EPSS Colloquium - winter-2025
DART and Hera: first steps towards testing kinetic impactor mitigation of Potentially Hazardous Asteroids (PHAs)
Jan. 7, 2025
3:30 p.m. - 4:30 p.m.
Slichter Hall # 3853
Presented By:
- Bonnie Buratti - Jet Propulsion Laboratory
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The Double Asteroid Redirection Test (DART) was the first successful test of the kinetic impact strategy to deflect an asteroid. Physical characterization of the effects of the impact on the Didymos-Dimorphos binary system are an important next step. The European Space Agency’s Hera mission is currently on its way to study the physical and dynamical effects of the DART impact. This talk will describe how a combination of photometric modeling and ground-based observations can answer such questions as: What is the extent and nature of the impact site? How does the subsurface composition, texture, and albedo differ from that of the surface? Can the combined results from the two missions place limits on the effects of space weathering?
Stardust in Samples from Asteroid (101955) Bennu
Jan. 21, 2025
3:30 p.m. - 4:30 p.m.
3853 Slichter Hall
Presented By:
- Prof. Pierre Haenecour - University of Arizona
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Carbonaceous asteroids offer insight into the primordial materials that formed planets within the protoplanetary disk. They contain organic matter and tiny dust particles known as presolar grains, which originate from the envelopes of aging stars and the remnants of stellar explosions, including novae and supernovae before the birth of our Solar System. These stardust grains are crucial for understanding the building blocks of our Solar System. The recent sample return from asteroid (101955) Bennu by NASA’s OSIRIS-REx mission provides a new opportunity to examine the distribution and abundance of presolar grains in carbonaceous asteroids. In my talk, I will present the preliminary laboratory analysis of the Bennu samples.
Space Weather Effects from Magnetic Induction
Jan. 28, 2025
3:30 p.m. - 4:30 p.m.
Slichter Hall # 3853
Presented By:
- Prof. Martin Connors - Athabasca University
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Space weather includes many effects, but those on technological systems at ground level are most pronouncedly associated with magnetic induction. Electric fields induced by changing magnetic fields are often in undesired places and at problematic frequencies, thus usually having a negative effect on large ground infrastructure such as electric distribution networks. Their effects build up in large systems but are small locally, making them hard to measure. Historically, the field of magnetotellurics (MT) has measured these fields along with magnetic fields, allowing Earth structure to be inferred. In MT, satisfactory results are often obtained with simplifications such as vertically incident waves and associated neglect of any vertical magnetic component. For space weather purposes it is possible that “source effects” violating these assumptions are important. Recent work on this will be described, along with examination of the May 2024 “Gannon” storm, including with electric field and power network measurements.
Paleomagnetic Insights into Impact Processes at Chicxulub Crater
Feb. 4, 2025
3:30 p.m. - 4:30 p.m.
3853 Slichter Hall
Presented By:
- Prof. Sonia Tikoo-Schantz - Stanford University
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Impact cratering is arguably the most ubiquitous modifier of planetary surfaces across the solar system. Impacts expose target rocks to powerful shock waves and heat that can substantially modify their physical properties. Subsequently, hot fluids moving through crater rocks can generate long-lived hydrothermal systems that can serve as habitats for thermophilic microorganisms. Shock, heat, and alteration can produce different forms of remanent magnetization that are preserved within craters, and thus paleomagnetism may be used to elucidate a variety of impact processes. Here we discuss how paleomagnetic records and bulk rock magnetic properties from the 66 million-year-old, 200-km diameter, Chicxulub impact crater shed light into how the crater formed, the origin of magnetic anomalies, the nature and duration of post-impact hydrothermal activity, and implications for the habitability of post-impact environments.
Tracing Solar System Formation Through Clast Diversity and Origins
Feb. 11, 2025
3:30 p.m. - 4:30 p.m.
3853 Slichter Hall
Presented By:
- Dr. Imene Kerraouch - NASA Johnson Space Center
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My research aims to deepen our understanding of astromaterial diversity and the environmental conditions that led to the emergence of diverse celestial bodies by testing multiple physical models. The primary objective of my research is to examine the mineralogical and cosmochemical diversity within primitive meteorites and asteroid samples, such as those returned by the Hayabusa2 mission from asteroid Ryugu. A key focus is the investigation of foreign clasts in various meteorite groups, including in carbonaceous chondrites (CC) and non-carbonaceous (NC) types. The distinct physicochemical properties of these clasts offered insights into current and past asteroid populations, as some exhibit xenolithic origins that do not match with known meteorite groups. The goal of my research is to determine the formation timing and regions of these unique materials within the early solar system, as well as the secondary processes—such as aqueous alteration, thermal metamorphism, heating, brecciation, and mixing—that influenced their evolution. I employed a multidisciplinary approach, such as Secondary Ion Mass Spectrometry (SIMS), electron microprobe analysis, Transmission Electron Microscopy (TEM), and other advanced methods, to reconstruct the timeline and environmental conditions that shaped these parent bodies. The outcomes of this research expand our knowledge of astromaterial diversity and offer new perspectives on the dynamic processes that governed the early solar system's evolution.
Songs of Ice and Fire: Fiber Seismic Sensing over Antarctica and Iceland
Feb. 18, 2025
3:30 p.m. - 4:30 p.m.
3853 Slichter Hall
Presented By:
- Prof. Zhongwen Zhan - Caltech
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Glaciers and volcanoes are some of the most spectacular places on Earth and are very important to our environment. While satellites have greatly improved our coverage, continuous in-situ geophysical measurements remain difficult due to harsh conditions and remote locations. Yet, these measurements are critical for understanding their internal structures and dynamics. In this talk, I will share how we used continuous fiber-optic seismic sensing in Antarctica and Iceland, turning kilometers of fiber-optic cables into dense seismic arrays. Our results reveal new insights into ice flow, subglacial processes, and volcanic activity, showing how fiber-optic technology can capture subtle changes in these environments. I will also discuss the scientific findings and lessons for future expansions.
Ecosystem Impacts of Antarctic Methane: Unraveling Southern Ocean Ecosystem Function from Emergent (Very) Cold Seeps
Feb. 25, 2025
3:30 p.m. - 4:30 p.m.
3853 Slichter Hall
Presented By:
- Prof. Andrew Thurber - UCSB
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Deep-sea methane seeps are areas where critical and unique ecosystem functions impact the biodiversity of the marine realm. These greenhouse-gas fueled habitats are both climate sensitive as well as potentially deterministic in the fate of our global climate. The role and function of methane in Antarctica remains a significant knowledge gap in our understanding of seepage to regional and global processes. Through studying the only known high Antarctic methane seep through a combination of observational and empirical approaches, we have unraveled a perplexing role of methane that permeates throughout the benthic Antarctic Ecosystem. From unique microbial methane sinks, to a ubiquity of methane cycling that is integrated into the animal food web, and even a potentially causative link to an outbreak of Sea Star Wasting Syndrome, our research on the most southerly (very) cold seep is providing insight into the current and future function of polar ecosystems that can directly impact atmospheric futures.
Reconstructing life: molecular paleobiology and the search for origins
March 4, 2025
3:30 p.m. - 4:30 p.m.
3853 Slichter Hall
Presented By:
- Prof. Betül Kaçar - Univerity of Wisconsin-Madison
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Life existed on our planet for nearly 4 billion years. The majority of our planet’s history is inhabited by microbial life. Since the dawn of life, ancient microbes left their mark at the planetary scale. It was ancient microbes that produced greenhouse gases, and it was microbe hosted cellular nanomachines that responded to planet level geochemical changes. What are the planet-scale impacts mediated by microbes and how did they emerge? What are the significant historical innovations of life that shaped the life we observe today? In this talk, I will introduce the concept of molecular paleobiology, which focuses on the dynamics between life and environment over planet Earth’s history, with special emphasis on Precambrian biota and deep time functional evolution. I will particularly discuss our studies connecting the molecular underpinnings of life with corresponding planetary scale changes in geochemistry, focusing on the emergence and evolution of essential microbial metabolisms and microbes impacting and impacted by significant changes in the environment, including the Great Oxidation Event, as well as the presence or absence of dissolved metals in the oceans. Finally, I will discuss how understanding the origins and early evolution of life on Earth may allow for the recognition of life elsewhere in the universe by exploring, assessing, and discussing various signs of life, and the processes that expands life from molecular to planetary scale.