GLOBAL ECONOMIC VIEWPOINT
THE FRONTIERS OF ASTROBIOLOGY: NASA LOOKS FOR LIFE IN THE COSMOS
By Baruch S. Blumberg
Baruch S. Blumberg is director of the NASA Astrobiology Institute based at Moffett Field, Calif. He won the Nobel Prize for Physiology/ Medicine in 1976.
SAN FRANCISCO -- Astrobiology is the scientific study of how life interacts with the planets and other objects in our cosmos. Several fundamental questions drive this field. How did life arise? Are we alone in the universe? What is the future of life beyond our home planet? Implicit in this quest is the determination of a set of characteristics that distinguishes the living from the non-living, even though an absolute definition may not be now possible.
At a time when many scientific fields are becoming specialized and narrow, astrobiology is interdisciplinary. It includes astronomers, geologists, planetary scientists, paleontologists, biologists, physicists, chemists, philosophers and others interested in the implications of the existence or non-existence of life beyond Earth. The search for life elsewhere became much more accessible when NASA and other space agencies developed the launching capability, instruments, satellites and exploratory missions to our planetary neighbors that have exploded the knowledge of our universe.
We are all made of stardust. The lighter basic chemical elements of living matter derive from the Big Bang, and the heavier elements are generated in the radioactive interiors of stars that spread through space when the stars are destroyed. A dramatic recent development has been the discovery of more than 85 planets orbiting other suns. NASA and other agencies will, in the next few years, launch satellites that will find and study additional extra-solar planets, including those of about Earth size that could be habitable.
Pre-biotic chemistry is concerned with the complex processes that form organic chemicals from which the information-rich biological molecules and structures -- proteins, nucleic acids, cell walls, etc. -- that characterize life are assembled. Geologists seek the earliest forms of life in the oldest geology formations. Molecular and evolutionary biologists look for early antecedents to existing life. How does living matter affect geology and other natural forms? These and other investigations can identify ''biosignatures,'' that is, markers of present or previous life. These will be used in the search for life.
The major targets for the search for life in our solar system are Mars and Europa, the Galilean moon of Jupiter. Mars is the planet most similar to Earth; it lies closer to the ''habitable zone'' (the region in the solar system near where Earth orbits, and where life possibly could exist) than any of the other planets. Liquid water may have existed on the surface of Mars in the past, and it still exists in frozen form and possibly, in hidden places, as a liquid. Astrobiologists have helped to select sites for the Martian Landers that NASA and the European Space Agency will launch in 2003 and to develop instruments that can be used to detect biosignatures.
Liquid water is thought to be a prerequisite for life. Europa has an ice-covered surface with, probably, a vast liquid ocean containing more water than all the Earth's oceans hidden beneath it. Robotic missions to Europa and, in time, landings of instruments contained in autonomous submarines are being considered. Titan has an atmosphere rich in organic material and is of interest for the study of pre-biotic chemistry. It will be visited about three years from now when the Cassini mission undertakes further explorations of Saturn and Titan, including a parachuted lander to study organic molecules in Titan's atmosphere.
Early Earth was, by contemporary standards, a hostile environment. There was a period of heavy bombardment by meteorites and comets that disturbed any ecologies that may have existed and, in some cases, may have sterilized our planet. Oxygen was low, violent volcanic eruptions were frequent, there were periods of freezing cold, intense heat, ultraviolet radiation and dehydration. Hence, life may have existed in protected and/or extreme places; in geothermal vents on land and under the sea, deep under the Earth's surface, in the interstices of ice crystals, in water of high and low acidity, etc. There are locations on Earth now that mimic these extremes and can be considered as analogues of Mars or Europa as well as early Earth.
Astrobiologists have an adventurous life, not only by participating in space missions but on field trips on Earth. They may be found on oceanographic ships looking for bacteria and viruses deep under the sea floor, at geothermal sites on the mid-ocean ridges, at an ancient meteorite impact crater that blasted what is now Devon Island in the Canadian Arctic archipelago more than 20 million years ago, or at the site of Lake Vostock in a remote part of the eastern Antarctic. Vostock is a deep lake miles under glaciers and snow that is an analogue for the hypothesized Europan Ocean.
The study of space compels us to look at our home planet with different eyes. Once Europa has been observed and studied, we cannot look at earthly ice in the same way. When we observe how life has interacted with Mars, we recognize the beauty and richness of our planet and value its preservation and fate.
In the late 1990s there were several events that rekindled NASA's interest in astrobiology and related subjects. These included the discovery of extra-solar planets, increased knowledge of deep space derived from the NASA Hubble Space Telescope and the possibility that a meteorite from Mars discovered in the Antarctic -- ALH 84001 -- might contain evidence of very ancient extraterrestrial life (a matter still in dispute). Additional funding was found and some of this was dedicated, in 1997, to the NASA Astrobiology Institute (NAI). An Astrobiology Roadmap -- a broad synthesis of the dimensions of the field -- was created in 1998 at a meeting of several hundred academic and other scientists. Based on this Roadmap and the NASA mission, the scientific community applied for funding of basic interdisciplinary discovery research. Eleven Lead teams were selected by a non-governmental peer review group. They included universities, research institutes and NASA centers. (Four teams were added in 2001.) There are more than 700 members of the NAI, including 13 members of the prestigious U.S. National Academy of Sciences. NAI research is innovative; investigators are told that they are expected to change their plans as new findings generate new ideas.
In addition to scientific research a major part of our mission is to develop methods to manage and enhance a virtual organization. Our 15 teams are spread throughout the United States, and our international partners are worldwide. We are developing collaborative skills and electronic methods of communication to allow people at a distance to work together. This is a major issue in a world that is globalizing. We plan to pioneer these methods for the benefit of scientific and other organizations. In addition to the U.S. teams we have affiliations and associations with international teams -- Spain, the United Kingdom, France, the European Union, Australia -- with whom we collaborate on many of our projects.
Astrobiology is generational in character. For example, an NAI focus group is currently planning research on Europa. However, the mission will not be launched for several years and, at the current rate of space travel, it will take five years to arrive at its destination. Several such missions are planned. Although scientific research papers will be produced as the work proceeds, the scientists who are designing the missions will not be around to receive the data to test many of their hypotheses. This will be done by their, or someone else's, children and grandchildren. It is akin to the building of cathedrals that required, in some cases, hundreds of years.
Space science and astrobiology are future-driven endeavors of interest to all humankind. They deal with fundamental questions of universal concern. The questions approached by science are also the concern of philosophy, religion, literature and art. It is a grand mission with frequent exciting new discoveries that stirs and will continue to stir the imagination and enthusiasm of scientists and many others.
(c) 2002, Nobel Laureates. Distributed by Los Angeles Times Syndicate International, a division of Tribune Media Services.
For immediate release (Distributed 4/18/02)