2011 Annual Science Report
Rensselaer Polytechnic Institute Reporting | SEP 2010 – AUG 2011
Our NAI scientists are members of the New York Center for Astrobiology (NYCA; http://www.origins.rpi.edu/), based at Rensselaer Polytechnic Institute (RPI) in partnership with the University at Albany, Syracuse University, the University of Arizona, and the University of North Dakota. Our team joined the NAI in Spring 2009, following the selection of our CAN5 proposal “Setting the stage for life: From interstellar clouds to early Earth and Mars”. 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: our long-term goal is 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.
Our team is also fully committed to delivering education and training in astrobiology of the highest quality. We are motivated by the national need to attract students to the Science, Technology, Engineering, and Mathematics (STEM) disciplines, and by the opportunities that astrobiology provides to accomplish this. We are also motivated by the need identified in the National Research Council (2008) report on the progress of the NAI, which stated (p. 46) that “to grow properly into a new science discipline, astrobiology will require the establishment of formal educational and training programs to support the evolution and transformation of this nascent field.” Our goal is thus to establish an effective program of educational and training that makes real, quantifiable contributions at all levels, from K–12 through undergraduate, graduate and postdoctoral.
Another goal of our team that influences is role in both research and education is to promote true and effective communication and collaboration across the scientific disciplines. The progress of scientific discovery typically advances in incremental steps, individually small but with potential to become collectively more than the sum of their parts. This is especially true of an interdisciplinary science, where connections between individual steps may be less obvious than in a single discipline. Our team has developed effective strategies to optimize integration. Several members of our team have a long history of working together in an interdisciplinary setting, and our younger researchers have been inducted into this culture. In-house research discussion meetings (2 per month) involving all members of the NYCA (with videocon links to our partner campuses) are the primary forum by which we promote integration, ensuring that all members are vested in the collective “big picture” goals of the center rather than merely working in isolation within their own subgroups. Our graduate students have also helped to instigate a national journal club for astrobiology spanning multiple NAI teams.
The Spring 2011 issue of the Rensselaer Alumni Magazine featured a full-length article on the New York Center for Astrobiology, available online at this address:
Our research is grouped into nine projects that form a logical sequence, from interstellar precursors through protoplanetary disks and the solar nebula to the surfaces of the early Earth and Mars. The number of projects has increased compared with last year, with the emergence of two new projects, “Survival of sugars in ice/mineral mixtures on high velocity impact” (led by Nicolle Zellner and funded by a DDF award) and “Microenvironmental influences on prebiotic synthesis” (led by Linda McGown, an offshoot of her previous work on the prebiotic chemical catalysis project). At this point in time, approximately at the mid-point of our 5-year cycle, I believe the research program of our team has reached maturity. Of course, we continue to develop and grow (e.g., by the emergence of the new projects noted above and by the addition of terahertz spectroscopy to our armory of techniques), whilst simultaneously ramping up our impact through significant new results and publications that build upon cumulative effort.
The remainder of this section highlights some important results and developments in our research, along the path from interstellar clouds to nascent planetary surfaces. For more detailed discussion, see the individual reports and listed publications.
The quality and quantity of the organic endowment of emerging solar systems depends on the chemical pathways that convert atoms and simple molecules such as H, O, OH, CO to the much more complex species detected in comets and meteorites. Methanol (CH3OH) is an important intermediary because it can be formed by surface catalysis on dust at interstellar temperatures, and is readily converted into larger organic molecules (HCOOCH3, CH3CHO, CH3OCH3, ...) by endothermic processes that may be activated when stars form in interstellar clouds. Our work has contributed to a clearer understanding of the nature and distribution of environments conducive to efficient CH3OH formation, suggesting the existence of “sweet spots” for organic synthesis in the circumstellar disks of certain protostars. A paper on this work (Whittet et al. 2011) was accepted for publication and has received considerable media attention following an RPI press release, picked up by a number of on-line national science news feeds, including Discovery, Space Daily and Astrobiology Magazine, and by the British (BBC) Sky at Night Magazine.
The next step along the evolutionary path occurs in protoplanetary disks such as that of our own Solar System. The temperature profile of the disk is vital. It seems well established that much of the organic matter in meteorites was synthesized by aqueous processes enabled by heating of the asteroidal parent bodies, but the dominant source of heat remains controversial. Fundamental new work by Roberge & Manzel has shown that the theory of electrodynamic induction heating, as presented in previous literature, is flawed and requires revision. A new model for asteroid heating is being developed and is likely to result in a significant paradigm shift in this area of research.
The ability of sugars and other prebiotic molecules to survive impact delivery to Earth is being investigated by Nicolle Zellner and collaborators in a joint project between NYCA and the JPL Icy Worlds team. Although still at an early state of development this project is already making rapid progress, with projectile impact experiments completed using facilities at NASA Ames Research Center and NASA Johnson Space Center. This project was selected for generous funding from the NAI Director’s Discretionary Fund in 2011.
The Early Earth project led by Bruce Watson has produced both an outstanding doctoral thesis and a notable journal publication during the year. Dustin Trail defended his thesis on December 3, 2010, making use of the RPI-NAI videoconferencing facility to broadcast the public part of his defense to co-investigators at Syracuse University (see image), and to allow a committee member at Syracuse to participate in the examination remotely. In a paper now in press for Nature, Trail, Watson & Tailby discuss the results of their study of the oxidation state of the formation environment of ancient zircon crystals, and deduce that the atmospheric gases emanating from volcanoes were non-reducing (i.e., bearing carbon in the form of CO2 rather than CH4) as long as 4.35 Ga ago. Their findings extend to earlier times previous work by Delano (2001) that had drawn the same conclusion based on geochemical studies of igneous rocks dated at 3.5 – 3.8 Ga. This result has major implications for Miller-Urey-type organic synthesis in the early atmosphere. Indeed, it provides indirect but persuasive support for alternative sources of organics on the early Earth, such as accretion of interplanetary debris or processes in hydrothermal systems.
The prebiotic chemistry team led by Jim Ferris has a long history of seminal research on RNA synthesis and polymerization by catalytic processes on montmorillonite clays and other minerals. Recent research focuses on revealing the sensitivity of catalytic activity to salinity and investigating the potential of clay catalysis for homochiral selectivity. Undergraduate student Brittany Ferraro’s research project identified a selective influence of salts on the oligomerization reactions attributed to hydrophilic and hydrophobic interactions in prebiotic RNA synthesis (work that resulted in her award of 1st prize out of 47 entries in the RPI Undergraduate Research Symposium poster competition). Research published by Joshi et al. (2011) suggests that montmorillonite may not only catalyze the synthesis of RNA but also facilitate homochiral selection, producing chirally pure oligomers of significant length at far higher abundances than expected by chance association. Important progress has also been made in the quest to characterize the geological contexts in which formation of catalytic vs. non-catalytic clays occurred. Results show that a narrow range of both chemical compositions and geologic settings are associated with clays observed to be excellent catalysts for RNA polymerization.
In an exciting new development, the Ferris group is collaborating with members of the Center for Terahertz Research at RPI to apply the technique of THz spectroscopy to studies of the interactions between minerals and biomolecules. This new collaboration is notable for several reasons: it engages physicists Wilke and Nayak in astrobiology research for the first time, and it opens up a new window for study of the properties of catalytic clays, building on previous work by our team. On a larger canvas it has broader potential: we envisage that THz spectroscopy may develop into a valuable general tool for non-destructive subsurface characterization of biomarkers in rocks and soils on planetary surfaces. With luck and support it could become an entire new subfield of astrobiology that we might term “terahertz astrobiomineralogy”. This idea was presented as a proposal to the NAI Director’s Discretionary Fund in 2011 (decision pending).
Preparation for Mars sample return is another important goal of our team and another area in which important progress has been made in the past year. In a paper recently published in Earth & Planetary Science Letters, Baldwin & Kula (Syracuse University) investigate the potential of jarosite as a marker of the chronology and conditions under which water was present on Mars. On Earth, jarosite can only form in the presence of water, so detection by the Opportunity Rover of its presence on Mars implies that water existed there at some point in the past; hence the collection and dating of jarosite from strategic locations on the surface of Mars could build a picture of the history of the putative Martian hydrosphere. Argon dating will be used to estimate the ages of the samples. The key result from our study of terrestrial analogs is to show that over timescales of order the age of the Solar System and at temperatures of 20°C or less, jarosite is stable against diffusive loss of argon: it thus preserves a reliable measure of its age as well as the climatic conditions that existed at the time it formed. This work was featured in a press release from Syracuse University, picked up by several on-line national science news feeds in October 2011 and highlighted on the NAI website.
Education and Public Outreach
Our education and public outreach program is led by John Delano (U Albany) in close collaboration with other members of our faculty team. EPO partners include the Association for the Cooperative Advancement of Science Education (ACASE) in Saratoga Springs, the ExxonMobil Bernard Harris Summer Science Camp (EMBHSSC), and WAMC Northeast Public Radio (Albany, NY). Other key members of our EPO team include Cynthia Smith (Assistant Dean of Students and EMBHSSC director at RPI) and Paul Mayeur (RPI graduate student specializing in science education).
Our education program includes several distinct but related activities described in detail in the individual project reports. By analogy with our science projects that follow the path of emerging complexity from small molecules in interstellar space to biomolecules on planetary surfaces, our education program aims to promote astrobiology at a progression of levels from K–12 though undergraduate courses to the training of future professionals in the field. Our Summer Science Camp is effectively a recruitment tool to STEM disciplines and an opportunity to enthuse students about astrobiology at an early age. Our Astrobiology Teachers Academy provides a mechanism by which we can reach out to high-school students, effectively recruiting their teachers as our partners, at a time when those students are making decisions about college applications. At the college level, our astrobiology-related courses and undergraduate research opportunities fulfill two distinct roles: they provide an introduction to the science of astrobiology for students with a general interest (and/or a need to fulfill science elective requirements), and they also provide a springboard for those interested in proceeding to the next level and considering graduate school in this or a related field. Finally, our astrobiology series on the National Public Radio show “The Best of Our Knowledge” is a showcase for the NAI and for all our Center activities, featuring both educational opportunities and ongoing research at a level accessible to the general public. Excellent progress has been made in the last year in all of these activities (please refer to the individual reports).
An important feature of our education program is our commitment to continuous evaluation and optimization. This aspect of EPO was part of the discussion at the NAI Education and Public Outreach session led by Daniella Scalice at the September 2011 Executive Council meeting at Green Lake, and it appears that our team may be setting a trend for others to follow. A significant change to our operations in the past year that arose from the evaluation process was the implementation of a new strategy to enhance the effectiveness of our Astrobiology Teachers Academy (ATA). Launched in summer 2009, the ATA is an annual 4-day event for a group of typically 10-15 high-school science teachers, hosted at RPI and independently evaluated by an external consultant (Paul Zachos of ACASE). The event itself has been consistently well received, but a concern was raised (see last year’s report) on the level of follow-through by teachers in bringing astrobiology to their classrooms. With the aid of an augmentation grant from NAI, awarded in 2010/11, we have put in place a system of incentives that include stipends for teachers, together with travel support and funding for supply teachers to cover for Academy teachers when they attend follow-up meetings and special events. This strategy has proved to be a success. Most teachers who joined the Academy in summer 2010 sustained their participation throughout the 2010/11 academic year with measurable outcomes in developing and implementing teaching modules. One teacher brought her entire class to an Astrobiology seminar at RPI in Spring 2011 to hear Natalie Batalha’s talk “Catching Shadows: Kepler’s Year-Two Transit Census”. Another major outcome was that five teachers from the 2010 ATA returned in summer 2011 as teacher-mentors. The NAI scientists and teacher-mentors thus became a team, combining their varied and complementary experience as educators for the benefit of the next group of teachers to join the program. We will continue this strategy next year and we have plans to support selected teachers to attend AbSciCon in 2012. John Delano and Paul Zachos will make a detailed presentation at a future NAI EPO telecon meeting on the progress of the ATA.