October 2008

The latest version of NASA's Astrobiology Roadmap and exciting reports on new strategies for detecting biosignatures in Earth rocks highlight the diverse content of the August 2008 (Volume 8, Number 4) issue of Astrobiology, a peer-reviewed journal published by Mary Ann Liebert, Inc. The latest version of NASAs Astrobiology Roadmap, a comprehensive document intended to guide and integrate research and technology development across groups from academia, government, and private institutions, is highlighted in this issue. The Roadmap defines research objectives aimed at answering three main questions: how does life begin and evolve; does life exist elsewhere in the universe; and what is the future of life on Earth and beyond?

Contents below

The NAI supports postdoctoral fellows hosted at NAI teams through the NASA Postdoctoral Program (NPP). The NPP provides talented postdoctoral scientists and engineers with valuable opportunities to engage in ongoing NASA research programs and serves as a source of talent to ensure the continued quality of the NASA research workforce. The deadline for the next round of applications is November 1. For more information on the program, please see and .

As a reminder, all current NAI advisors, from CAN 3 and CAN 4 teams, are eligible as advisors to host postdoctoral fellows.

Source: NAI Newsletter

Researchers from NAI's University of Arizona team and their colleagues at the University of Leeds have a new paper in Angewandte Chemie International Edition dealing with prebiotic chemistry and the early Earth. Working both experimentally and with models of the early atmosphere, the team shows that the Hadean and early Archaean Earth was primed with an abundance of condensed phosphates, enabling the formation of the necessary precursors of RNA and DNA. This research removes one of the large stumbling blocks in prebiotic chemistry- that the early Earth lacked a low-temperature reservoir of activated phosphate compounds capable of eventually leading to the origin of life.

Source: NAI Newsletter

Members of NAI's Penn State, Carnegie Institution, and MIT teams report in a recent issue of Earth and Planetary Science Letters, the distribution of biomarkers in 2.72-2.56 billion-year-old, Neoarchean rocks from the Hamersley Province on the Pilbara Craton in Western Australia. Their observations are consistent with a cyanobacterial source for 2-methylhopanes, in which cyanobacteria were likely the cornerstone of microbial communities in shallow-water ecosystems providing molecular oxygen, fixed carbon, and possibly fixed nitrogen.

Their data, revealing relative abundances of 3-methylhopanes, but not 2-methylhopanes, strongly correlate to stable carbon isotopic composition of insoluble particulate organic matter (kerogen). The unanticipated nature of this relationship provides evidence for a shallow-water locus of carbon cycling through aerobic oxidation of methane and, coincidentally, a means to demonstrate biomarker syngenicity.

Source: NAI Newsletter

Researchers from NAI's University of Hawai'i team have a paper in the September 17 edition of Nature about the evolution of the animal gut. For more than 100 years zoologists have speculated about scenarios of how the bilaterally symmetrical animals (animals that have a left and a right side, like flies, fish, and humans) evolved from a simple circular (radially symmetric) ancestor that looked similar to jelly fish or corals. In the commonly presented scenarios this transition is connected to the evolution of a through-gut with an anterior mouth and posterior anus. It has been thought that both openings emerged simultaneously from a single embryological opening through which the inner tissues enter (called blastopore).

Astrophysicists from the NAI's Carnegie Institution of Washington team and their colleagues have shown for the first time that a supernova could have triggered the solar system's formation under conditions of rapid heating and cooling. For several decades, scientists have thought that the solar system formed as a result of a shock wave from an exploding star--a supernova--that triggered the collapse of a dense, dusty gas cloud that contracted to form the sun and the planets. But detailed models of this formation process have only worked under the simplifying assumption that the temperatures during the violent events remained constant. The results, published in the October 20, 2008, issue of the Astrophysical Journal, have resolved this long-standing debate.

Source: NAI Newsletter

Presenter: Rory Barnes
Date/Time: October 7, 2008 02:30 PM Pacific

Abstract: The first terrestrial-like exoplanets will likely be observed in tight orbits around low-mass stars. Conveniently, planets on these orbits receive about as much starlight as the Earth does from the Sun, and hence have to potential to be habitable. Such planets may also experience significant tidal forces from the star which can result in orbital decay, a specific planetary rotation, and significant internal heating. I describe how these phenomena are likely to impact habitability. In some cases orbital decay may result in planets moving too close to their star for habitability. For planets on non-circular orbits, rotation periods may be similar to the Earth's and hence may produce similar atmospheric circulation patterns.

NASA has awarded five-year grants, averaging $7 million each, to 10 research teams from across the country to study the origins, evolution, distribution, and future of life in the universe.

The interdisciplinary teams will become new members of the NASA Astrobiology Institute, located at NASA's Ames Research Center at Moffett Field, Calif. Teams from the University of Hawaii in Honolulu; Arizona State University in Tempe; the Carnegie Institution of Washington; Pennsylvania State University in University Park, Pa.; the Georgia Institute of Technology in Atlanta; and Rensselaer Polytechnic Institute in Troy, N.Y., have been selected as members. Teams from Ames, NASA's Goddard Space Flight Center in Greenbelt, Md., and two teams led by NASA's Jet Propulsion Laboratory in Pasadena, Calif., also have been selected.

Salle Cassini, Observatoire de Paris, November 19-21 2008

Exoplanets are being discovered at an ever accelerating pace. As a result planetary scientists and astronomers are increasingly called upon to make the transition from discovery to characterization, so that we can begin the long journey of understanding these planets in the same way that we understand those in our own Solar System. Among the known exoplanets, hot-Jupiters and hot-Neptunes that transit their parent stars present the first real opportunities to determine key compositional and atmospheric parameters.