Highlights of research conducted in the UCLA Center for Astrobiology over the past several years are listed below. This list is meant to be representative of the types of work completed. It is not a comprehensive publications list (publications lists are available in NAI annual reports).

• A distorted disk of cold dust surrounding the star Fomalhaut (25 light years from the Sun) demonstrates the existence of a large, Saturn-like planet around the star. This is direct evidence for the existence of the types of planets that maybe necessary for life in extrasolar planetary systems (Holland et al. 2003).

• Acquisition of new isotopic and phylogenetic evidence for the anaerobic use of methane by microbial consortia composed of sulfate-reducing bacteria and methane-consuming Archaea (Orphan et al. 2001).

• A model of mass-independent fractionation (MIF) of the three isotopes of oxygen was developed for the modern atmosphere that makes testable predictions about the distribution of MIF effects in different atmospheric molecules (Lyons 2001).

• The catalogue of youngest, nearest stars, such as the Beta Pictoris moving group (Zuckerman et al. 2001) was expanded to ~ 200 members as a result of ongoing observations of the southern skies at the Siding Springs observatory, Eastern Australia. Several of these stars (less than 30 million years old) are expected to have warm Jupiter-class planets that should be visible in the infrared using current technologies (e.g., the Hubble Space Telescope).

• A major survey using the near-infared spectrometer (NIRSPEC), designed and built at UCLA for the Keck Observatory (Mclean), obtained IR spectra of 62 brown dwarfs. The data obtained will provide a wealth of information for modeling the atmospheres of such cool objects.

• Laser-Raman spectral imaging of microscopic filaments from the 3.5 billion year old Apex chert was used to demonstrate their carbonaceous composition (Schopf et al. 2002). These filaments have been regarded as the world’s oldest microfossils, though controversy surrounds their origin.

• Sulfur isotopic evidence was found for atmospheric but not bacterial processes in the formation of early Archean sedimentary sulfides and sulfates (Runnegar et al. in preparation).

• Reorientation of transfer RNA molecules during protein synthesis may indicate how "proofreading" developed as life emerged from the RNA world (Simonson and Lake 2002).

• All living eukaryotes appear to have mitochondria or to have lost them during the course of evolution. Their last common ancestor must postdate the permanent symbiosis that created the aerobically energized eukaryotic cell from prokaryotic precursors (Roger and Silberman 2002).

• Using genes involved in development, an antecedent of the pituitary gland was identified in early-diverging metazoans (e.g., jellyfish). The pituitary is a relic of a light and gravity detecting structure that may represent the first step in the evolution of the complex sensory and neural organization that characterizes animals (Jacobs and Gates in prep.).

• Calculations showed that a chaotic transition in the dynamics of the inner Solar System around the end of the Cretaceous some 65 million years ago may have disturbed the inner part of the asteroid belt, thus increasing the likelihood of an asteroid hitting the Earth at that time (Varadi et al. 2001).

• Geological mapping of Akilia island, Greenland, confirms an age greater than 3.8 billion years for the oldest sedimentary rocks and the organic material contained within them (Manning et al. 2001).

• Detection of a massive population of asteroids around nearby star z Leporis (Jura and Chen 2001).

• Ocean-continental crust interactions approximately 4.3 billion years ago on Earth are evidenced by the isotopic compositions of very old zircon crystals from Western Australia (Mojzsis et al. 2001).

• Horizontal gene transfer is limited by the complexity of gene product interactions (Lake et al. 2000).

• Planetary atmospheres may not be significantly eroded by giant impacts (Newman et al. 1999).

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Current areas of research:
(1) Extrasolar Planetary Systems
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(2) Habitability within the Solar System
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(3) Earth's Early Environment and Life
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(4) Evolution of Biological Complexity
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