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In our Solar System, there are numerous mean-motion resonances for the minor bodies and satellites, but there are no mean-motion resonances between the planets. The first mean-motion resonance in an extrasolar planetary system – the 2:1 resonance between two Jupiter-mass planets around the star GJ 876 – was discovered in 2001. Since then, an increasing number of pairs of planets in or near mean-motion resonances and resonant chains of three or more planets have been detected. I will discuss the dynamics of these systems and the constraints that they provide on the formation and dynamical evolution of planets. Topics will include high-order mean-motion resonances in the HD 202206 and nu Ophiuchi systems and the formation of resonant chains near the inner edge of protoplanetary disks.

 Venus, Earth’s twin, is not only the closest planet to us in the solar system, it the closest to Earth in mass, density and size and yet it evolved very differently than the Earth. Venus has an atmosphere that has 90 times the surface pressure as the Earth with a surface temperature of 460 C. Venus does not have a system of plate tectonics like the Earth which is one of the key reasons that Earth is a habitable planet. So how did two planets with roughly the same physical parameters evolve so differently? The NASA Magellan mission to Venus in the Early 1990’s used radar to image the planet’s surface through the optically opaque atmosphere at ~150 m resolution and showed that Venus has a young surface that had been volcanically resurfaced with the last 500 million years. As much a Magellan informed us about Venus it also left many key questions about Venus’s planetary evolution unanswered. Two missions to Venus, VERITAS by NASA, and EnVision by ESA in partnership with NASA, will return to Venus in the 2030’s with the goal of answering how these planet’s evolved so differently. The answer to this question will help inform how many Earth and Venus like planets are there in other solar systems. Radars play a key role on each mission and this talk will describe their role in these missions to Venus and how in combination with the other instruments hope to resolve one of the key mysteries in planetary science.  

Our knowledge of the satellite population in the solar system has grown rapidly in the past 100 years.
In the early 1900s almost every known moon was a regular satellite — the large, primordial bodies that formed with their parent planets.
The Voyager flybys fundamentally changed that picture by revealing numerous small inner satellites of the giant planets, bodies likely tied
to ring-system evolution and ongoing collisional processing near the planet. Beginning around 2000, wide-field CCD surveys (e.g. CFHT, Subaru) opened a third population regime: most new discoveries were irregular or outer satellites — dynamically distinct, highly inclined, often retrograde
objects whose origins are not native to the planet system but are best explained as captured heliocentric planetesimals from the early solar system. At JPL, we develop and maintain ephemerides for all known satellites. The orbital models range from simple precessing ellipses to full dynamical models that include tides, relativistic terms, satellite libration, and high order gravity field expansions. These models draw on data sets spanning more than a century of astrometric measurements, from early visual observations to modern spacecraft tracking. Ultimately, satellite ephemerides are not just navigation products needed to point a telescope or fly a spacecraft – they are scientific observables that encode the history and dynamics of entire planetary systems. Each orbit tells a story about its origin, its interactions, and its ongoing evolution.
We will review the current state of satellite ephemerides across the solar system and highlight some interesting dynamical puzzles.

Being able to image the ruptures of moderate earthquakes would significantly increase our observations towards comprehending earthquake source physics, fault properties and seismic hazards.

However, resolving their rupture characteristics remains challenging for conventional seismic networks due to limited station density. The emergence of Distributed Acoustic Sensing (DAS) offers a potential solution by providing dense and continuous measurements. In this study, we systematically evaluate the resolution capabilities of multi-fibre DAS networks for back-projection (BP) and demonstrate the feasibility of using DAS networks through both synthetic tests and analysis of a Mw 4.9 event in the Eastern California Shear Zone.

Furthermore, we propose a two-step inversion procedure that strategically integrates DAS with the conventional network. Our results suggest that strategically deployed multi-fibre DAS network can serve as the next generation of earthquake observation system and significantly enhance our understanding of earthquake rupture physics, as well as seismic risk preparedness.

Numerical simulations of seismic wave propagation are crucial for investigating velocity structures and improving seismic hazard assessment. However, standard methods such as finite difference or finite element are computationally expensive. Recent studies have shown that a new class of machine learning models, called neural operators, can solve the elastodynamic wave equation orders of magnitude faster than conventional methods. Full waveform inversion is a prime beneficiary of the accelerated simulations. Neural operators, as end‐to‐end differentiable operators, combined with automatic differentiation, provide an alternative approach to the adjoint‐state method. State‐of‐the‐art optimization techniques built into PyTorch provide neural operators with greater flexibility to improve the optimization dynamics of full waveform inversion, thereby mitigating cycle‐skipping problems. We demonstrate the application of neural operators for full waveform inversion on real seismic data, using nodal transects collected across the San Gabriel, Chino, and San Bernardino basins in the Los Angeles metropolitan area. 

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Magnetopause magnetic reconnection during periods of northward interplanetary magnetic field (IMF) plays a key role in the entry of solar wind mass into the magnetosphere. The effects of reconnection can be observed in the low-altitude cusp, and the new NASA TRACERS mission is designed for this purpose. I will present a TRACERS-THEMIS conjunction near the peak of a geomagnetic storm after the IMF had turned northward. In the low-altitude cusp, TRACERS observed signatures consistent with lobe reconnection poleward of the cusp, including reversed ion dispersions and sunward convection. Concurrent THEMIS observations at the low-latitude magnetopause reveal the presence of a magnetosheath boundary layer (MSBL) and capture of magnetosheath plasma on magnetospheric field lines, both consistent with poleward-of-cusp reconnection. Global simulations of the event show that poleward-of-cusp reconnection was adding magnetic fields and plasma to the magnetosphere, and in the process moving the cusp poleward. The event also illustrates how the magnetosphere and cusp recover when the IMF turns northward after a storm has eroded the magnetopause inward and moved the cusp equatorward.

Jupiter’s moon Europa is a key target in the search for extraterrestrial life, but assessing its habitability via magnetic induction requires a well-grounded understanding of the plasma environment. At Europa, this task relies on magnetohydrodynamic (MHD) models that have been developed over many years. While powerful, these models are computationally expensive, with some codes requiring > 12 hours on a 2,000-core machine. Fitting spacecraft observations to MHD models demands many runs, resulting in a potentially days- or weeks-long process. This presents a major bottleneck for missions such as Europa Clipper and JUICE, potentially limiting their scientific return.
In this talk, I introduce a transformer-based surrogate for a state-of-the-art MHD model used to help characterize Europa’s subsurface ocean. The surrogate evaluates in milliseconds on a laptop rather than hours on a supercomputer, achieving a speed-up of approximately 40,000x while delivering high-fidelity, uncertainty-aware magnetic field predictions. This acceleration enables three new scientific pathways that are feasible with MHD alone: large-scale parameter surveys, simulation-based inference, and feature-importance analysis. These analyses are important as the environment is poorly constrained observationally. Overall, this approach represents a paradigm shift in the investigation of space plasmas and opens the door to a host of novel science investigations.

NASA science missions are often complex systems of systems, involving various stakeholders, including the United States’ Congress. To ensure a clear and concise communication of expectations, requirements, and constraints, NASA has adopted the Science Traceability Matrix (STM). STM provides a logical flow from the decadal survey to science goals and objectives, mission and instrument requirements, and data products. STM serves as a summary of what science will be achieved and how it will be achieved, with a clear definition of what mission success will look like. In this seminar, I will present the STM from the Parker Solar Probe (PSP), including requirements relating to the plasma instrument for which I am a co-investigator. I will describe how our team used the STM to map the mission’s top-level requirements to mission success criteria and helped to eliminate any single point of failure that could end the mission prematurely. I will then present my own research on magnetic switchbacks in the PSP magnetic and plasma observations and their role in solar wind acceleration and heating. I will conclude the seminar by discussing how my research on the temporal evolution of switchbacks in the solar wind led to a new STM, and helped to chart a multidisciplinary path to designing a ground-breaking science mission concept, titled Space Weather Investigation Frontier (SWIFT), with the potential to improve space weather forecasting lead times by up to 40%.

Extraterrestrial EM induction was first carried out in the 1970s
by forming magnetic transfer functions for the Moon as the ratio of
magnetic fields observed at the surface (Apollo 12) to those observed in
distant orbit (Explorer 35). In March 2025, a similar analysis was
performed using the Lunar Magnetotelluric Sounder (LMS) on Blue Ghost
Mission 1 and the ARTEMIS spacecraft. In spite of nearly 90 deg arc
distance between these surface locations, the derived subsurface
conductivities are very similar. This sharply limits contemporary
temperatures under the western nearside of the Moon in spite of its past
history of widespread volcanism. The two-week surface mission recorded
surface electric and magnetic fields in the solar wind, magnetosheath, and
magnetotail, including an eclipse and sunset. Plasma properties correlate
well with ARTEMIS.

Mars’ lack of a global magnetic field led to low expectations for auroral phenomena on the planet, but MAVEN and Emirates Mars Mission observations have unexpectedly shown auroral activity to quite diverse in nature, dynamically varying and often global in scope. The image below shows three fundamentally different types of aurora on Mars. Ironically, Mars’ lack of a global field is actually responsible for most of the activity, which leads to a new perspective for non-magnetized objects in our solar system and beyond. Each of the three types of aurora is a tracer of a different important process involving the interaction between solar influences and the near-Mars magnetic and charged particle environment. The seminar will describe observations by MAVEN’s Imaging UltraViolet Spectrograph (IUVS) and the Emirates Mars UltraViolet Spectrometer (EMUS) and highlight the new insights they offer.

Space weather is the “weather” of the space environment driven by our active Sun—solar eruptions and changing solar wind conditions that can disturb Earth’s magnetic field and upper atmosphere, disrupt satellites and communications, degrade navigation and timing, increase radiation risk to astronauts, and induce electrical currents in long conductors on the ground. Over the past decade, U.S. preparedness for major space weather events has changed in two consequential ways: (1) the power sector began translating scientific risk into enforceable reliability practice when the Federal Energy Regulatory Commission (FERC) directed the North American Electric Reliability Corporation (NERC) to develop Reliability Standards to mitigate geomagnetic disturbance (GMD) impacts on the Bulk-Power System ; and (2) the United States adopted a coordinated, whole-of-government posture through the National Space Weather Strategy and Action Plan—now further advanced through a more recent federal implementation plan that builds on the 2015 foundation .

I will highlight key scientific and operational developments from the last few years, including NASA’s Space Weather Program role in advancing space weather observations, models, and applications that support prediction and tracking across the solar system. A central case study will be the May 2024 geomagnetic storm—first G5 (“severe”) storm in over two decades—now commonly referred to as the “Gannon storm,” and what it revealed about magnetosphere–ionosphere coupling, satellite impacts, and the pathways to societal consequences.

Finally, I will offer focused perspectives on high-impact risk areas—especially electric power grids—connecting space physics to practical resilience: where the key areas of uncertainty are, what “good enough” information looks like for operations, and how research, standards, and planning can converge to reduce national risk before the next extreme event.

Learn about ionizing radiation in the final frontier from UCLA Space Medicine Program Director Dr. Haig Aintablian and Radiation Oncology resident Dr. Nic Nelson. They will share a brief overview of modern space medicine and basic radiobiology before exploring the space radiation environment with its unique risks to astronaut health. They will then illustrate how researchers and mission planners are preparing for the next phase of human space exploration—interplanetary travel—by investigating different physical and biological countermeasures and applications in personalized medicine.

Solar radio bursts are signatures of nonthermal electron acceleration by energetic events such as flares and coronal mass ejections. The launches of Parker Solar Probe in 2018 and Solar Orbiter in 2020 have enabled new views of radio bursts from the vantage point of the inner heliosphere. In this talk, I will briefly discuss some of the top radio burst discoveries of the Parker-Orbiter era, with a focus on circular polarization observations made by Parker Solar Probe. I will describe the measurement of polarization using spacecraft antennas, show examples of circularly polarized Type II and Type III radio bursts, and discuss how polarization can serve as a remote diagnostic of radio burst source regions.

Galileo, Cassini and Juno space missions have provided much data on gas giant magnetospheres. Here we examine the important commonalities of the two systems that also characterise the differences to the plasma environment of the inner planets. Both systems are fast rotators and have internal sources of magnetospheric material deep within the system. The internal sources means there must be a system for transport of material outward. Commonly, marginally stable interchange motions of flux tubes are invoked to provide diffusion on relatively small scales transverse to the field. This no doubt occurs near the source but processes like self-organisation may lead to more ordered motion at larger distances. A large distinction between Jupiter and Saturn systems is that the jovian planetary magnetic field is far from axially symmetric with respect to the planetary rotation axis whereas Saturn’s field is close to axially symmetric. However, despite this, the Saturn system does exhibit variable periodicities in plasma, radio, aurora and the external magnetic field around 10.7 hours. The external magnetic source was a surprise; the ubiquitous Saturn oscillations are still described as “mysterious”. No similar oscillations are recorded at Jupiter. We shall aim to remove some of the mystery and suggest that the dynamical effect of rotation has not been fully appreciated in either system.

Prediction serves as the ultimate test of our scientific understanding of geophysical systems. Accurate forecasting of near-Earth space environmental conditions is critical to radio communication, navigation, and space traffic management. Effective numerical prediction of the region’s conditions allows us to better protect important space assets and related systems in the event of natural hazards. My research group aims to advance the science and engineering of forecasting, as applied to the Earth’s atmosphere extending from the ground to geospace. Prediction of the constantly changing near-Earth space environmental conditions – affected by both space and terrestrial weather – is inherently challenging. Data assimilation provides a systematic approach to integrating observations with first-principles models, extending the predictive capability of numerical models by reducing uncertainties in drivers and preconditions and constraining model dynamics with observations. The data assimilation and ensemble-based probabilistic modeling framework can also be applied to the design of future missions and the targeting of observations to maximize scientific returns of observing systems. This seminar showcases some of the latest data assimilation research and outlines future plans, setting the stage a discussion on how we can work together to advance the next generation of predictive modeling and observational strategies.

The dynamics of glaciers and ice sheets influence rates of sea-level rise, freshwater supplies, and landscape evolution. Decades of research has highlighted key processes and connections between terrestrial ice, the climate, and the solid earth, but limited observations have allowed fundamental questions in glaciers dynamics to remain open. In this talk, we will explore some related questions: What is the viscosity of glacier ice and how does it depend on stress? Why does ice fracture? Building on these fundamental questions, we will highlight new efforts to support polar science and accelerate improvements in our ability to observe and model ice sheets. 

In this talk I am going to explore the interplay between tectonic and surface processes in shaping Cordilleran-type orogenic systems, having the Central Andes as the main study case. The Escoipe Canyon in NW Argentina cross cuts the fold-and-thrust belt of the Eastern Cordillera, which makes the transition from the Puna Plateau to the modern foreland region. A new dataset of multiple low-temperature thermochronometers records the history of orogenic building from rifting to foreland basin, and ultimately the thrust belt forming the present-day orographic barrier of the Central Andes. The apatite (U-Th)/He data, however, dates the last 10 myr of history after the main episode of shortening, and shows a westward trend of younger cooling ages, opposite to the regional cooling trend in the thrust belt. I will explore a hypothesis regarding climate and surface processes controlling rock exhumation in the canyon, and the impacts on orogenic evolution. Additionally to this data-driven study case, I will show some effects of orography in Cordilleran-type systems in the lithospheric scale using geodynamic models, and demonstrate that surface processes might affect strain distribution and lithospheric removal processes.

Climate change is stressing the American West’s century-old system of water storage and conveyance, through longer and more intense droughts and periods of exceptional rainfall and flooding. Nowhere are these challenges more acute than in California’s Central Valley, which produces 25% of the USA’s agricultural output on climatologically marginal farmland. Intense management of mountain discharge into the Central Valley, along with oversubscribed rights to surface water, have resulted in unchecked exploitation of the Valley’s groundwater resources and impeded initiatives to use occasional surface water surpluses for aquifer recharge.

New regulation has sparked interest in better information on groundwater availability. Here at Scripps, our lab uses remotely sensed observations of Earth’s gravity and surface motion to infer the dynamics of the hydrological system that feeds the Central Valley aquifer. These techniques track the evolution of mountain water storage at various timescales, and they reveal how this stored water enters and flows through the Central Valley aquifer. Effective management of groundwater resources in the Central Valley will require adoption of data-informed policies, and our hope is that our insights into Central Valley hydrology will prove useful to this end.

50+ years after the Apollo missions, NASA will be sending astronauts back to the Moon. This time, the astronauts will land near the South Pole of the Moon. The Lunar Environment Monitoring Station (LEMS-A3) is one of the selected Artemis III Deployed Instruments. LEMS-A3 is built to operate independently of the Artemis III crew spacecraft, survive the lunar night and operate for at least two years. The LEMS-A3 payload is a set of astronaut-deployed seismometers, SeisLEMS, consisting of a broadband (BB) and short period (SP) instrument built by the University of Arizona and Silicon Audio Inc. Artemis astronauts will deploy and position LEMS-A3, and bury the BB and SP instruments into an astronaut dug-trench and borehole, respectively.
The BB and SP will continuously record ground motions at 100 samples per second (sps) and relay 15 sps data back to Earth once a month. The LEMS team will use the ground motions to detect and locate lunar seismic events including impact-driven, shallow, and deep moonquakes and iteratively backfill the events with 100 sps data. The proposed Artemis III landing sites all enable seismic surveys of the southern pole and farside of the Moon; geographic regions that have previously be unexplored with seismometers. Through seismic data interpretation we aim to catalog seismicity of the Moon, investigate the crustal and mantle structure of the south pole, determine the structure of the deep interior, and ascertain seismic hazards.
Although LEMS-A3 is designed as a stand-alone seismic station, it is possible that it may operate at the same time as other seismometers, e.g. the Farside Seismic Suite (FSS) and other future lunar missions equipped with seismometers. If FSS and LEMS-A3 are operational at the same time, more science may be accomplished through collaboration of the science teams and shared datasets.

The modern world teems with complex life—the animals, plants, fungi, seaweeds, and a dazzling array of single-celled organisms known as the protists. All of these are part of the eukaryotic clade, descended from a common ancestor that lived more than 1 billion years ago. In this talk, I will provide an overview of early eukaryote evolution and the environmental context in which they evolved.  I will present new research that sheds light on the habitats in which eukaryotes lived and how they might have survived the extreme “snowball Earth” glaciations that entombed the planet in ice 720–635 million years ago (Ma). Finally, I will highlight the outstanding questions that remain, including what drove their rise to dominance during the late Neoproterozoic Era (~600 Ma).

Statically stable density stratification is ubiquitous in geophysical flows. It tends to suppress vertical motions, leading to thin, sheared layers and highly anisotropic structures. This talk discusses recent progress in understanding stratified turbulence, including mixing efficiency and the role of intermittent events, and highlights open questions relevant to oceans and atmospheres.

Juno and Cassini have revealed that Jupiter and Saturn likely contain broad regions where heavy elements are mixed gradually, rather than being sharply separated. A major open question is how these composition gradients can survive for billions of years, even though the planets’ interiors are vigorously convecting.

In this talk, I’ll present numerical simulations that explore how convection mixes compositional gradients in a simplified model of a planet’s interior. I’ll show that rotation can play an important role in shaping the flow and can strongly influence how efficiently composition is mixed. Also, I will show that under certain conditions, the combined effects of temperature and composition cause the fluid to organize itself into stacked convective layers, remarkably similar to the layers that form in a latte. I’ll conclude by discussing the challenges for our understanding of convective mixing and what this means for giant planet interiors.

Planets exhibit extraordinary diversity in physical properties and orbital architectures, spanning more than four orders of magnitude in mass, separation, and age. Interpreting this landscape is challenging as observational biases and orbital migration obscure the pathways of planet formation and evolution across both space and time. While the full picture remains incomplete, a story is emerging for gas giants from radial velocity surveys probing planetary systems from the inside out and high-contrast imaging from the outside in. These complementary approaches are converging at intermediate scales, enabling a more continuous view of giant planet populations. I will present results from recent ground- and space-based efforts to constrain how giant planets assemble and evolve, focusing on accretion disks, population demographics, orbital eccentricities, and stellar spin–orbit misalignments. Together, these are informing the processes of gas accretion, angular momentum exchange, and dynamical evolution that shape planetary systems. I will also highlight how upcoming astrometric discoveries from Gaia—which is expected to reveal thousands of giant planets at intermediate separations later this year—will help bridge the gap between inner and outer planet populations and clarify how giant planets form and interact over time.

In its travel through the Milky Way, the Sun traverses a variety of Galactic
environments, including dense interstellar clouds. Astronomical effects on
Earth’s past climate have been limited to 10,000-year scales variations in
Earth’s orbital parameters while our recent studies suggest that
longer-term climate shifts that occur every few million year may be linked
to compression of the heliosphere (the “cocoon” formed by the solar wind)
when the Sun crosses dense clouds as it travels through the Milky Way.
During such periods Earth was exposed to increased radiation and large
amounts of hydrogen, potentially altering its climate. These events are
consistent with independent 60Fe records indicating nearby astrophysical
encounters at ~2–3 and ~6–7 million years ago (Ma), as well as 10Be
anomalies near ~10 Ma that may reflect prolonged exposure to enhanced
radiation during a cold cloud crossing.  A convergence of recent advances
across astronomy, space physics, and paleoclimate creates an unprecedented
opportunity to rigorously test this hypothesis. We now have high-precision
astrometry from the Gaia mission that allows one to reconstruct the Sun’s
trajectory through the Galaxy and to identify, with remarkable accuracy,
the interstellar structures it has encountered over the past ~10 Ma. Major
theoretical and modeling advances now enable quantitative predictions of
how the heliosphere evolved during these encounters. In this talk I will
discuss our recent work that show that during such periods, Earth was
exposed to increased radiation and large amounts of hydrogen. I will
discuss our preliminary results that show that the increase in hydrogen
augmented mesospheric water vapor, leading to increased formation of both
polar mesospheric clouds and polar stratospheric clouds. The amount of
radiation that Earth experiences from such events depends on the duration
of the crossing and the amount of compression of the heliosphere, with
implications for Earth’s climate. I will discuss our results as well that
indicate that high temporal 10Be signal in ocean records and ice cores can
distinguish between alternative scenarios such as supernova explosions and
cold cloud crossings.

The 2028 Summer Olympics will be held in Los Angeles from July 14–30, making Los Angeles only the third city(after London and Paris)to host the Summer Games three times. Los Angeles is an attractive Olympic venue not only because of its mild climate and global tourist appeal, but also because of its remarkable physical setting: a major coastal metropolis situated adjacent to actively deforming mountain ranges rising to elevations above 10,000 feet. This unique geological context provides an exceptional opportunity to connect a globally watched sporting event with public understanding of how Earth systems operate.
The geology of the Los Angeles region is far more dynamic and diverse than that of other Summer Olympic host cities. The convergence of intense public interest in the Olympics with an unusually compelling natural setting creates a rare opportunity for large-scale informal STEM education focused on Earth science and natural history. Leveraging this moment could engage audiences ranging from K–12 students to lifelong learners, both locally and worldwide. We refer to this proposed effort as the LA2028 GeOlympics.

This initiative aims to capitalize on global attention surrounding the 2028 Games by providing accessible, place-based explanations of the geological history of the Los Angeles region, particularly around Olympic venues, and by illustrating how tectonics, climate, and surface processes have shaped this iconic landscape. Achieving this goal will require coordinated collaboration among the region’s extensive educational and cultural infrastructure, including 14 college and university geology departments, 19 community colleges, approximately 2,000 K–12 schools, 136 museums, hundreds of environmental organizations, and a broad range of media outlets. This presentation outlines the vision for LA2028 GeOlympics, discusses organizational and funding needs, and explores pathways for collaboration with the LA28 Organizing Committee to transform the Olympics into a powerful platform for Earth science education.

The discovery of thousands of exoplanets revealed a huge variety in the sizes, masses, and orbital properties of planets outside of our solar system. I will discuss how the physics of gas accretion, dust-gas interaction, and star-disk-planet interaction can shape the observed diversity, providing explanations for some of the puzzling demographic patterns that have emerged in exoplanet science while placing our solar system in the larger Galactic context.

Planetary atmospheres are not static in time, and the many changes they experience can contribute to making a planet’s surface a more (or less) hospitable place. Interactions between a planet and its host star are especially important. They not only control the temperature of an atmosphere but can also drive atmospheric escape and atmospheric chemistry. In this presentation I describe ongoing efforts to understand what characteristics of a planet and its star, when combined together, allow the planet to retain an atmosphere that might be habitable at the planet’s surface. I’ll describe observations from planets in our solar system that inform this work, relevant modeling and observational efforts, and a team science effort dedicated to answering this guiding question.

Recent advances in Earth observation and computational techniques allow for the rigorous examination of climate and coastal sediment dynamics at scale. Leveraging these novel methods, we investigate how severe storms and oscillations in Earth’s climate affect Great Bahama Bank (GBB), the world’s largest modern isolated carbonate platform. High-fidelity hydrodynamic simulations suggest that a single hurricane has a negligible effect on the broad-scale distribution of sediments on the platform top, which is predominately sculpted by fair-weather conditions. Nevertheless, multi-decadal satellite monitoring intimates that catastrophic hurricanes, when occurring in quick succession, may be responsible for the remobilization of mud months to years after their passage. On longer time scales still, interannual and decadal variations in suspended sediment are linked to windy El-Niño events, tidal-forcing Lunar Nodal Cycles, and the weakening of the Atlantic Meridional Overturning Circulation. Spatial variations abound too. Surprisingly, sediment lofting along the leeward margin is linked to wind, while tide dictates resuspension on the windward margin. Finally, we present evidence others have found in the Holocene sedimentary record of the same climate signals we observe in the modern – linking platform top sediment dynamics to slope sedimentation. In doing so, we shed light on how modern analogues can be used to constrain past climate signals and predict sedimentological responses in the future.

The Juno spacecraft has been orbiting Jupiter since July 2016 and is completing its first extended mission.  My personal list of the five most important things we’ve learned from the Juno mission during its prime and extended missions goes something like this: 1. Jupiter has a fuzzy core. 2. Moist convection really is a dominant feature of Jovian atmospheric dynamics 3. Water seems to be supersolar in abundance, at least down hundreds of bars pressure.  4. Europa has a platypus-shaped crustal melt region. 5. There is an active lava flow at Zal Montes on Io.

The heat flow of a planetary body plays a major role in defining its evolution and current composition, driving processes from internal differentiation during its formation through geological activity at the current time. In this talk, I will describe how the ALMA (sub-)millimeter observatory and the James Webb Space Telescope are shedding light on the heat flow histories of satellites and small bodies. Thermal emission observations of asteroids provide information on the abundance and form of metals (ALMA) and minerals (JWST) on their surfaces. I will present ongoing asteroid programs aimed at providing a more complete compositional picture of asteroid surfaces, with implications for the early heating and differentiation of planetesimals. ALMA can also measure the isotopes of the volatile-forming elements, a key tool for studying the formation and evolution of objects in the Solar System. I will discuss sulfur and chlorine isotopes in the volcanic gasses of Jupiter’s moon Io in particular, and how they place constraints on the tidal heating and volcanism that Io experienced over the age of the Solar System.

Hot Jupiters — giant planets on short-period (< 10 days) orbits around their host stars -- represent the most extreme outcome of planet formation. Even though they were the first type of exoplanet around Sun-like stars to be discovered, their origins remain unclear. One challenge is our limited understanding of hot Jupiter statistics, as most of them were discovered by a heterogeneous collection of ground-based surveys with a variety of biases. NASA's Transiting Exoplanet Survey Satellite, a uniform all-sky transit search, presents the opportunity to revolutionize hot Jupiter demographics by unifying these previous planet searches. Over the past few years, I led the TESS Grand Unified Hot Jupiter Survey to confirm and characterize hundreds of planet candidates from TESS with facilities like Keck and Magellan. I will present the 4-sigma detection of a pile-up in the period distribution, the dependence of hot Jupiter occurrence on host star properties, and new evidence that they are found around a kinematically young galactic population. I will also discuss how our survey is enabling new lines of inquiry including the discovery of giant planets in the galactic thick disk, as well as detailed characterization of benchmark systems to test key physical processes like tidal inflation and orbital decay.

The field of exoplanets is evolving with astronomical speed, with over 6000 exoplanets discovered to date, including many planets that have no counterparts in the Solar System. More recently, the James Webb Space Telescope has revolutionized our understanding of exoplanet atmospheres by delivering unprecedented spectroscopic constraints on their atmospheric compositions.
In this talk, I will talk about my journey as a planetary scientist who started in the lab working with organic materials on Titan, and how I transitioned to working on some fun theoretical problems for exoplanet atmospheres. Specifically, I will discuss how we can use atmospheric composition to understand the nature and potential habitability of temperate sub-Neptunes, planets with sizes ranging between Earth and Neptune, which also represent the most common type of exoplanets discovered to date. I will also highlight my recent work addressing the emerging population of “missing methane” exoplanets.

The early evolution of the Earth-Moon system prescribes the tidal environment of the Hadean Earth and holds the key to the formation mechanism of the Moon. Estimating its early state by backtracking from the present, however, suffers from considerable uncertainties associated with ocean tides. Tidal evolution during the solidification of Earth’s magma ocean, on the other hand, has the potential to provide robust constraints on the Earth-Moon system before the appearance of a water ocean. To this end, it is of vital importance to understand how energy dissipates in a solidifying magma ocean and how tidal dissipation interacts with atmospheric evolution. These issues have turned out to be much more complicated than previously thought, and as it stands, many of the existing variations of the Moon-forming giant impact hypothesis appear to be unable to explain the present-day angular momentum of the Earth-Moon system, calling for further innovative ideas on the formation of the Moon.

Earthquakes occur naturally driven by tectonic processes, but they can also be induced by human activities. In particular, earthquakes induced by extraction or injection of fluids in the subsurface — during gas production, CO2 storage of geothermal operations for example — provide an opportunity to investigate earthquake physics and to test earthquake forecasting models. Our research shows that, in such examples, spatial and temporal variations in seismicity rate can be predicted reliably from stress changes inferred from reservoir operations and surface deformation measurements. These advances can improve methods for time-dependent seismic hazard assessment. However, forecasting individual events remains a major challenge.

Extreme weather and a warming climate can trigger cascading hazards that reshape landscapes and endanger infrastructure. This seminar explores how hydrology, climate, and geomorphology interact to cause or amplify land surface hazards, such as landslides, flooding, and permafrost degradation. By combining hydrologic modeling and remote sensing data, this work enhances understanding of the processes that link surface water, ground ice, and slope stability. The findings highlight the importance of interdisciplinary research in predicting and mitigating climate-related geohazards.

Groundwater renewability is a key factor in managing sustainable water resources in a changing climate. This seminar discusses new insights into groundwater age, flow pathways, and residence times across diverse aquifer systems. By integrating isotopic data and numerical modeling, the analysis reveals how recharge dynamics vary under different hydrogeologic settings. The results underscore the role of geologic structure and climate forcing in controlling groundwater sustainability and inform strategies for water management and policy.

The vast accumulation of carbon in Arctic soils—an estimated 1,700 Pg—has been referred to as a carbon bomb, a sleeping giant, and Pandora’s freezer. These terms all refer to the so-called ‘permafrost–carbon feedback,’ the cascading cycle in which warming temperatures destabilize permafrost soils, liberating large quantities of carbon to the atmosphere and driving further warming. But predicting whether Arctic landscapes will be a net source or sink of carbon requires tracking the transport and fate of the mobilized soil carbon and quantifying the strength of counteracting processes such as enhanced primary productivity of vegetation. I’ll show how the deposits of meandering rivers provide natural landscape-scale experiments that juxtapose frozen and thawed (permafrost and non-permafrost) terrain in the same environment, allowing us to track the changes to soil carbon and biomass reservoirs over timescales of years to millennia. These observations suggest that permafrost thaw may cause some Arctic landscapes to become a net carbon sink rather than a carbon source.

The deep sections of many modern subduction zones release strain through slow slip and tremor (SST), but the structures responsible, deformation mechanisms, and the role of syn-kinematic fluid flow remain hard to resolve from geodetic and seismologic data alone. Exhumed subduction zone rocks, such as those on Syros Island, Greece, provide key insights into the mechanical and hydrologic conditions within the SST source region. In this talk, I will present field-based and microstructural observations that reveal heterogeneity in viscosity, permeability, friction, and mineral fabrics, and discuss how these properties potentially influence deformation styles along subduction interfaces. These rock-based constraints help bridge the gap between geophysical observations and models, shedding light on the physical conditions that govern transitions between stable creep, slow slip, and seismic failure at depth.

Mars’ interaction with the solar wind exhibits a hybrid nature. The Martian magnetosphere, formed through interactions between the solar wind, ionosphere, and crustal magnetic fields, is complex and highly dynamic. While largely induced, it also contains localized regions where strong crustal fields dominate plasma dynamics. Global magnetohydrodynamic (MHD) modeling has become a critical tool for investigating this system and its role in atmospheric escape. Multi-species MHD studies first demonstrated the importance of ion-specific treatment at high spatial resolution, while later work revealed how rotating crustal fields modulate plasma boundaries and ionospheric structure. Applications to extreme events, such as the September 2017 ICME and the December 2022 disappearing solar wind event, highlighted the dynamic response of Mars’ plasma environment to solar wind variations, particularly density changes. This seminar will review advances in global MHD modeling of Mars and discuss their implications for understanding atmospheric escape and developing future space weather forecasting capabilities at the planet.

The Polarimeter to Unify the Corona and Heliosphere (PUNCH) is a constellation of four smallsats launching in Spring 2025 to image the solar corona and solar wind as a single unified system. The four satellites work together to form a single “virtual coronagraph” with a 90° field of view centered on the Sun. One satellite carries a coronagraph (the Narrow Field Imager) that captures the outer corona at apparent distances between 6 solar radii and 32 solar radii from the Sun. The other three carry heliospheric imagers with 42° wide fields of view, extending from 12 solar radii to 180 solar radii from the Sun. All instruments view visible light scattered by free electrons in the corona and solar wind and use linear polarization to generate 3D information about density structures in the plasma. In this talk, I will briefly describe some of the key background science and the mission itself, then discuss the enabling technologies of deep signal separation and polarimetric inversion to reveal 3D structure before presenting and discussing recent data from the constellation and how to obtain the data for your own use.

Space is never empty. Instead, it is filled with high-energy particles originating at the Sun and trapped by Earth’s magnetic field, forming dynamic radiation environments that pose significant risks to satellites, astronauts, and future exploration missions. In this talk, I will discuss the evolution of Earth’s radiation belts during geomagnetic storms, the processes that limit their intensity, and how similar processes may operate under artificially created conditions. I will present recent work on fast plasma processes that substantially alter radiation levels around Earth. My approach integrates data analysis, simulations, and the development of advanced particle detectors derived from technology originally designed at CERN, tailored specifically for space missions. Additionally, I will showcase results from a student-led balloon mission conducted during the most intense geomagnetic storm of the past two decades. 

Earth’s outer radiation belt is a doughnut-shaped region in space, containing stably trapped energetic electrons. Its outer boundary is closely related to the electron isotropy boundary (IB), which separates the outer radiation belt from the isotropic, precipitating electrons found further out, in the tail current sheet. Field-line curvature scattering (FLCS) is believed to play an important role in causing this isotropic electron precipitation and is effective when the electron gyroradius becomes comparable to the field line curvature radius in the equatorial current sheet region. However, the direct and quantitative impact of FLCS in controlling the outer belt electron lifetimes has never been directly assessed. In this talk, I will discuss the role of FLCS in controlling the outer belt electron lifetimes by combining observations and global radiation belt electron simulations. I will also reveal that this simple yet fundamental physical process which has been historically neglected in global radiation belt models, is sufficient to explain the outer electron belt configuration. Our findings transform our understanding of the dominant processes controlling radiation belt dynamics.

Jupiter’s moon Europa is thought to possess a subsurface ocean that could have the right conditions to harbor life. It will be visited by the Europa Clipper mission starting in 2030. To characterize this ocean and answer questions about habitability, the complex and highly variable plasma environment must be accounted for. In this talk, I will introduce a novel machine learning framework, including both forward and inverse modeling, to better understand the environment. Crucially, our model can reproduce the magnetic field, helping us define the depth, salinity, and conductivity of a potential subsurface ocean. These findings benefit both the upcoming missions to Europa and proposed missions to other planetary bodies such as those at Uranus or Neptune.

Magnetic reconnection occurs continuously along long X-lines at the Earth’s magnetopause. The maximum magnetic shear model provides accurate predictions for the locations of these long X-lines for a wide range of upstream solar wind conditions. One of the more perplexing observational results is that these X-lines appear to be stationary, even on the near-flank magnetopause in the presence of significant magnetosheath plasma bulk flow. An alternate possibility is that X-lines form in the location predicted by the maximum magnetic shear model but then immediately propagate with the magnetosheath plasma bulk flow away from this location. If the X-line reformation cadence is high enough and some other conditions are valid, then these multiple propagating X-lines could appear as a single quasi-stationary X-line at the location predicted by the maximum magnetic shear model. Magnetospheric multiscale observations are used to perform initial tests of this alternate possibility. Results from these initial tests show that there may be multiple X-lines near the predicted location of the X-line, and therefore this alternate possibility may have merit. This alternate possibility may have implications for the magnetospheric cusps. Magnetic reconnection at the magnetopause produces distinct energy-latitude ion dispersion features in the cusps. Multiple reconnection X-lines may produce overlapping dispersion features depending on how they are formed. Therefore, under the right solar wind conditions, there may be many instances of overlapping dispersion features. Observations from the Tandem Reconnection and Cusp Electrodynamics Reconnaissance Satellites (TRACERS) are used to investigate this possibility.

Magnetosphere and ionosphere coupling is largely driven by electromagnetic waves (e.g., Alfven waves) and particle precipitation in the polar cusp and auroral region. This coupling is inherently dynamic, nonlinear, and multiscale. Ionosphere magnetic perturbations (δB) span scales from >1,000 km across the auroral zone—associated with Region-1 and Region-2 field-aligned currents (FACs)—down to <1 km, approaching the electron inertial length and corresponding to fine-scale auroral arcs (~100 m). These smaller scale δB are often linked to inertial Alfven waves that carry parallel electric fields, accelerate electrons, and produce dynamic auroral structures. During geomagnetic storms and substorms, transient currents associated with these small-scale δB can exceed several hundred μA/m2, leading to ionosphere total electron content (TEC) perturbations and plasma irregularities that cause GPS scintillations and disrupt communication. Characterizing these small-scale δB and their space weather effects remains challenging due to Doppler shift from spacecraft motion (~7.8 km/s) and the scarcity of tandem spacecraft observations of electric and magnetic field measurements necessary to distinguish DC and wave components. NASA's TRACERS mission, launched on 24 July 2025, offers new opportunities to investigate these processes. Here we present initial results from TRACERS MAG observations of a coincident small-scale δB and GPS scintillation event.

The Low-Latitude Ionosphere/Thermosphere Enhancements in Density (LLITED) mission consisted of two 1.5U CubeSat to study nighttime ionosphere/thermosphere coupling. Each CubeSat hosts three science payloads: an ionization gauge (MIGSI) to observe neutral density, a planar ion probe (PIP) to observe plasma density, and a GPS radio occultation sensor for observing (CTECS-A) total electron content. The overall mission, from proposal to on-orbit operations and science investigations, has presented a number of challenges often requiring difficult decisions and compromise in order to maximize the science returns. The various orbit and technical difficulties necessitated a modification and reprioritization of LLITED’s science mission objectives. By modifying the mission science goals, prioritizing event-associated observations, and combining data from other missions and observational conjunctions, LLITED provided insightful observations of neutral and plasma density structures and coupling. This presentation will provide an overview of LLITED’s datasets, describe the various on-going studies, and highlight observations of neutral and plasma density structures at high and mid- latitudes, as well as observations of short time stability of small-scale density structures.

Alfvén waves, named after the Nobel laureate Hannes Alfvén, are a fundamental mode in magnetized plasmas. It has long been established that they play a key role in the energy circulation of the magnetosphere-ionosphere (M–I) coupling system. However, their dissipation on meso- and small-scales is much less well understood. Here, we examine how Alfvén waves drive several common meso-scale structures, including the auroral arcs, auroral beads, and the magnetospheric cusp. We find that Alfvén waves, although being the common energy source, are dissipated differently among these structures. In the auroral arcs, Alfvén waves power a quasi-static parallel electric field that accelerates ions away from and electrons toward the ionosphere. In the auroral beads, electrons are accelerated directly by the wave’s own parallel electric field. In the cusp, Alfvén waves significantly energize the outflowing ions, presumably through perpendicular heating. These distinct energy conversion processes we have unveiled are important in understanding the meso-scale M–I coupling on Earth and other planets. Our results also raise important questions for future studies: How are these Alfvén waves generated? What additional dissipation mechanisms may be operating? Why are Alfvén waves dissipated differently, and what are the controlling factors?

High-resolution spectroscopy is essential for resolving fine spectral features that reveal important physical processes in planetary, astrophysical, and heliophysical environments. However, traditional high-R instruments are large, complex, and incompatible with compact or distributed space platforms. We present a new generation of Spatial Heterodyne Spectroscopy (SHS) systems that overcome these limitations through a fully integrated, all-reflective, and monolithic design. Optimized for the FUV/EUV regime (10–200 nm), our SHS architecture delivers resolving powers of R ~20,000–100,000 in a compact form factor (<2U volume, <10 kg), making it ideal for CubeSats, SmallSats, and deep-space missions. We highlight critical system-level innovations, including thermal, optomechanical, and detector interfacing, as well as a validated performance model that includes sensor and electronics noise, optomechancial alignment tolerance, calibration and operation stability. These developments establish SHS as a scalable, high-fidelity spectroscopic solution for the next generation of space science missions.

Astrophotonics is the application of versatile photonic technologies to channel, manipulate, and disperse guided light from one or more telescopes to achieve scientific objectives in astronomy in an efficient and cost-effective way. The photonic platform of guided light in fibers and waveguides has opened the doors to next-generation instrumentation for both ground- and space-based telescopes. Utilizing the photonic advantage is a promising approach to massively miniaturize the next generation of spectrographs for ground- and space-based telescopes. I will discuss some of our recent results from our efforts to design and fabricate high-throughput on-chip astrophotonic spectrographs. These devices are ideally suited for enabling exciting science cases, such as measuring exoplanet masses and characterizing exoplanet atmospheres. I will also discuss specific approaches to make this technology science-ready and qualified for the next generation of space missions and potentially, planetary missions.

Surface observations of Saturn’s moon Titan revealed features characterized as dissected, elevated plateaus with high valley density known as labyrinth terrains. Of this terrain class, a subtype referred to as radial labyrinth is described as dome-shaped uplifts with radial channel patterns. Uplift of these radial labyrinths has been explained as cryomagmatic intrusions at the brittle-ductile transition zone. Here we propose an alternative hypothesis, that crustal heterogeneities in Titan’s upper clathrate crust introduce density differentials due to ethane-methane substitution, as ethane-rich liquids percolate into methane clathrate, inducing solid state flow and generating domal topography. This mechanism is analogous to salt tectonics on Earth and has similarly been evoked for dome formation on the dwarf planet Ceres. We show that the elevation and width of the observed radial labyrinths is consistent with domal uplift driven by a hydraulic head within the uppermost portion of Titan’s crust, given a plausible set of elastic parameters for clathrate hydrates. Additionally, the insulating effect of clathrate, combined with partial mixing with water-ice, allows for sufficiently low viscosity for geologic flow: uplift of the domes could have occurred early in Titan’s history, a billion years ago, or could have uplifted within the last 100 Myr during a recent phase of orbital excitation.

In this talk I will share our recently published results on the detection of potential biosignatures within the Neretva Vallis ancient riverbed on Mars, and then extend outward to our efforts to characterize and explore worlds of the outer solar system that harbor contemporary liquid water oceans beneath lithospheres of ice. At least six ice-covered moons of the outer solar system present compelling evidence for subsurface oceans, and thus provide highly compelling targets in our search for life beyond Earth. I will focus on Jupiter’s moon Europa, and detail experiments conducted in my lab that help us better understand Europa’s ocean chemistry and surface morphology. If time permits, I will also provide an overview of missions that will explore these worlds in the coming decades, and describe how exploration of Earth’s ocean and cryosphere is helping to guide our understanding of the potential habitability of these alien oceans.

Martian meteorites provide key information about the geological history of Mars. However, our collection is biased by geologically young samples that are not representative of Mars’ exposed surface, which is dominated by ancient rocks. This generates gaps in our knowledge of Mars’ early evolution. Recently, we discovered that a Martian meteorite, Teghaza 001, is a gabbroic diorite with a crystallization age > 4.1 Ga. In this presentation, I will describe this unique sample, how it compares to other Martian meteorites and igneous rocks studied by rovers, what results imply to our understanding of early Mars differentiation.