Timothy Lyons

Using Earth’s history to inform the search for life on exoplanets

Anonymous — Tue, 08 Dec 2020 16:26:50 +0000

Using Earth’s history to inform the search for life on exoplanets Anonymous (not verified) Tue, 12/08/2020 - 08:26 More News Jules Bernstein | UCR News December 08, 2020

UC Riverside is leading one of the NASA Astrobiology Program’s eight new research teams tackling questions about the evolution and origins of life on Earth and the possibility of life beyond our solar system.

The teams comprise the inaugural class of NASA’s Interdisciplinary Consortia for Astrobiology Research program. The UCR-led team is motivated by the fundamental question of how to detect planets that could host life and remain habitable despite tremendous change over time, which requires hunting for biological gases in the atmospheres of planets light years beyond our solar system.

This image shows an Earth-like "exomoon" orbiting a gas giant planet in a star's habitable zone. (NASA/JPL-Caltech)

“To achieve this goal, our research focuses on the many diverse chapters of Earth’s history — or alternative Earths — that span billions of years and offer critical templates for examining exoplanets far beyond our solar system,” said UCR biogeochemist Timothy Lyons, the project leader.

Because of their immense distance from us, humans will likely never visit those planets, at least not soon, Lyons said. However, in the near future, scientists will be able to analyze the compositions of these planets’ atmospheres, looking for gases like oxygen and methane that could come from life.

Earth has undergone dramatic changes over the last 4.5 billion years, with major transitions occurring in plate tectonics, climate, ocean chemistry, the structure of our ecosystems, and composition of our atmosphere.

“These changes represent an opportunity,” Lyons said. “The different periods of Earth’s evolutionary history provide glimpses of many, largely alien worlds, some of which may be analogs for habitable planetary states that are very different from conditions on modern Earth.”

Exciting new research frontiers for Lyons’ team include studies of Earth’s first 500 million years, as well as predictions about our planet and its life billions of years in the future.

Studying biosignature gases in Earth’s past will allow the team to design telescopes and refine interpretative models for potential traces of life in distant exoplanet atmospheres, noted Georgia Tech biogeochemist Christopher Reinhard.

Once the researchers understand how Earth and its star — the sun — changed together to maintain liquid oceans teeming with life over billions of years, the team can predict how other planetary systems might also have developed and maintained life and better understand how to search for it.

“Such a ‘mission to early Earth’ must include broad interdisciplinary within the team, impactful synergy within and across the Research Coordination Networks, or RCNs, of the NASA Astrobiology Program, and a commitment to deliverables that will help steer NASA science for decades to come,” said UCR astrobiologist Edward Schwieterman.

Success in this mission will require biological, chemical, geological, oceanographic, and astronomical expertise. Yale University biogeochemist Noah Planavsky said, “our team brings all that to the table.” Accordingly, the diverse expertise within the team includes astronomers, planetary scientists, geologists, geophysicists, oceanographers, biogeochemists, and geobiologists.

The team will collect ancient rock samples and modern sediments from around the world spanning billions of years and use the data they generate to drive wide-ranging computational models for Earth’s ancient and future oceans and atmospheres.

“The models will allow the team to evaluate whether different periods in Earth’s history were characterized by gases that would have been detectable from a distant vantage as products of life, much the way oxygen fingerprints life on our planet today,” said Purdue University Earth and exoplanetary scientist Stephanie Olson.

This work requires a multipronged view of the Earth as a complex system that has varied dramatically over time. Yet despite all the change, Earth has remained persistently habitable, with liquid water oceans teeming with life.

How Earth became and remained habitable and whether its life would have been detectable to a distant observer are the questions that will ultimately define and refine the search for life on exoplanets.

“In short,” said Lyons, “the exciting goal of our team is to provide a new and more holistic view of Earth’s evolutionary history in order to help guide NASA’s mission-specific search for life on distant worlds.”

The RCNs are the new face of astrobiology at NASA, following 20 years of exciting research under the umbrella of the NASA Astrobiology Institute, which supported the UCR-led team previously.

The $4.6 million new award from NASA will span five years and includes team members from Georgia Tech, Yale University, Purdue University, UCLA, NASA Ames Research Center and collaborators from around the world.

Tim Lyons and Edward Schwieterman contributed significantly to this story.

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UCR team among scientists developing guidebook for finding life beyond earth

Anonymous — Fri, 04 Sep 2020 00:41:56 +0000

UCR team among scientists developing guidebook for finding life beyond earth Anonymous (not verified) Thu, 09/03/2020 - 17:41 More News Sarah Nightingale | UCR News June 25, 2018

If you’re looking for a manual on the hunt for alien life, you’re in luck.

Some of the leading experts in the field, including a UC Riverside team of researchers, have written a major series of review papers on the past, present, and future of the search for life on other planets. Published in Astrobiology, the papers represent two years of work by the Nexus for Exoplanet Systems Science(NExSS), a NASA-coordinated research network dedicated to the study of planetary habitability, and by NASA’s Astrobiology Institute.

Scientists have identified more than 3,500 planets around other stars (called exoplanets) and many more will be discovered in the coming decades. Some of these are rocky, Earth-sized planets that are in the habitable zones of their stars, meaning it’s neither too hot nor too cold for liquid water — and possibly life — to exist.

The five papers will serve as a reference for scientists searching for signs of life, called biosignatures, in the data they collect from future telescope observations.

“In less than 30 years, we’ve gone from not knowing whether planets existed outside our solar system to being able to pinpoint potentially habitable planets and collect data that will enable us to look for the signatures of life,” said Edward Schwieterman, a postdoctoral researcher in UCR’s Department of Earth Sciences and lead author on the first paper in the series. “These advances offer unprecedented opportunities to answer the age-old question, ‘are we alone?’, but at the same time demand that we move forward with great care by developing robust models that allow us to seek and identify life with a high degree of certainty.”

Schwieterman’s paper reviews three types of biosignatures that astrobiologists have previously proposed as markers for life on other planets, all of which must be remotely detected since exoplanets orbit distant stars that we cannot reach in person. The markers include:

Fingerprints of life. (NASA/Aaron Gronstal)

Gaseous biosignatures — byproducts of life that can be detected in the atmosphere, such as oxygen produced by photosynthesis, as on Earth.
Surface biosignatures — life-induced changes in the absorption and reflection of light on the surface of a planet, such as the red-edge caused when plants absorb red light during photosynthesis but reflect infrared light that is not used.
Temporal biosignatures — time-dependent fluctuations in gaseous or surface biosignatures, such as biologically modulated changes in the Earth’s atmosphere that occur during different seasons.

Schwieterman is part of UCR’s NASA-funded Alternative Earths Astrobiology Center, an interdisciplinary group that is developing a “search engine” for life on other worlds by delving into our own planet’s dynamic, 4.5-billion-year history. Though dramatically different in terms of atmospheric composition and climate, the different chapters of Earth’s history have one thing in common: oceans teeming with a remarkable diversity of simple and complex life.

“We are using Earth to guide our search for life on other planets because it is the only known example we have,” said Timothy Lyons, a distinguished professor of biogeochemistry and director of the Alternative Earths Astrobiology Center. “But Earth actually offers us a great diversity of possibilities. Rather than being constrained to a study of present-day life, we use geological and geochemical analyses to examine the billions of years that life survived, evolved, and thrived on Earth under conditions that are very different than today’s, hence the concept of ‘alternative Earths.’”

UCR's Edward Schwieterman.

Edward Schwieterman, a postdoctoral researcher in UCR’s Department of Earth Sciences.

Schwieterman’s review outlines the complexities of searching for life on planets that are too far away to visit, including phenomena called false positives and false negatives. “The search for life using biosignatures is not as simple as looking for a single molecule or compound. Atmospheric oxygen, for example, could be a sign of life, but there are many nonbiological ways that oxygen gas could be produced on an exoplanet. Conversely, it is possible that life could exist in the absence of oxygen gas, similar to early life on Earth or portions of the oceans today,” Schwieterman said. “This is one reason temporal biosignatures, which are based on dynamic phenomena such as atmospheric seasonality, might be more robust biosignatures in some circumstances.”

More research on the ways nature can fool scientists into thinking a lifeless planet is alive or vice versa is described in the second paper in the series. The third and fourth papers propose novel investigations that would expand our conception of biosignatures to myriad habitable planets that are radically different from past or present Earth. The final article discusses how the search for life through biosignatures is incorporated into telescope and mission design.

In addition to Schwieterman and Lyons, Stephanie Olson, a graduate student in Earth Sciences, contributed to this research. The team, together with Christopher Reinhard, an assistant professor at Georgia Institute of Technology and a member of UCR-led Alternative Earths Astrobiology team, contributed to several other papers in the series.

“Together, these papers highlight UCR’s contributions to the understanding of exoplanet biosignatures and the implications for instrument design going forward,” Schwieterman said.

“These articles will provide an entry point for people from disparate fields interested in how they too might contribute to the search for life outside our solar system.”

UCR’s Alternative Earths team is funded by the NASA Astrobiology Institute. Read a NASA news releaseabout this research.

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Search for life beyond the solar system topic of faculty research lecture

Anonymous — Fri, 04 Sep 2020 00:13:37 +0000

Search for life beyond the solar system topic of faculty research lecture Anonymous (not verified) Thu, 09/03/2020 - 17:13 More News Sarah Nightingale | UCR News May 16, 2018

Timothy Lyons, a distinguished professor of biogeochemistry in the Department of Earth Sciences and director of the Alternative Earths Astrobiology Center, will deliver the 66^th annual Faculty Research Lecture at UC Riverside. The Faculty Research Lecturer Award is the highest honor bestowed by the Academic Senate.

Timothy Lyons

The lecture, “Are We Alone? A Geologist’s Journey from Deep Time to Deep Space,” will take place from 3:30-5 p.m. on Friday, June 8, in the Genomics Auditorium, Room 1102A. It is presented by the UC Riverside Academic Senate.

The search for alien life is defining a new era of space exploration — from Mars and icy moons in our solar system to Earth-like planets orbiting distant stars. Lyons and his colleagues are cultivating a “search engine” for life on these other worlds by delving into our own planet’s dynamic, 4.5-billion-year history. Through Earth’s history, these many “alternative Earths” shared one thing in common: oceans teeming with a remarkable diversity of simple and complex life.

Lyons’ group has developed tools for reconstructing ephemeral landscapes of lost worlds using chemical fingerprints locked in ancient rocks. These stony archives are rich in direct and inferred traces of ancient life — known as biosignatures — that are guiding NASA’s search for life beyond our planet and solar system.

Lyons leads the Alternative Earths team of the NASA Astrobiology Institute and the Astrobiology Center at UC Riverside. He is an honorary professor at the University of St. Andrews and a fellow of the Geological Society of America, the American Association for the Advancement of Science, the Geochemical Society, and the European Association of Geochemistry. He has held multiple visiting professorships at universities around the world. His professional service includes a dozen editorial positions and numerous panels and advisory boards, including current membership on NASA’s Planetary Science Advisory Committee.

Lyons holds a bachelor’s degree in geological engineering from the Colorado School of Mines, a master’s in geosciences from the University of Arizona, and master’s and doctoral degrees in geochemistry from Yale University, followed by a postdoctoral fellowship at the University of Michigan. His primary research interests include astrobiology, geobiology, biogeochemical cycles through time, ancient climate, Earth history, and the search for life beyond our solar system.

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UCR scientists rank among world’s most influential scholars

Anonymous — Fri, 04 Sep 2020 00:02:10 +0000

UCR scientists rank among world’s most influential scholars Anonymous (not verified) Thu, 09/03/2020 - 17:02 More News Jules Bernstein | UCR News November 20, 2019

The world’s most influential scientific researchers in 2019 include 10 current UCR scholars.

In its annual list, Clarivate Analytics names the most highly cited researchers — those whose work was most often referenced by other scientific research papers for the preceding decade in 21 fields across the sciences and social sciences. The 2019 list is based on citations between 2008-18.

The researchers rank in the top 1% in their fields in producing widely cited studies, indicating their work is marked by “exceptional influence,” according to Clarivate. Current UCR faculty members and researchers named to the list and their primary UCR research fields are:

•   Julia Bailey-Serres, plant and animal science
•   Alexander Balandin, electrical engineering and materials science
•   Pingyun Feng, chemistry
•    Qi Chen, biomedical sciences
•   Hailing Jin, microbiology and plant pathology
•   Sang-Youl Park, plant and animal science
•    Sean Cutler, plant and animal science
•   Timothy Lyons, geosciences
•   Wei Ren, engineering
•   Yadong Yin, chemistry

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New study dramatically narrows the search for advanced life in the universe

Anonymous — Thu, 03 Sep 2020 23:12:12 +0000

New study dramatically narrows the search for advanced life in the universe Anonymous (not verified) Thu, 09/03/2020 - 16:12 More News Jules Bernstein | UCR News June 10, 2019

RIVERSIDE, CA – Scientists may need to rethink their estimates for how many planets outside our solar system could host a rich diversity of life.

In a new study, a UC Riverside–led team discovered that a buildup of toxic gases in the atmospheres of most planets makes them unfit for complex life as we know it.

Traditionally, much of the search for extraterrestrial life has focused on what scientists call the “habitable zone,” defined as the range of distances from a star warm enough that liquid water could exist on a planet’s surface. That description works for basic, single-celled microbes — but not for complex creatures like animals, which include everything from simple sponges to humans.

The team’s work, published today in The Astrophysical Journal, shows that accounting for predicted levels of certain toxic gases narrows the safe zone for complex life by at least half — and in some instances eliminates it altogether.

“This is the first time the physiological limits of life on Earth have been considered to predict the distribution of complex life elsewhere in the universe,” said Timothy Lyons, one of the study’s co-authors, a distinguished professor of biogeochemistry in UCR’s Department of Earth and Planetary Sciences, and director of the Alternative Earths Astrobiology Center, which sponsored the project.

“Imagine a ‘habitable zone for complex life’ defined as a safe zone where it would be plausible to support rich ecosystems like we find on Earth today,” Lyons explained. “Our results indicate that complex ecosystems like ours cannot exist in most regions of the habitable zone as traditionally defined.”

Using computer models to study atmospheric climate and photochemistry on a variety of planets, the team first considered carbon dioxide. Any scuba diver knows that too much of this gas in the body can be deadly. But planets too far from their host star require carbon dioxide — a potent greenhouse gas — to maintain temperatures above freezing. Earth included.

“To sustain liquid water at the outer edge of the conventional habitable zone, a planet would need tens of thousands of times more carbon dioxide than Earth has today,” said Edward Schwieterman, the study’s lead author and a NASA Postdoctoral Program fellow working with Lyons. “That’s far beyond the levels known to be toxic to human and animal life on Earth.”

The new study concludes that carbon dioxide toxicity alone restricts simple animal life to no more than half of the traditional habitable zone. For humans and other higher order animals, which are more sensitive, the safe zone shrinks to less than one third of that area.

What is more, no safe zone at all exists for certain stars, including two of the sun’s nearest neighbors, Proxima Centauri and TRAPPIST-1. The type and intensity of ultraviolet radiation that these cooler, dimmer stars emit can lead to high concentrations of carbon monoxide, another deadly gas. Carbon monoxide binds to hemoglobin in animal blood — the compound that transports oxygen through the body. Even small amounts of it can cause the death of body cells due to lack of oxygen.

Carbon monoxide cannot accumulate on Earth because our hotter, brighter sun drives chemical reactions in the atmosphere that destroy it quickly. Although the team concluded recently that microbial biospheres may be able to thrive on a planet with abundant carbon monoxide, Schwieterman emphasized that “these would certainly not be good places for human or animal life as we know it on Earth.”

Scientists have confirmed nearly 4,000 planets orbiting stars other than the sun, but none of them will be possible to visit in person. They are simply too far away. Closest is Proxima Centauri b, which would take 54,400 years for current spacecraft to reach. Using telescopes to detect abundances of certain gases in their atmospheres is one of the only ways to study these so-called exoplanets.

“Our discoveries provide one way to decide which of these myriad planets we should observe in more detail,” said Christopher Reinhard, a former UCR graduate student now an assistant professor at the Georgia Institute of Technology, co-author of this study, and co-leader of the Alternative Earths team. “We could identify otherwise habitable planets with carbon dioxide or carbon monoxide levels that are likely too high to support complex life.”

Findings from the team’s previous work is already informing next-generation space missions such as NASA’s proposed Habitable Exoplanet Observatory. For example, because oxygen is essential to complex life on Earth and can be detected remotely, the team has been studying how common it may be in different planets’ atmospheres.

Other than Earth, no planet in our solar system hosts life that can be characterized from a distance. If life exists elsewhere in the solar system, Schwieterman explained, it is deep below a rocky or icy surface. So, exoplanets may be our best hope for finding habitable worlds more like our own.

“I think showing how rare and special our planet is only enhances the case for protecting it,” Schwieterman said. “As far as we know, Earth is the only planet in the universe that can sustain human life.”

In addition to Schwieterman, Lyons, and Reinhard, the paper’s authors are Stephanie Olson from the University of Chicago and Chester E. Harman from Columbia University. This project was funded by the NASA Astrobiology Institute.

Three planets orbiting TRAPPIST-1 fall within that star’s habitable zone. (Image courtesy of R. Hurt/ NASA/JPL-Caltech/)

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Experts on the Salton Sea

Anonymous — Thu, 03 Sep 2020 23:06:52 +0000

Experts on the Salton Sea Anonymous (not verified) Thu, 09/03/2020 - 16:06 More News UCR News October 10, 2019

For fast access to experts, TEXT or call the 24-hour-experts hotline at 951-312-3049, or email news@ucr.edu

Salton Sea

Emma Aronson: Associate professor of microbiology and plant pathology. Microbiome of the Salton Sea; microbial ecology of dust; wind- transported microorganisms; environmental microbiology; soil microbial ecology. emma.aronson@ucr.edu

Roya Bahreini: Associate professor of atmospheric science. Aerosol sources and composition; atmospheric processes that generate aerosols; aerosol effects on climate; air quality. roya.bahreini@ucr.edu

Ann Cheney: Assistant professor in the Center for Healthy Communities. Respiratory problems among migrant farmworkers living around the sea; structural inequalities in health; substance use; mental health issues; Latino immigrant health. ann.cheney@medsch.ucr.edu

Marilyn Fogel: Wilbur W. Mayhew endowed professor of geoecology, director of UCR’s Environmental Dynamics and GeoEcology Institute, and member of the National Academy of Sciences. Fogel is studying how the Salton Sea has changed chemically over time, and how these changes have affected its ecosystem. Her work establishes predictive models that will help policymakers evaluate which of the various wetland restoration plans under consideration will protect not only the endangered bird species, but also the health of the people in the area. Marilyn.fogel@ucr.edu

Darrel Jenerette: Director of the Center for Conservation Biology and professor of botany and plant sciences. Desert ecosystems; ecological landscapes; various land uses; sustainability; air pollution and soil interaction. darrel.jenerette@ucr.edu

David Lo: Director of the BREATHE Center and distinguished professor of biomedical sciences. Asthma; inflammation; immune system; health care disparities. david.lo@medsch.ucr.edu

Todd Luce: Doctoral candidate in the Department of History. An environmental historian, Luce has shaped his doctoral thesis into what he calls an “eco-biography” of the Salton Sea. His research pushes back against the narrative that the sea’s creation was accidental, and his areas of interest include water conflict, land development and policy, disaster and society, and California history. In addition to his work at the Salton Sea, Luce has conducted National Park Service-funded historical research at Joshua Tree National Park. tluce002@ucr.edu

Tim Lyons: Distinguished professor of biogeochemistry. Lyons is an expert in sedimentary geochemistry, biogeochemical cycles and astrobiology. His work explores the evolving oceans and atmosphere, and their roles in the origin and evolution of life. Lyons has examined the Salton Sea’s major chemical ingredients – including carbon, nitrogen, hydrogen, sulfur and metals. Most of these elements exist in two or more forms, called isotopes. By measuring the ratios of these isotopes in microbes and animal bones, Lyons can determine how the lake has changed over time, and how these changes have affected its ecosystem. As director of UCR’s NASA-funded Alternative Earths Astrobiology Center, he is known for developing tools to reconstruct ephemeral landscapes of lost worlds using chemical fingerprints locked in ancient rocks. Timothy.lyons@ucr.edu|

Tara Nordgren: Assistant professor of biomedical sciences. Lung health; lung inflammation; inflammatory disease. tara.nordgren@medsch.ucr.edu

Will Porter: Assistant professor of atmospheric dynamics and modeling. Air-quality modeling; atmospheric science; wind-speed fluctuations and dust migration; health and environmental impacts of land-use changes. william.porter@ucr.edu

Kurt Schwabe: Professor of environmental economics and policy. Schwabe’s research focuses on economic issues associated with water use and reuse, agricultural production, urban water conservation, ecosystem services, and environmental regulation. He has studied the Salton Sea and associated policies since the early 2000s, and he advocates for short-term solutions such as field fallowing to redirect conserved water from farmers to the sea. He has co-organized two Salton Sea summits, bringing together representatives from local and regional water authorities, state and federal agencies, county and state governments, universities, and community advocacy organizations. kurt.schwabe@ucr.edu

Barry Wallerstein: Senior policy fellow in the School of Public Policy. Wallerstein served for nearly two decades as executive officer of the South Coast Air Quality Management District, the regional agency charged with achieving clean air in Southern California. At his urging, the agency installed monitors at the Salton Sea to assess airborne levels of hydrogen sulfide, a potentially toxic gas created by decaying organic material in the lakebed and water that becomes agitated during storms, and help determine when and whether evacuation might be necessary for residents. Wallerstein has also testified about the sea before California’s Little Hoover Commission, an independent state oversight agency, calling it an “environmental travesty.” barry.wallerstein@ucr.edu

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New NASA research consortium to tackle life's origins

Anonymous — Thu, 03 Sep 2020 22:59:27 +0000

New NASA research consortium to tackle life's origins Anonymous (not verified) Thu, 09/03/2020 - 15:59 More News PCE3 Consortium | UCR News February 14, 2019

Did life on Earth originate in Darwin's warm little pond, on a sunbaked shore, or where hot waters vent into the deep ocean? And could a similar emergence have played out on other bodies in our solar system or planets far beyond? These questions lie at the center of research in NASA's new Prebiotic Chemistry and Early Earth Environments, or PCE3, Consortium.

One of five cross-divisional research coordination networks with the NASA Astrobiology Program, PCE3 aims to identify planetary conditions that might give rise to life's chemistry. One goal of PCE3 is to guide future NASA missions targeting discovery of habitable worlds.

"This new consortium has the potential to transform how we research the origins of life. The consortium will advance understanding of how life begins, by cross-fertilizing the community, enabling new collaborations, and fundamentally changing the dialogue across diverse intellectual expertise," said Lori Glaze, acting director of the Planetary Science Division at NASA Headquarters.

One of the objectives of this community is to better understand early Earth environments and make this knowledge accessible to a broad scientifically diverse community through a virtual interactive portal.

"With this approach, we will incorporate realistic planetary conditions into prebiotic chemistry experiments, leading to models for the emergence of life that are consistent with what we know of our planet's early history," said Karyn Rogers of Rensselaer Polytechnic Institute, one of four PCE3 co-leaders and a recent NASA Astrobiology Program award recipient.

A dedicated steering committee to coordinate the consortium's cross-disciplinary interactions will be led by Rogers, Ram Krishnamurthy of the Scripps Research Institute, Loren Williams of the Georgia Institute of Technology, and Timothy Lyons of the University of California, Riverside.

"Among the group's initial tasks will be to investigate how small molecules are synthesized on, or delivered to, the early Earth and how these might survive and subsequently form more complex compounds in early Earth environments that could have harbored life's emergence," Krishnamurthy said.

These studies will be undertaken in parallel with more detailed investigations of the earliest conditions on Earth, incorporating recent evidence for the early formation and persistence of liquid oceans.

"Deconstructing life's origins requires a rich understanding of the environmental and chemical conditions during Earth's early history and on how life developed and progressed in a world very different than today's," Williams said.

"I am particularly excited to frame the beginnings of life within the context of our planet's early, dynamic habitability and to use those lessons to imagine how planets around distant stars similarly could have favored the origins and evolution of life," Lyons said.

Astrobiology is the multidisciplinary study of the origin, evolution, distribution, and future of life in the universe. This discipline is increasingly playing a central role in NASA's science mission to search for life beyond Earth. To better serve this role, the NASA Astrobiology Program has created a new programmatic infrastructure of five Research Coordination Networks (RCNs). The prototype RCN, the Nexus for Exoplanet System Science (NExSS), was organized in 2015, and the Network for Life Detection (NfoLD) was announced in late 2018. The PCE3 Consortium will be followed by two additional RCNs planned for 2019. For more information about this initiative, see https://astrobiology.nasa.gov/news/nasas-astrobiology-program-evolving-to-meet-the-future/ and https://astrobiology.nasa.gov/news/astrobiology-program-faqs/

For additional information, contact:
•   Karyn Rogers leads the interdisciplinary Rensselaer Astrobiology Research and Education Center, which explores the dynamics of early Earth environments and their potential to foster chemistries that might lead to life (rogerk5@rpi.edu).
•   Loren Williams leads the Center for the Origin of Life, an interdisciplinary team that is developing new conceptual and experimental tools to understand the origin and early evolution of life on Earth (ldw@gatech.edu).
•   Ram Krishnamurthy is a member of the Simons Foundation Collaboration on the Origins of Life and the Center for Chemical Evolution and leads a research group that uses prebiotic and synthetic organic chemistry to inform the advent of protometabolic pathways and informational polymers (rkrishna@scripps.edu).
•   Tim Lyons leads the Alternative Earths Team of the NASA Astrobiology Institute. He and his colleagues use Earth's long history of biologic and planetary interactions and evolution to build predictive models of other habitable worlds--particularly planets outside our solar system (timothy.lyons@ucr.edu).
•   Lindsay Hays is the NASA Astrobiology Program deputy program scientist (lindsay.hays@nasa.gov).

Media contacts:

Holly Ober, UC Riverside
Mary Martialay, RPI
Maureen Rouhi, Georgia Tech
Chris Emery, Scripps

This press release was issued by the Prebiotic Chemistry and Early Earth Environments (PCE3) Consortium. Timothy Lyons, a distinguished professor of biogeochemistry at the University of California, Riverside, is one of four co-leads.

(header photo credit: RPI)

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Atmospheric seasons could signal alien life

Anonymous — Thu, 03 Sep 2020 22:43:50 +0000

Atmospheric seasons could signal alien life Anonymous (not verified) Thu, 09/03/2020 - 15:43 More News Sarah Nightingale | UCR News May 09, 2018

Dozens of potentially habitable planets have been discovered outside our solar system, and many more are awaiting detection.

Is anybody — or anything — there?

Satellites monitor how ‘greenness’ changes with Earth’s seasons. (NASA)

The hunt for life in these places, which are impossible to visit in person, will begin with a search for biological products in their atmospheres. These atmospheric fingerprints of life, called biosignatures, will be detected using next-generation telescopes that measure the composition of gases surrounding planets that are light years away.

It’s a tricky business, since biosignatures based on single measurements of atmospheric gases could be misleading. To complement these markers, and thanks to funding from the NASA Astrobiology Institute, scientists at the University of California, Riverside’s Alternative Earths Astrobiology Center are developing the first quantitative framework for dynamic biosignatures based on seasonal changes in the Earth’s atmosphere.

Titled “Atmospheric Seasonality As An Exoplanet Biosignature,” a paper describing the research was published today in The Astrophysical Journal Letters. The lead author is Stephanie Olson, a graduate student in UCR’s Department of Earth Sciences.

As Earth orbits the sun, its tilted axis means different regions receive more rays at different times of the year. The most visible signs of this phenomenon are changes in the weather and length of the days, but atmospheric composition is also impacted. For example, in the Northern Hemisphere, which contains most of the world’s vegetation, plant growth in summer results in noticeably lower levels of carbon dioxide in the atmosphere. The reverse is true for oxygen.

“Atmospheric seasonality is a promising biosignature because it is biologically modulated on Earth and is likely to occur on other inhabited worlds,” Olson said. “Inferring life based on seasonality wouldn’t require a detailed understanding of alien biochemistry because it arises as a biological response to seasonal changes in the environment, rather than as a consequence of a specific biological activity that might be unique to the Earth.” Further, extremely elliptical orbits rather than axis tilt could yield seasonality on extrasolar planets, or exoplanets, expanding the range of possible targets.

In the paper, the researchers identify the opportunities and pitfalls associated with characterizing the seasonal formation and destruction of oxygen, carbon dioxide, methane, and their detection using an imaging technique called spectroscopy. They also modeled fluctuations of atmospheric oxygen on a life-bearing planet with low oxygen content, like that of Earth billions of years ago. They found that ozone (O₃), which is produced in the atmosphere through reactions involving oxygen gas (O₂) produced by life, would be a more easily measurable marker for the seasonal variability in oxygen than O₂itself on weakly oxygenated planets.

“It’s really important that we accurately model these kinds of scenarios now, so the space and ground-based telescopes of the future can be designed to identify the most promising biosignatures,” said Edward Schwieterman, a NASA Postdoctoral Program fellow at UCR. “In the case of ozone, we would need telescopes to include ultraviolet capabilities to easily detect it.”

Schwieterman said the challenge in searching for life is the ambiguity of data collected from so far away. False positives — nonbiological processes that masquerade as life — and false negatives — life on a planet that produces few or no biosignatures — are both major concerns.

“Both oxygen and methane are promising biosignatures, but there are ways they can be produced without life,” Schwieterman said.

Olson said observing seasonal changes in oxygen or methane would be more informative.

“A potentially powerful way to assess exoplanets for inhabitation would be to observe their atmospheres throughout their orbits to see if we can detect changes in these biosignature gases over the course of a year,” she said. “In some circumstances, such changes would be difficult to explain without life and may even allow us to make progress towards characterizing, rather than simply recognizing, life on an exoplanet.”

Timothy Lyons, a professor of biogeochemistry in UCR’s Department of Earth Science and director of the Alternative Earths Astrobiology Center, said this work advances the fundamental approach to searching for life on very distant planets.

“We are particularly excited about the prospect of characterizing oxygen fluctuations at the low levels we would expect to find on an early version of Earth,” Lyons said. “Seasonal variations as revealed by ozone would be most readily detectable on a planet like Earth was billions of years ago, when most life was still microscopic and ocean dwelling.”

In addition to Olson, Schwieterman, and Lyons, the paper’s authors are Andy Ridgwell and Stephen Kane from UC Riverside, Christopher Reinhard from the Georgia Institute of Technology, and Victoria Meadows from the University of Washington. The work is funded by the NASA Astrobiology Institute and the National Science Foundation (NSF) Frontiers in Earth System Dynamics (FESD).

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Campus to celebrate 50th anniversary of historic Moon landing

Anonymous — Thu, 03 Sep 2020 22:32:22 +0000

Campus to celebrate 50th anniversary of historic Moon landing Anonymous (not verified) Thu, 09/03/2020 - 15:32 More News Iqbal Pittalwala | UCR News July 08, 2019

This year marks the 50th anniversary of the historic Apollo 11 Moon mission. To celebrate, the University of California, Riverside, is hosting a free public event on Thursday, July 11, from 6:30-9:30 p.m.

Attendees will have an opportunity to learn more about the Apollo 11 legacy, as well as current missions to our solar-system’s planets and moons. The event, which will take place in Pierce Lawn and the Life Sciences Building, will also feature telescope viewings of the moon, and multiple hands-on activities.

On July 16, 1969, astronauts Neil Armstrong, Buzz Aldrin, and Michael Collins lifted off from Earth on a journey to the moon. Four days later, Armstrong and Aldrin became the first humans to set foot on the lunar surface.

“Landing on the moon was probably the single most important achievement of humankind since the beginning of civilization,” said Bahram Mobasher, a professor of physics and observational astronomy. He’s an expert on the formation and evolution of galaxies and the search for the most distant ones. “This honor belongs to all humanity regardless of race, religion, or the country of the origin. It shows the power of our will and the strength of our desires — a clear demonstration of what science can do.”

Stephen Kane, an associate professor of planetary astrophysics, agrees that the moon landing represents a significant milestone in our advancement of our civilization.

“For the first time in history, we were finally free from being restricted to only walking upon our planet,” said Kane, an expert on the detection, characterization, and habitability of exoplanets. “However, the famous quote of the landing being a ‘giant leap for mankind’ is more than just about scientific progress. It was an event that truly unified humanity and provided a key moment of reflection on how we are all custodians of our beautiful island oasis in a vast universe, and we should never lose sight of that big picture.”

Hands-on activities, such as touching a Martian meteorite, understanding the phases and eclipses of the moon, and cratering experiments, will take place from 6:30-7:30 p.m. in the Life Sciences courtyard, and will resume at 8:30 p.m. along with telescope viewings in Pierce Lawn.

Timothy Lyons, a distinguished professor of biogeochemistry in the Department of Earth and Planetary Sciences, will give a talk titled “Fifty Years of Discovery — From the Moon to Mars and Beyond” in Life Sciences 1500.

No RSVP is required to attend the event. Complimentary parking will be available for attendees in Lot 6.

“The moon landing was the first and one of the greatest attempts at space exploration in the entire human history,” said event organizer Xinnan Du, a postdoctoral scholar and director of education and public outreach in the Department of Physics and Astronomy. “As a millennial, I’ve always been awed by the fact that humankind had already walked on the surface of another celestial object when technology was still barely part of everyday life. This anniversary is an amazing opportunity to not only celebrate the achievement we made 50 years ago, but also learn about how far we’ve come in exploring space: from the moon, to Mars, to Pluto, and the outer edge of the solar system.”

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Ancient meteorite site on Earth could reveal new clues about Mars’ past

Anonymous — Sat, 01 Aug 2020 02:57:56 +0000

Ancient meteorite site on Earth could reveal new clues about Mars’ past Anonymous (not verified) Fri, 07/31/2020 - 19:57 More News Jules Bernstein | UCR News February 26, 2020

Scientists have devised new analytical tools to break down the enigmatic history of Mars’ atmosphere — and whether life was once possible there.

A paper detailing the work was published today in the journal Science Advances. It could help astrobiologists understand the alkalinity, pH and nitrogen content of ancient waters on Mars, and by extension, the carbon dioxide composition of the planet’s ancient atmosphere.

Jezero Crater, landing site for the upcoming Mars 2020 rover mission. (NASA/JPL/JHUAPL/MSSS/Brown University)

Mars of today is too cold to have liquid water on its surface, a requirement for hosting life as we know it.

“The question that drives our interests isn’t whether there’s life on present-day Mars,” said Tim Lyons, UCR distinguished professor of biogeochemistry. “We are driven instead by asking whether there was life on Mars billions of years ago, which seems significantly more likely.”

However, “Overwhelming evidence exists that Mars had liquid water oceans roughly 4 billion years ago,” Lyons noted.

The central question astrobiologists ask is how that was possible. The red planet is farther from the sun than Earth is, and billions of years ago the sun generated less heat than it does today.

“To have made the planet warm enough for liquid surface water, its atmosphere would likely have needed an immense amount of greenhouse gas, carbon dioxide specifically,” explained Chris Tino, a UCR graduate student and co-first-author of the paper along with Eva Stüeken, a lecturer at the University of St. Andrews in Scotland.

Since sampling Mars’ atmosphere from billions of years ago to learn its carbon dioxide content is impossible, the team concluded that a site on Earth whose geology and chemistry bear similarities to the Martian surface might provide some of the missing pieces. They found it in southern Germany’s Nordlinger Ries crater.

A sample of suevite rock formed nearly 15 million years ago by the Ries Crater meteorite impact. Similarly impact-generated rocks exist on the rims of ancient crater lakes on Mars. (NASA)

Formed roughly 15 million years ago after being struck by a meteorite, Ries crater features layers of rocks and minerals better preserved than almost anywhere on Earth.

The Mars 2020 rover will land in a similarly structured, well-preserved ancient crater. Both places featured liquid water in their distant past, making their chemical compositions comparable.

According to Tino, it’s unlikely that ancient Mars had enough oxygen to have hosted complex life forms like humans or animals.

However, some microorganisms could have survived if ancient Martian water had both a neutral pH level and was highly alkaline. Those conditions imply sufficient carbon dioxide in the atmosphere — perhaps thousands of times more than what surrounds Earth today — to warm the planet and make liquid water possible.

While pH measures the concentration of hydrogen ions in a solution, alkalinity is a measure dependent on several ions and how they interact to stabilize pH.

“Ries crater rock samples have ratios of nitrogen isotopes that can best be explained by high pH,” Stüeken said. “What’s more, the minerals in the ancient sediments tell us that alkalinity was also very high.”

However, Martian samples with mineral indicators for high alkalinity and nitrogen isotope data pointing to relatively low pH would demand extremely high levels of carbon dioxide in the past atmosphere.

The resulting carbon dioxide estimates could help solve the long-standing mystery of how an ancient Mars located so far from a faint early sun could have been warm enough for surface oceans and perhaps life. How such high levels could have been maintained and what might have lived beneath them remain important questions.

“Before this study, it wasn’t clear that something as straightforward as nitrogen isotopes could be used to estimate the pH of ancient waters on Mars; pH is a key parameter in calculating the carbon dioxide in the atmosphere,” Tino said.

Funding for this study came from the NASA Astrobiology Institute, where Lyons leads the Alternative Earths team based at UCR.

Included in the study were Gernot Arp of the Georg-August University of Göttingen and Dietmar Jung of the Bavarian State Office for the Environment.

When samples from NASA’s Mars 2020 rover mission are brought back to Earth, they could be analyzed for their nitrogen isotope ratios. These data could confirm the team’s suspicion that very high levels of carbon dioxide made liquid water possible and maybe even some forms of microbial life long ago.

“It could be 10-20 years before samples are brought back to Earth,” Lyons said. “But I am delighted to know that we have perhaps helped to define one of the first questions to ask once these samples are distributed to labs in the U.S. and throughout the world.”

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