2014 Annual Science Report
Rensselaer Polytechnic Institute Reporting | SEP 2013 – DEC 2014
Our investigators are members of the New York Center for Astrobiology (NYCA; www.origins.rpi.edu), based at Rensselaer Polytechnic Institute (RPI) in partnership with Syracuse University, the University at Albany, the University of Arizona, and Albion College. Our research is devoted to elucidating the origins of both life itself and of habitable planetary environments, in our own Solar System and in planet-forming regions around other stars: in short, to develop realistic, widely applicable models for the emergence of molecular complexity leading to life. This is being accomplished through a synergy of interdisciplinary research that unifies astronomical observations, laboratory experiments and computational modeling. It addresses several goals of the Astrobiology Roadmap, including Goal 1 (potential for habitable planets), Goal 2 (life in our Solar System), Goal 3 (origins of life), Goal 4 (Earth’s early biosphere and environment), and Goal 7 (signatures of life).
An online newsfeed summarizing some highlights and accomplishments of our team may be found here: http://douglaswhittet.net/news/
Progress of Graduate and Undergraduate Researchers
Our team has continued to fulfill its role as a training center for STEM-discipline graduate and undergraduate students with interests in astrobiology, maintaining a long tradition of mentoring outstanding young scientists who become future professionals in a wide range of fields relevant to NASA. Three NAI-supported RPI graduate students successfully defended their doctoral theses during the reporting period:
*Raymond Menzel: “Multifluid Magnetohydrodynamics of Weakly Ionized Plasmas” (adviser: Wayne Roberge)
*Emily Hardegree-Ullman: “Probing the Chemical Environments of Early Star Formation: A Multidisciplinary Approach” (adviser: Doug Whittet)
*Lauren Cassidy: “Astrobiological Implications of Guanosine Gels and Analysis of Abiotic RNA Polymerization” (adviser: Linda McGown)
RPI undergraduate Physics major Emily Wislowsky was selected by the Universities Space Research Association as the recipient of the 2014 James B. Willett Educational Memorial Scholarship Award. Wislowsky, who was selected from a large number of applicants in a highly competitive selection, received the award for NAI-sponsored research (adviser: Doug Whittet) on the distribution of ices and organic molecules in regions of current star and planet formation. Her research is based on analysis of data from the NASA Spitzer Space Telescope. The award honors the late James B. Willet (1940-1998), a noted NASA astrophysicist at the Jet Propulsion Laboratory who also served as the manager of the Galileo mission to Jupiter.
During summer 2014 two undergraduates from Delaware State University, Jeremi Frazier and Arthur Newell, visited RPI with their adviser, Pablo Suarez, to work with Wayne Roberge on numerical approaches to shock models for chemical evolution in the discs and envelopes of young stellar objects. This project was seeded by an award to Suarez of an NAI-sponsored Minority Institution Research Support (MIRS) fellowship.
AbGradCon, Astrobiology Research Focus Group, and FameLab
Our team was proud to host the 2014 Astrobiology Graduate Conference (AbGradCon) at the RPI campus from July 27-31. The conference was held in conjunction with the fifth annual Astrobiology Research Focus Group (July 25-27) hosted at RPI’s Darrin Freshwater Institute, Lake George, New York. AbGradCon also hosted the kickoff to Season 3 of the science communications event FameLab: Exploring Earth and Beyond, which took place on July 29. Graduate students from around the country gathered to learn how to communicate their scientific research in a way that still includes the technical aspects while making it relatable to a general audience. Participants developed 3-minute, powerpoint-free presentations on their chosen topic. A preliminary round narrowed the field down to nine finalists who competed for the title of FameLab champion in front of a public audience at RPI’s Electronic Media and Performing Arts Center (EMPAC) theater in the evening. The winner, Graham Lau, who described his near-death research experience with an unstable sulphurous glacier, proceeds to compete for the national title in Washington, D.C.
Our team has transcended the confinements of individual disciplines in our approach to the questions of how life originated on Earth and whether it may have emerged elsewhere. We regard these questions as inseparable – only by understanding the confluence of circumstances that led to life on Earth can we realistically assess the probability of its origin elsewhere – and we not only recognize but also implement the interdisciplinary synergy that is essential for progress. Team members are interactive and interdisciplinary in their approach to science, bringing depth in each of our own fields to the common question of the origins of life. Our research is grouped into seven strongly interconnected and synergistic projects that form a logical organic sequence, from interstellar precursors through protoplanetary disks and the solar nebula to the early Earth and Mars. Some highlights are summarized here; further details may be found in the individual project reports and publications.
New stars and planetary systems are born within cold and relatively dense regions of the interstellar medium. To help us better understand the origins of our own solar system, and the myriad of others now known to exist, astronomers study interstellar clouds at the evolutionary phase immediately preceding stellar birth. In previous years we have reported results that (i) demonstrate the formation of water-ice and other volatiles on submicron-sized mineral grains in these clouds, and (ii) assess a long-standing problem in accounting for the distribution of elemental oxygen in both prestellar clouds and more diffuse regions of the interstellar medium. Our most recent work links these findings and shows that the first steps toward planet formation may occur much earlier in the star formation process than was previously supposed. We show that the most probable solution to the “missing oxygen” problem is the presence of grains coated with icy mantles that have grown to sizes an order of magnitude larger than typical interstellar grains.
The range of environments available on newly formed planets in the habitable zones of stars is likely to govern the rate and progress of chemical evolution that might lead to life. Our team studies minerals that may carry information on the environments in which they formed in our solar system. These include ancient terrestrial minerals such as zircons that provide windows into the Hadean Earth, lunar glasses that provide insight into the impact history of the Moon (and hence the Earth), and also terrestrial analogs of Martian minerals that we study to test their potential for future in-situ analysis and sample-return missions. All of this work is dependent on the availability of reliable geochronometers by which to date the samples. For example, the diffusive loss of argon from lunar impact glasses has the potential to compromise glass ages inferred by 40Ar/39Ar dating, and our team is conducting an extensive investigation of this problem. A key component of the study is the ability to carry out realistic numerical simulations of diffusive loss, and this would not have been possible without the NAI-instigated collaboration between the geoscientists in our team (Baldwin, Watson, et al.) and an expert in computational modeling (Roberge).
In our RNA World research, we are focused on exploring the role of the abundant and diverse geology and mineralogy of early Earth in prebiotic chemistry. This is a road not easily taken by teams of investigators trained in traditional chemical synthesis and biochemistry, yet it is difficult to ignore the fact that early Earth was dominated by dynamic surface and subsurface geochemical microenvironments in contact with early Earth’s water and the relatively sparse organic molecules needed for prebiotic chemistry. As an interdisciplinary team, we look for solutions to the many hurdles encountered in the prebiotic chemistry leading to RNA in the massive inorganic material of Earth’s surface and subsurface. In our approach, rather than behaving merely as a passive “container” or vessel for prebiotic chemistry, Earth’s crust is considered as a dynamic participant in early Earth chemistry that played an integral role in prebiotic synthesis through geologic processes. By understanding the chemistry of biomolecular precursors at the interface of rock and water, we develop new insight into plausible pathways to an RNA World that will allow us to refine origins hypotheses.
Our research places prebiotic chemistry firmly in the geochemical and mineralogical context of early Earth in both surface and deep ocean hydrothermal vent environments. The recent astrobiology hire of geomicrobiologist Karyn Rogers rounds out our team with a connection to hydrothermal vent environments and limits of habitability in deep-ocean and surface volcanic environments. In a new development of this work, we are constructing laboratory “chimney” analogs of deep ocean hydrothermal vents, and studying RNA polymerization in these chimneys, focusing on the effects of various mineralogical, physical and chemical variables on the RNA polymerization products. Some researchers have dismissed the possibility of an RNA World in these deep ocean environments because of concerns about the stability of RNA, but this ignores the potential effects of pressure, temperature, mineralogy and redox, which in turn will affect other variables such as pH, activity of water and molecular self-assembly. Building on these experiments, we are currently performing experiments designed to test the effects of deep ocean pressures, hydrothermal mineralogy and geochemistry on polymerization and reversible self-assembly of RNA nucleotides – self-assembly is a key consideration that may compete with, or possibly facilitate, polymerization. These experiments are a direct outgrowth of NAI support to our team that brought together expertise in RNA polymerization (McGown, Joshi), nucleotide self- assembly (McGown), early Earth geochemistry (Watson), high-pressure experimentation (Watson, Rogers), and hydrothermal vent environments (Rogers).
These research projects are just a sampling of the many interdisciplinary projects we have developed as a direct result of our collaborative environment. It is difficult to fully capture the enthusiasm and excitement generated by our discussions across disciplines at all levels, from faculty to postdocs, graduate students and undergraduates. Every idea is welcomed, every question is treated with respect, and every voice is heard. Sometimes it is the questions of those least familiar with the topic under discussion that lead to the most important insights and lines of inquiry. We all recognize the importance and impact of the NYCA in our research programs and are grateful for the opportunity to work together in this remarkable endeavor.