Earth, Sky and Astrobiology
Excerpts from February 21 Earth and Sky radio interview with Dr. Runnegar, a paleontologist at the University of California, Los Angeles and the incoming 2003 director of NASA’s Astrobiology Institute
|The icy cracks of Jupiter’s moon Europa continue to intrigue astrobiologists. The overall white sheen is likely frost and the moon’s heat source is a combination of an underground ocean and tidal heating under the strong gravitational pull of Jupiter. Credit: Galileo Project, JPL, NASA|
Deborah Byrd: This is Earth and Sky. Astrobiology is the study of life in space — including here on Earth. Bruce Runnegar at UCLA is incoming director of NASA’s Astrobiology Institute. He says astrobiology’s goal is to answer three basic questions.
Bruce Runnegar: First one is — are we alone? — that is, are we the only kind of life in the universe? . . . Second question is — how did life originate on Earth? . . . And perhaps even more important — for most of what we regard as civilization anyway — is what are we going to do with our own life in future?
Deborah Byrd: Astrobiologists like Runnegar are trying to understand how conditions on Earth four billion years ago could have spawned life. Others study Mars or the moons of Jupiter and Saturn to see if life could survive there. Astronomers look for other solar systems with Earth-like planets. Yet another branch of the field is considering how human space colonies might work.
Bruce Runnegar: Are we going to be responsible when we go to the moon and Mars? What are we going to take with us? How are we going to protect those planets? Are we going to develop them like the Los Angeles basin? So astrobiology is forward looking as well as backward looking.
|Dr. Bruce Runnegar, UCLA Department of Earth and Space Sciences, Los Angeles|
"Well I guess, there’s pretty well every kind of scientist you can imagine involved in astrobiology. And so mathematicians might be somebody who you wouldn’t really expect. But they are important in modeling processes such as what might be habitable around a nearby star — where the habitable zone is because of the dynamics of the planets which we’re now discovering which are in orbits that we didn’t expect. So mathematics are very important. Modeling other things as well …"
earthsky.org: Why does Astrobiology matter?
Bruce Runnegar: "I guess that’s because that’s what people want to know and there are many people in the community, in this community and the global community who want to know the answer to these questions that I started with in the beginning. Where did we come from? How did we originate? Now they may not see the money spent in quite the way that I described. But this is the way to answer these questions. "
". . . so astrobiology is something that any civilization worth its salt should do, provided it can afford to do so."
Established in July 1998, the NASA Astrobiology Institute (NAI) is a virtual organization composed of NASA field centers, universities and research organizations that collaborate to study the origin, evolution, distribution and future of life in the universe. The Institute brings together astronomers, biologists, chemists, geologists, paleontologists, physicists and planetary scientists. It comprises 15 lead teams selected from competitive, peer-reviewed proposals submitted in response to NASA Cooperative Agreement Notices or CANs. Leadership of the Institute, the Director’s office and associated staff are located at NASA Ames. NAI’s first director was G. Scott Hubbard, followed by Blumberg in 1999.
|The haze of an atmospheric layer on Saturn’s moon, Titan. With an atmosphere thicker than Earth’s, and composed of many biochemically interesting molecules (methane, hydrogen and carbon), Titan’s rich chemistry will continue to interest astrobiologists as they look forward to landing a probe on its surface in 2004-5. Credit: Voyager Project, JPL, NASA|
The past few years have witnessed the discovery of planets around other stars, strong circumstantial evidence for a liquid water ocean beneath the surface of Jupiter’s moons Europa, Ganymede, and Callisto, controversial claims for biological activity in a martian meteorite, the discovery of life in extreme terrestrial environments, and a genuine revolution in our understanding and manipulation of the genetic mechanisms of the living cell.
Significant scientific advances have occurred in the past 5 years in addressing some of the questions identified in the astrobiology roadmap. A few example areas that have borne particular fruit, with example references include the following:
- Analysis of complex organic chemistry in interstellar clouds of gas and dust that give rise to new stars and solar systems;
- Direct study of extrasolar giant planets through transits and spectra;
- Discovery that living organisms, normally found on Earth’s surface, can survive at extreme pressure;
- Evidence from geologic features that liquid water once flowed on the surface of the planet Mars;
- Indications from magnetic field geometry that liquid water likely exists today below the icy crust of Jupiter’s moon Europa;
- Ground-based studies of Titan indicating both temporal and spatial variability, and the presence of organic molecules;
- Chemical-isotopic hints that microbial life on Earth existed 3.9 billion years ago, almost to the period of early heavy cometary bombardment;
- Evidence that liquid water existed in the crust of the Earth some 4.3 billion years ago;
- Elucidation of the detailed history of evolution and the phylogenetic relationships among organisms; and
- In vitro evolution experiments that have come close to developing self-replicating systems in the laboratory.
The mix of flight programs, which run from Discovery missions (e.g., Mars Pathfinder, Near-Earth Asteroid Rendezvous, and Stardust) through to flagship mission (e.g., Galileo and Cassini), provides a varied tapestry of flight-preparation times, risks, and rewards.
Notable among these has been the spectacular exploration of the outer solar system, commencing with the Pioneer missions, through the Voyager discoveries about the satellite systems of the giant planets, and culminating in the Galileo discoveries about Europa and the promise of Cassini discoveries at Saturn.
Runnegar and his wife, Maria, a biochemist at the University of Southern California, have one daughter, who is a lawyer in Brisbane, Australia. He enjoys geological fieldwork, old furniture and botanical gardens.
The NAI currently has 15 member institutions: Arizona State University, Tempe; University of Colorado, Boulder; University of Washington, Seattle; NASA Ames Research Center; Scripps Research Institute, La Jolla, Calif.; University of Rhode Island; Pennsylvania State University; Harvard University; University of California, Los Angeles; Michigan State University; Marine Biological Laboratory, Woods Hole, Mass.; Carnegie Institution of Washington; NASA Johnson Space Center, Houston; and two research teams located at the NASA Jet Propulsion Laboratory, Pasadena, Calif.
Related Web Pages
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 D. Charbonneau, T.M. Brown, R.W. Noyes, and R.L. Gilliland, "Detection of An Extrasolar Planet Atmosphere," Astrophysical Journal 568: 377-384, 2002.
 A. Sharma, J.H. Scott, G.D. Cody, M.L. Fogel, R.M. Hazen, R.J. Hemley, and W.T. Huntress, "Microbial Activity at Gigapascal Pressures," Science 295: 1514-1516, 2002
 V.R. Baker, "Water and the Martian Landscape," Nature 412: 228-236, 2001.
 M.G. Kivelson, K.K. Khurana, C.T. Russell, M. Volwerk, R.J. Walker, and C. Zimmer,"Galileo Magnetometer Measurements: A Stronger Case for a Subsurface Ocean at Europa," Science 289: 1340-1341, 2000.
 R. Meier, B.A. Smith, T.C. Owen, and R. Terrile, "The Surface of Titan from NICMOS Observations with the Hubble Space Telescope," Icarus 145: 462-473, 2000.
 S.J. Mojzsis, G Arrhenius, K.D. McKeegan, T.M. Harrison, A.P. Nutman, and C.R.L. Friend, "Evidence for Life on Earth Before 3,800 Million Years Ago," Nature 384: 55-59, 1996.
 S.J. Mojzsis, T.M. Harrison, and R.T. Pidgeon, "Oxygen-Isotope Evidence from Ancient Zircons for Liquid Water at the Earth’s Surface 4,300 Myr Ago," Nature 409: 178-181, 2002.
 N.R. Pace, "A Molecular View of Microbial Diversity and the Biosphere," Science 276: 734-740, 1997.
 S.J. Butcher, J.M. Grimes, E.V. Makeyev, D.H. Bamford, and D.I. Stuart, "A Mechanism for Initiating RNA-Dependent RNA Polymerization," Nature 410: 235-240, 2001.