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2001 Annual Science Report

University of Colorado, Boulder Reporting  |  JUL 2000 – JUN 2001

Executive Summary

Executive Summary — CUB (dm)

University of Colorado Center for Astrobiology has supported the following general activities:

â?¢ Sponsored public symposium on “Is there intelligent life elsewhere?”.
â?¢ Sponsored graduate and undergraduate courses in astrobiology.
â?¢ Prepared proposal to the CU Graduate School for a Graduate Certificate in Astrobiology.
â?¢ CU filled a faculty position in astrobiology with Prof. Stephen Mojzsis in Dept. of Geological Sciences.
â?¢ Sponsored creation of an undergraduate “Astrobiology Society”.
â?¢ Sponsored monthly astrobiology colloquium and informal Co-Investigator research forum.

Research activities sponsored by the Center for Astrobiology using support from the NASA Astrobiology Institute included:

(i) Constraints on planet formation (John Bally, lead). We found compelling evidence for growth of dust grains in the outer portions of the largest protoplanetary disks in the Orion Nebula, providing insight into the very first stages of planet formation. Assessment of hazards of radiation and dynamical interactions for planet formation indicate that only 3-10 % of young stars will possess planetary systems.

(ii) Planetary climates (Brian Toon, lead). Thje efforts center on understanding processes that affect early climate on terrestrial planets. Results to date for Mars indicate (a) that impact release of crustal water may have played a substantial role in maintaining an early climate conducive to life and (b) that carbon dioxide clouds on Mars have radiative effects that make it difficult for them to contribute to the putative early greenhouse warming of Mars.

(iii) Setting the stage for the origin of life on Earth (Steve Mojzsis, lead). This is a new investigation this year, exploring the geological environment on early Earth and the relevance for the origin and early history of life on Earth. However, efforts within the last twelve months by this group included using 4.3-billion-year-old zircons to obtain evidence for extensive liquid water and weathering at or near the Earth’s surface at that time.

(iv) RNA world and origin of life (Mike Yarus, lead). We have made progress in developing techniques for Direct Isolation of Catalysts or Enzymes (DICE) and anticipate carrying out the first isolations this coming year. We have synthesized new Transition State Analogues (TSAs) for the ribosomal peptidyl transferase ribozyme, and begun a set of selections for RNAs that bind these compounds; we hope that these new selections will show that the peptidyl transferase itself (or some close relative) can emerge directly from randomized RNA sequences, which would support the RNA World hypothesis.

(v) Toward a molecular phylogeny of a metabolic enzyme, maleylacetoacetate isomerase (Shelley Copley, lead). This is a new task added this year. The goal is to use the enzyme maleylacetoacetate (MAA) isomerase to study the evolution of metabolic pathways and the spread of metabolic genes. MAA has a puzzling phylogenetic distribution, in which the distribution is patchy, as might be expected if the gene has been distributed by infrequent lateral transfer events or lost selectively in certain lineages.

(vi) Molecular analysis of microbial ecosystems in extreme environments (Norman Pace, lead). Projects center around development and use of rRNA-based molecular methods to survey and study the microbial constituents of ecosystems in extreme environments. Recent results include the discovery of seven new kingdom-level phylogenetic groups of eucaryotes in anaerobic environments and the identification of hydrogen (as opposed to sulfur) as the fundamental energy source for thermophilic communities in Yellowstone hot springs.

(vii) Symbiosis and the origin of multicellularity in photosynthetic organisms (William Friedman, lead). We are studying symbiosis in order to understand major events in the evolution of life on Earth, including, for example, the origin of multicellularity. Results include beginning to understand one of the most important symbioses in evolutionary history, the mycorrhizal (plant-fungus) association in early land plant lineages; and analyzing the role of these symbioses in the colonization of land by photosynthetic organisms.(viii) Energetics of life on other planets (Bruce Jakosky, lead). We are analyzing the geochemical environment of the surface and subsurface of Mars in order to determine the energy available from water-rock chemical reactions to support possible metabolism. Preliminary results have been obtained from models using the mineralogy and petrology of martian meteorites as constraints, and suggest that chemical energy is relatively limited due to the comparatively small contrast, by terrestrial standards, in oxidation state between groundwater and hydrothermal fluid.(ix) Philosophical issues in astrobiology (Carol Cleland, lead). We are exploring the nature of scientific investigations as applied to astrobiology, in order to better understand historical vs. experimental sciences and the implications for, for example, the search for life on Mars. Results are used to point out the problems inherent in the Viking biology experiments and the difficulty of reaching concrete conclusions from them(x) Societal issues in astrobiology (Bruce Jakosky, lead). We are using astrobiology as a way to understand the relationship between science and society, the importance of educating the public as to the nature of science (and, equally importantly, of non-science), and the role of science in society today.(xi.) We met the commitment in our initial proposal to hire a new faculty member in astrobiology, by hiring Dr. Stephen Mojzsis as Assistant Professor in the Dept. of Geological Sciences. His research specialty is in the environment on the early Earth and the implications for the origin and early evolution of life on Earth and for the potential for life elsewhere. He arrived on campus in January 2001.

We created an undergraduate “Astrobiology society” to engage undergraduates in the excitement and breadth of the field. We just created it in spring 2001, and have met to have telescope viewing of the planets and an informal talk on astrobiology by one of the CU Co-Is. Future activities will include talks by visitors, a field trip to a local outcrop of the K-T boundary layer, and a visit to Lockheed Martin to see spacecraft assembly and operations.

We prepared a proposal to the CU Graduate School to create a Graduate Certificate in Astrobiology. A graduate certificate is, in essence, the graduate equivalent of an undergraduate minor. We are going this way in lieu of creating a separate graduate degree in astrobiology, as the latter would serve to split students from their most natural intellectual home. Rather, a certificate provides added value to their degree with training in the broader aspects of astrobiology.

We sponsored teaching a graduate class in astrobiology (spring 2001), drawing some 16 students from both the physical and biological sciences.

We sponsored teaching an undergraduate non-majors class in “Extraterrestrial Life” (fall 2000 and spring 2001), each time drawing about 70 students from all majors around campus. CU provided teaching assistant support as part of its commitment to the astrobiology program.