1997, Cassini performed a while in orbit around Saturn, resolving two longstanding mysteries surrounding the system: the origin of Saturn’s enormous but faint E ring and the cause of Enceladus’ unusual brightness. Enceladus, it turns out, is covered in a 16-19 miles thick shell of highly reflective ice which hides a global saltwater ocean. The probe observed fissures in the ice of the moon’s South Polar Terrain ejecting massive quantities of icy water into space. Some of the material forms Saturn’s E ring.

Data from Cassini’s Cosmic Dust Analyzer, or CDA, previously helped researchers identify organic compounds and other key building blocks for life within Saturn’s E ring. Cassini also found material in the E ring that suggests hydrothermal activity deep within Enceladus.

“We suspect that so-called hydrothermal fields exist there — these are vents at the bottom of the ocean from which hot water rises. There is evidence that life on Earth originated in such fields,” said lead author , a research group leader at Freie Universität Berlin.

The new results come from data collected in a close flyby of Enceladus’ icy plume, offering scientists a look at material that had been inside the moon just minutes before.

“The high-speed flyby of Enceladus enabled us to identify new compounds that were not found in the E ring data, most notably esters, alkenes and ether compounds,” said Klenner, who helped validate the new CDA results. “Notably, esters and ethers can be part of lipids, and lipids are key to life as we know it.”

The success of Cassini has helped stoke considerable investment in future missions to the outer solar system. NASA’s is currently en route to Jupiter to study its moon Europa, which is also a promising candidate in the search for extraterrestrial life.

In the meantime, there’s plenty more Cassini data up for grabs.

“It’s phenomenal to continue learning from the Cassini mission,” said Klenner, who will start a new position as an assistant professor at the University of California, Riverside in December. “Much of the CDA data still isn’t analyzed and I’m so excited about what it may reveal next.”

Co-authors include , , , and at Freie Universität Berlin; at the University of Colorado, Boulder; and at the Institute of Science Tokyo; and and at the University of Stuttgart.��

This research was funded by the European Research Council, the German Aerospace Center, the state of Berlin and NASA.

For more information, contact Klenner at fklenner@uw.edu.��

This story was adapted by the University of Stuttgart.