2003 Elsevier Science Ltd. All rights reserved.DOI 10.1016/S0958-1669(03)00073-9AbbreviationsNAI NASA Astrobiology InstituteNASA National Aeronautics and Space AdministrationNSF National Science FoundationSETI search for extraterrestrial intelligenceIntroductionThis article introduces the multidisciplinary field of astrobiology,which bridges the gap between the biological andphysical sciences and engineering. In addition, recommendationsare made for astrobiology to serve as analternative model for teaching science and engineeringat all levels of education including primary, secondary,undergraduate and graduate students. I am writing thisarticle largely based upon the experience that my colleaguesand I have had in developing a PhD program inastrobiology at the University of Washington.What a difference a word makesFor four decades the National Aeronautics and SpaceAdministration (NASA) sponsored a science program onexobiology, a term which, by definition, refers to thestudy of life outside Earth. Excluding Earth and earthlingsseems inappropriate for at least three reasons. First, itis ironic to disregard Earth, because it is the only place sofar known in the Universe where life actually exists.Second, exobiology implies that there is something verydifferent and strange about creatures from other planetarybodies. Why shouldn’t all living matter in the Universeshare common properties in the same sense as othermatter? Third, the study of life on Earth, including itsevolution and diversity, provides valuable clues and lessonsfor the exploration of other worlds that may harborlife. After all, if we cannot understand life, its origins andits limits on Earth, how can we possibly begin to identifylife and efficiently study it elsewhere?The perception of scientists and lay people has changedsince NASA introduced the term astrobiology, becauseit optimistically embraces the study of all life in theUniverse, including life on Earth. The introduction ofthe term astrobiology coincided with NASA’s establishmentin 1998 of the NASA Astrobiology Institute (NAI),which now encompasses about a dozen universities andresearch centers at NASA and elsewhere (http://www.nai.arc.nasa、gov). In the five years since the NAI began asa virtual institute, an international effort has linked itsastrobiology program to those of several other countries.These include Spain (Centro de Astrobiologia), the UnitedKingdom (UK Astrobiology Forum and Network), France(Groupement de Recherche en Exobiologie), Europe(The European Exo/Astrobiology Network Association)and Australia (Australian Centre for Astrobiology).Why is astrobiology so appealing?How is it that astrobiology has captured the curiosity,fascination and admiration of so many? Surely much of itsappeal has to do with the great metaphysical questions ofastrobiology. Where did we come from? How does lifebegin and evolve? What is life’s future? Does life occurelsewhere in the universe?This young and vigorous field holds great expectationsthat these questions can and will be answered. Herein liesthe appeal of astrobiology. Not only is the subject matterof broad interest to virtually all of us, it is basic to ourperception of the world in which we live. Furthermore,scientists are sanguine about our ability to answer at leastsome of these questions in the foreseeable future. So, it isnot surprising that the air bristles with excitement and347www.current-opinion、com Current Opinion in Biotechnology 2003, 14:347–354anticipation at astrobiology meetings as scientists reporthow they are unraveling the mysteries of life, its tenacity,fragility, distribution and origins.The transcendent nature of astrobiologyAstrobiology is remarkable in its extreme breadth andtherefore its potential for multidisciplinary educationand research. It touches on virtually all fields of scienceand engineering. As a result it is perhaps unique among alldisciplines. Astrobiology is unlike, for instance, biologywhich is exclusively centred on the study of all aspects oflife on Earth. Astrobiology, by contrast, considers questionsthat transcend our planetary boundary. When biologistsask the question ‘What is life?’ they are constrainedby the range of life forms on Earth. However, when theastrobiologist asks the same question, all boundaries areremoved. The astrobiologist is no longer confined to lifeon Earth, but is forced to conjure possibilities beyond therequirements of water and the DNA! RNA! proteindogma. Indeed, imagination is the only limitation to theastrobiologist’s thinking, although it is a severe one. Totest your own imagination, contemplate the question‘What is life?’ and propose one or two truly alternativelife styles to that which we know so well.A special multidisciplinary challenge for astrobiologyrelates to the dating of early events on Earth and providesanother example of its transcendent nature. Geologistsworking with paleontologists provided us with theGeological Timetable during the last half of the 20thcentury. From this effort, much was learned about thepast 600 million years of animal and plant evolution.However, little is known about early evolution, that is,from the Precambrian Eon after Earth’s formation about4.5 billion years ago until 600 million years ago. Our onlyhope to uncover this information is through the mutualefforts of geologists, micropaleontologists, microbiologistsand phylogeneticists. Fossils alone cannot answerthe important questions about the order in which processessuch as methanogenesis and sulfate reductionoccurred, because microbial fossils are too simple. Chemicalbiomarkers for processes and specific microbialgroups are needed in conjunction with phylogeneticanalyses. Already astrobiologists from the various disciplinesare talking with one another about resolving thisissue through multidisciplinary efforts.So, not only does astrobiology provide genuine appeal toall, but it is perhaps unique in its transcendence ofscience. It encompasses aspects of biology, astronomy,physics, planetary sciences, chemistry and geology as wellas the social sciences. Example topic areas in astrobiologyare given in Box 1.Interdisciplinary astrobiology researchMuch of the exciting research in astrobiology lies at theinterface between two or more disciplines. For example,microorganisms are intimately involved in rock weatheringprocesses. From an astrobiological perspective,biological weathering processes leave ‘signatures of life’such as specific biological compounds or microbial fossilsthat could be used to identify life on rocks from otherplanetary bodies such asMars. The traditional training ofgeologists and microbiologists does not prepare PhDgraduates to study these geobiological activities by themselves;however, in astrobiology, scientists work togetherin designing and testing hypotheses and thereby expandingour understanding of fundamental but poorly studiedprocesses.In our astrobiology PhD program at the University ofWashington, we have seen examples of interdisciplinarywork that have resulted in unique perspectives. It isnoteworthy in this regard that it is not always the facultywho have made these breakthroughs, but it is often ourPhD students. One example of this is work carried out byan astronomy student, John Armstrong, and a biologystudent, Llyd Wells, who have worked with an astronomyfaculty member, Guillermo Gonzalez. They proposedthat the Moon, as ‘Earth’s attic’, probably containsrocks with microbial fossils and other signatures of lifefrom Earth that were ejected to the Moon as it driftedaway from Earth after its formation. These fossils wouldbe well preserved, because they have not been exposedto weathering and tectonic processes on Earth. Theserocks are therefore likely to contain geochemical andfossil evidence that may tell us much about early Earthhistory [1]. In a second paper, they suggest that, had amajor sterilizing impact occurred on Earth following theevolution of life, rocks subsequently ejected from theMoon by an impact event could have been brought backto Earth to re-seed it [2]. These papers are having amajor influence on NASA’s thinking concerning thepossibility of launching amission to theMoon to retrieveearly Earth rocks.Another example of interdisciplinary collaboration involvestwo of our faculty members. Peter Ward and DonBrownlee, a paleontologist and an astronomer, respectively,have collaborated in writing two recent provocativebooks on astrobiology, ‘Rare Earth’ and ‘The Life and Deathof Planet Earth’ (Box 2).Box 1 Example topic areas in astrobiology. Star birth, death and recycling of elements Formation of planetary systems Origin and evolution of life Search for extraterrestrial biosignatures Habitable planets and satellites within and beyond our solar system Earth’s early geosphere, hydrosphere and atmosphere Earth’s early biosphere Mass extinctions and diversity of life Fossil and geochemical evidence of early life Life in extreme environments Planetary protection348 Science policyCurrent Opinion in Biotechnology 2003, 14:347–354 www.current-opinion、comAstrobiology as an exciting new field forresearchIn this brief article, it is not possible to provide detailedinformation about ongoing astrobiology research that ischanging our views of our world and the possibility of lifeelsewhere. What I have done is to ask my colleagues tosubmit references of recent articles that they believehave made major contributions in their fields. I havegrouped these below under various astrobiology subjectheadings along with brief descriptions of their contentand significance. This is not meant to be a completelisting, but should provide an indication of the vitalityand breadth of the field. An excellent general referenceon astrobiology has been written by Des Marais andWalter [3].Extreme environments and extremophilesSeveral groups have looked at extreme environments onEarth, protracting their findings to possible conditions onother planetary bodies. For example, Doran and colleagues[4] report on Lake Vida, one of the largest lakes inthe McMurdo Dry Valleys of Antarctica, which was previouslybelieved to be frozen solid. However, it now turnsout to contain a briny liquid (seven times seawater salinity,temperature below 108C) beneath a 19 m thick icecover that has effectively isolated the brine for about 2800years. The ice cover contains microbial populations thatare metabolically active upon thawing. The physicalfeatures and geological history of the lake suggest itmay be an analog of the last vestige of an ancient Martianaquatic ecosystem.Similarly, Kelley and coworkers [5] describe a new classof marine hydrothermal system hosted on peridotites.The field hosts at least 30 active and inactive 30–60 mtall carbonate chimneys that vent fluids at 40–758C withpH values of 9–10. The chimneys harbor dense anddiverse microbial communities. Because this system ishosted in peridotites, it is very reducing and associatedwith high pH fluids. It may be the best current analogto hydrothermal systems that operated on early Earth(Figure 1).Other groups have investigated various environments,including winter sea-ice [6] (Figure 2), active sulfidechimneys [7,8], and the acidic, iron-rich red river, RioTinto, in Southern Spain [9]. Together, these types ofstudies have highlighted the harsh environments in whichlife can exist and have helped scientists understand therange of environments outside Earth that may harbormicrobial life.Geological sciencesSudbury in Ontario is the largest known and most importantbolide impact structure (astrobleme) on Earth, beingone of the first to be recognized and debated. Its manygeological features are exposed at the Earth’s surface, andBox 2 Astrobiology book and journal list (since 2000).TextbooksBennett J, Shostak S, Jakosky B: Life in the Universe. Boston:Addison Wesley; 2003.For introductory college courses for nonscience majors; strongeron the physical sciences than biologyGoldsmith D, Owen T: The Search for Life in the Universe, 3rd Edn.San Francisco: Benjamin Cummings; 2002.For introductory college courses for nonscience majors; strongeron the physical sciences than biologyPrather E, Offerdahl E, Slater T: Life in The Universe ActivitiesManual. Boston: Addison-Wesley; 2003.Student activities to accompany the textbook by Bennett et al.Zubay G: Origins of Life on the Earth and in the Cosmos, 2nd Edn.London: Harcourt; 2000.Tutorial approach to the biochemistry of how life works and its originPopular booksClark S: Life on Other Worlds and How to Find It. New York:Springer-Praxis: 2000.Darling D: Life Everywhere: the Maverick Science of Astrobiology.New York: Basic Books; 2001.Well-written; includes personalities of researchersDarling D: The Extraterrestrial Encyclopedia: an AlphabeticalReference to All Life in the Universe. Three Rivers; 2001.deDuve C: Life Evolving: Molecules, Mind, and Meaning. Oxford UK:Oxford University Press; 2002.Nobelist argues for the inevitability of the emergence of lifeDick S: Life on Other Worlds: the 20th Century Extraterrestrial LifeDebate. Cambridge UK: Cambridge University Press; 2001.Shorter, popular version of ‘The Biological Universe’ listed belowFry I: The Emergence of Life on Earth: a Historical and ScientificOverview. New Jersey: Rutgers University Press; 2000.Excellent overview of past and current ideas on the origin of lifeGrady M: Astrobiology. Washington: Smithsonian Institution Press; 2001.Nice slim volumeKoerner D, Levay S: Here be Dragons: the Scientific Quest forExtraterrestrial Life. Oxford UK: Oxford University Press; 2000.Ward P: Rivers in Time: the Search for Clues to Earth’s MassExtinctions. Columbia: Columbia University Press; 2000.Ward P, Brownlee D: Rare Earth: Why Complex Life is Uncommon inthe Universe. Copernicus, 2000.Pioneering synthesis; astronomer and paleontologist argue that planetswith conditions for life more complex than single cells arerare in the UniverseWard P, Brownlee D: The Life and Death of Planet Earth: How theNew Science of Astrobiology Charts the Ultimate Fate of OurWorld. New York: Henry Holt; 2003.Wills C, Bada J: The Spark of Life: Darwin and the Primeval Soup.Cambridge MA: Perseus; 2000.Scholarly publicationsDick S: The Biological Universe: the Twentieth-CenturyExtraterrestrial Life Debate and the Limits of Science.Cambridge UK: Cambridge University Press; 2000.The definitive historical study of the development over the 20thcentury of ideas (both scientific and more popular, e.g. UFOs) onextraterrestrial life, origin of life, exobiology and astrobiologyHorneck G, Baumstark-Khan C (Eds): Astrobiology: The Quest for theConditions of Life. New York: Springer; 2002.Most chapters (by separate authors) are an outgrowth of aworkshop on astrobiology held in Germany; uneven coverageLemarchand G, Meech K (Eds): Bioastronomy ‘99: A New Era inBioastronomy. Proceedings of the Astronomical Society of thePacific Conference; Hawaii, USA, 2–6 August 1999. Vol. 213.ASP, 2000.Proceedings of a wide-ranging conference; strongest on the astronomyJournalsAstrobiology. New York: Mary Ann Liebert, Inc.; (2001–).International Journal of Astrobiology. Cambridge UK: CambridgeUniversity Press; (2002–).Astrobiology, the transcendent science Staley 349www.current-opinion、com Current Opinion in Biotechnology 2003, 14:347–354it is one of the world’s largest sources of nickel ore. TheFe-Ni-Cu-S ore was not derived from the bolide, butformed by processes induced by the impact. Naldrett [10]has reviewed our current understanding of this site in anarticle that illustrates the contribution of the geologicalsciences to astrobiology.Planetary and atmospheric scienceAstronomers are beginning to discover planets beyondEarth’s solar system and new models are being proposedfor their formation [11]. Data from the Hubble SpaceTelescope provided the first direct detection of the atmosphericcomposition of a planet orbiting a star outside oursolar system [12]. Sodium was found in the atmosphereof a planet orbiting a yellow, Sun-like star called HD209458, located 150 light-years away in the constellationPegasus. Although this particular planet is a gas giant likeJupiter and unlikely to harbor life, the study demonstratedthat it is feasible to measure the chemical makeupof extrasolar planetary atmospheres and to potentiallysearch for the chemical markers of life (such as O2)beyond our solar system [13].Recent evidence strongly supports the view that Mars haswater that has flowed in the recent past, supporting thenotionthat subsurface brinesmayexist [14].Bolideimpactsin the past may have thawed frozen subsurface waterleading to temporary episodes of rain and flash floods [15].Earth may have actually frozen over completely in itspast, a phenomenon referred to as ‘Snowball Earth’.Hoffman and Schrag [16] have recently reviewed thisfield and Warren et al. [17] discuss where surface life mayhave survived during one of these remarkable events.Until recently, atmospheric scientists explained how earlyEarth could remain unfrozen even when the sun was 30%less luminous because they believed the atmosphere hadhigh levels of the greenhouse gas, carbon dioxide. Thisview has now changed as Pavlov et al. [18] showed howbiogenic methane in an early anoxic atmosphere couldhave served as the key greenhouse gas. Catling et al. [19]showed that the high methane concentration in the earlyatmosphere could also explain the oxidation of the atmosphere:ultraviolet light’s decomposition of methane tohydrogen and its escape to space would have left Earthmore oxidized before biogenic oxygen production.Early evolutionAs surprising as it may seem microbiologists are stilldiscovering on Earth entirely new kingdoms ofmicrobiallife including representatives from each of the threeFigure 1Several groups have looked at extreme environments on Earth, protracting their findings to possible conditions on other planetary bodies. Kelley andcoworkers [5] described a new class of marine hydrothermal system from the mid-Atlantic Ridge that is hosted on peridotites, which may be thebest current analog to hydrothermal systems that operated on early Earth. The figure shows a hydrothermal vent off the coast of Washington State.The structures at this site vent at temperatures up to 3008C. Detailed analyses of one of the sulfide structures shows that they host dense anddiverse microbial communities. (The photograph is reproduced with kind permission from D Kelley.)350 Science policyCurrent Opinion in Biotechnology 2003, 14:347–354 www.current-opinion、comdomains, the Bacteria, Archaea and Eucarya. One exampleis described in the recent paper of Huber et al. [20]who reported an unexpected group of the Archaea,known species of which parasitize other members ofthe Archaea.Much confusion still exists about the evolution of the firstorganisms. Woese [21] considers the importance of horizontalgene transfer on the evolution of early cellular life.He proposed the ‘Darwinian Threshold’ as a seminalperiod that separates early evolution in which horizontalgene transfer dominated evolutionary processes from thesubsequent period in which evolution followed the verticalinheritance of life as we now know it.Although evidence indicates that many of the traits of theEucarya can be traced to the Bacteria and Archaea, untilrecently tubulin genes have only been found in theEucarya, all species of which have them. However, thistoo is no longer true; a bacterium that contains a- andb-tubulin homologs has now been discovered [22].PaleontologyShen et al. [23] demonstrate the existence of microbialsulfate reduction as early as 3.45 billion years ago, providingthe first evidence of a specific metabolism inEarth’s evolutionary record. As this is typically a heterotrophicmetabolism in which organic matter is oxidizedanaerobically with sulfate, it implies that microbial ecosystemswere already quite diverse with complex trophicwebs and biogeochemical cycles. As sulfate reductionrequires sophisticated biochemical control, it furtherimplies that soon after the end of heavy meteorite bombardmentof the Earth, life was already quite advanced inits cellular functions.Considerable doubt has been cast on the claim that thereis carbon-isotopic evidence for life on Earth older than3.85 Ga [24,25]. If correct, this claim would imply thatautotrophic organisms inhabited the Earth at the time ofthe heavy meteorite bombardment and therefore that lifecould have been widespread in the early solar system. VanZuilen et al. [24] argue that the observed carbon-isotopefractionation is not biotic, but is instead the result ofmetamorphic carbonate reduction to graphite. Fedo andWhitehouse [25] argue that the host rock for this graphiteis an altered igneous rock and not a sedimentary bandediron formation, so it should not be expected to hostbiological remains.Planetary protection and the search forextraterrestrial intelligenceAstrobiologists are concerned about the biological contaminationof planetary bodies by life from elsewhere.Figure 2Sea-ice on Earth has become a model system in which to study planetary bodies such as Jupiter’s moon Europa, which has a frozen ocean that isshown in close-up view. The texture of the ocean supports the view that there are large blocks of ice floating on a liquid ocean that may supportmicrobial life. (Figure reproduced with courtesy of the Jet Propulsion Laboratory at NASA/Caltech.)Astrobiology, the transcendent science Staley 351www.current-opinion、com Current Opinion in Biotechnology 2003, 14:347–354Rummel [26] has written an accessible review of thehistory and state of planetary protection policy and implementation.More specific issues, such as the handling andquarantine of samples returned from elsewhere (e.g.Mars), have been considered in some detail [27].In part 1 of a comprehensive treatment of biologicaltransfer, Mileikowsky et al. [28] discuss the potentialfor the natural transfer of microbes between solar systembodies. This is based on knowledge that large impactevents (from comets or asteroids) occurring on one bodycan propel significant quantities of material off a planetarysurface and into solar orbits that may intersect the orbitsof other bodies.The search for extraterrestrial intelligence (SETI) continuesas one of the earliest endeavors that has attemptedto discover advanced life on other planetary bodies [29].NASA’s astrobiology website contains links to the NAIprojects as well as an Astrobiology Roadmap thatdescribes research goals. Perhaps what is most remarkableis that, during the past decade, this field has grown from asmall core of dedicated scientists to a large and impressivegroup with many young scientists. With the emergence ofnew technologies, such as genome sequencing and extrasolarsystem planetary discovery techniques, our understandingin all areas from molecular evolution to planetaryhabitability is rapidly transforming our comprehensionof astrobiology.Astrobiology’s promise for multidisciplinaryscience education and researchMost educators agree there is a need to rethink scienceand engineering education. Many of the traditional disciplinesseem to lack context in our modern world, at leastto many young scholars. By incorporating astrobiologyinto a curriculum, the treatment of subject matterchanges. For example, consider the biology instructorwho is interested in teaching about the diversity of life.A typical approach would be to discuss the differentspecies from each of the numerous animal groups andhow some are being threatened with extinction due tohabitat loss. In an astrobiology course the diversity issuecould be addressed in the context of mass extinctions,such as, ‘What happened to the dinosaurs?’ The answer tothis question entails a discussion of biology, paleontology,astronomy, physics (for dating fossils), evolution andcould be followed up by a discussion of the human-drivenmass extinction that is occurring now. Therefore, astrobiologycan provide a compelling way of integrating thesciences in the classroom.Also, from a pragmatic standpoint, the subject matter inastrobiology is very flexible. It can be taught within thestructure of an entire science curriculum at one extreme,or as a single course. Furthermore, astrobiology can betaught to all educational levels and it serves as an engagingoutreach program to the public.Because of the interest in astrobiology courses, severalbooks have recently been published, some of which couldserve as textbooks for courses at the undergraduate andgraduate levels (Box 2).Policy recommendations for astrobiologyscience education and researchPhD traineeship programsEvidence from our University of Washington NationalScience Foundation (NSF) Integrative Graduate Educationand Research Traineeship (IGERT) astrobiologyprogram (http://depts.washington、edu/astrobio/) indicatesthat astrobiology can serve as an excellent subject area forinterdisciplinary PhD education in science and engineering.Because astrobiology is such a broad and excitingfield of study in science, it should be promoted as acurriculum in science education and research at thedoctoral level.We recommend that NASA, NSF and other appropriatefederal agencies should provide support for the implementationof PhD traineeship programs in science andengineering education in astrobiology. This will developa unique group of scientists and engineers who will beable to effectively communicate and collaborate with oneanother. Furthermore, they will be able to subsequentlytrain university students in astrobiology and interdisciplinaryresearch.Astrobiology students who receive PhD degrees will beideal candidates for the instruction of courses for doctoralstudents interested in astrobiology. At this time there arevery few students. Even when more students graduate,however, it should be recognized that they will not havethe in-depth experience to supervise students in PhDcourses and research in areas outside their own disciplinaryexpertise, so a co-mentoring approach appears moreappropriate. Astrobiology students trained in our programcomplete all of the necessary requirements in their majordepartment and, in addition, complete the requirementsfor the astrobiology program. Therefore, they can competeeffectively for post-graduate opportunities withothers in their own area, but have the added experienceof working in a multidisciplinary training environment,which, we believe, makes them better prepared for theirfuture careers.Astrobiology PhD programs are likely to remain interdepartmentalfor the foreseeable future. Although theymay eventually be accepted as departmental programs,this seems premature now as it may actually detract fromthe true vision of a cross-disciplinary field. Nonetheless, iflife is discovered elsewhere in our solar system or inanother planetary system, it could certainly lead to a need352 Science policyCurrent Opinion in Biotechnology 2003, 14:347–354 www.current-opinion、comto train additional astrobiologists through universitydepartmental programs. In this sense, an astrobiologytraining program could serve as a forerunner for the cadreof scientists and engineers eventually needed.The current NSF IGERT program is an excellent modelto use for development of a joint NASA-NSF or otheragency program, because of the importance it places onintegrative student training and support for developmentof novel educational ideas.Undergraduate university levelAstrobiology is currently amenable for the instruction ofundergraduate students in single courses. Textbooks areavailable that may be used for that purpose if institutionshave faculty members who can teach in the varioussubject areas.Because astrobiology covers such a vast area, most instructorswill find it difficult to teach an entire course; however,it could be team-taught by faculty from biology and thephysical sciences. Ultimately, as PhD scientists and engineersare trained in astrobiology, they would becomeideal candidates to teach an entire course at the undergraduatelevel.Our recommendation for teaching astrobiology at theundergraduate level is to provide support for training ofexisting faculty at institutions that wish to develop astrobiologycourses or a curriculum. This could be handled bysupporting faculty study leaves to a university in which agraduate level program in astrobiology is in place, as wellas at the various non-academic NAI institutions.Primary and secondary educationAstrobiology is an exciting field that is ideal for teachingscience to students in secondary education. Some materialsare currently available for this such as Astro-Venturefor grades 5–8, at the NAI site mentioned previously, andthe SETI Institute high school curriculum (www.seti、org/Welcome.html). However, there is a need to train teachersand develop additional instructional materials. Thiscould be initiated with a trial period at primary andsecondary schools that wish to pursue this subject matterin their science curriculum. Once this trial period is over,say after five years, the concept could be evaluated and, ifappropriate, implemented.To teach astrobiology at this level we recommend thatsupport is provided for workshops and course planningsessions for scientists from universities with astrobiologyprograms and science teachers of primary and secondaryschool students. The goal of these workshops is todevelop trial curricula for teaching astrobiology at theprimary and secondary levels. It would also be necessaryto support the development of astrobiology courses andappropriate educational materials (textbooks, videos,websites, etc) that could be used for teaching primary,secondary and undergraduate students interested inscience and engineering.ConclusionsRecent advances in scientific knowledge from such disparateareas as microbiology, astronomy, geochemistry,paleontology, genomics, planetary science and molecularevolution have culminated in the formation of the newfield of astrobiology. Astrobiology, which transcends virtuallyall of the sciences, aims to answer the great questionsabout the origin of life and its distribution andevolution in the Universe. Astrobiology has quicklyascended to international prominence as a novel multidisciplinaryand integrated scientific research area.Because of its innately interesting subject material, astrobiologyis ideally suited for teaching science from kindergartento the graduate level. Now is the time toimplement astrobiology into educational programs inthe form of new courses and new curricula. In order toaccomplish this goal, governmental resources will beneeded to train teachers and develop appropriate instructionalguidelines and materials.AcknowledgementsI want to thank my colleagues at the University of Washington who havemade suggestions and provided some of the references mentioned,especially Roger Buick, David Catling, Eric Cheney, Jody Deming,Deborah Kelley, Marsha Landolt, Thomas Quinn, Steve Warren and LlydWells. In addition, I wish to thank David Morrison who provided the booklisting and Woodruff Sullivan III who provided book annotations. Alsothanks to Rosalind Grymes and John Rummel for their excellentsuggestions, most of which I have adopted. I am also grateful to the NSFIGERT and NASA NAI programs for providing support for my laboratory’sresearch in astrobiology.References and recommended readingPapers of particular interest, published within the annual period ofreview, have been highlighted as: of special interest of outstanding interest1.Armstrong J, Wells L, Gonzalez G: Rummaging through Earth’sattic for remains of ancient life. Icarus 2002, 160:183-196.This paper suggests that the moon may contain fossils of early Earthorganisms in rocks that were ejected to the moon by impacts.2.Wells L, Armstrong J, Gonzalez G: Reseeding Earth by impacts ofreturning ejecta during the late heavy bombardment. Icarus: inpress.Since the moon probably received ejecta from early Earth, returningejecta from the moon could have re-inoculated the Earth, which mighthave been sterilized by large impacts.3.Des Marais D, Walter M: Astrobiology: exploring the origins,evolution, and distribution of life in the Universe. Annu Rev EcolSystems 1999, 30:397-420.Comprehensive review article with 100 citations of technical articles.4. Doran P, Fritsen C, McKay C, Priscu J, Adams E: Formation andcharacter of an ancient 19-m ice cover and underlying trappedbrine in an ‘ice-sealed’ east Antarctic lake. Proc Natl Acad SciUSA 2003, 100:26-31.5.Kelley D, Karson I, Blackman D, Fruh-Green D, Gee J, Butterfield D,Lilley M, Olson E, Schrenk M, Roe K: An off-axis hydrothermalfield discovered near the Mid-Atlantic Ridge at 308N.Nature 2001, 412:145-149.This paper announces the discovery and describes the nature of the novel‘Lost City’ hydrothermal vent system near the mid-Atlantic ridge.Astrobiology, the transcendent science Staley 353www.current-opinion、com Current Opinion in Biotechnology 2003, 14:347–3546.Krembs C, Deming J, Junge K, Eicken H: High concentrations ofexopolymeric substances in wintertime sea ice: implicationsfor the polar ocean carbon cycle and cryoprotection ofdiatoms. Deep-Sea Res 2002, 49:2163-2181.This study of winter sea-ice cores shows that the ice is filled throughoutwith high concentrations of exopolymeric substances (EPS). At winter-icetemperatures to as low as –208C, EPS were observed to protect organismswithin the ice against physical damage by encroaching ice crystals.7. Schrenk M, Kelley D, Delaney J, Baross J: Incidence and diversityof microorganisms within the walls of an active deep-seasulfide chimney. Appl Environ Microbiol: in press.A comprehensive, up-to-date treatment of the diversity of life withinactive sulfide chimneys. Fluorescence in situ hybridisation, 16S rDNAsequences and cell count data are provided in several transects/zonesacross the wall of a 3008C chimney from the Mothra Hydrothermal Field.8.Kelley D, Baross J, Delaney J: Volcanoes, fluids, and life insubmarine environments. Annu Rev Earth Planetary Sci 2002,30:385-491.This major review paper looks at processes in the mantle to the hydrospherein the context of impacts on microbial communities. Much of theinformation is directly relevant to astrobiological questions concerningthe flux of volatiles, heat sources and linkages to microbial processes.This paper is being used by numerous upper undergraduate and graduateclasses in a textbook fashion.9. Zettler L, Gomez F, Zettler E, Keenan B, Amils R, Sogin M:Eukaryotic diversity in Spain’s river of fire. Nature 2002, 417:137.DNA extracted from the acidic, iron-rich red river, Rio Tinto, in SouthernSpain showed that 60% of its biomass is contributed by eukaryoticmicroorganisms. 18S rDNA sequencing indicated this extreme environmentcontains a surprising diversity of eukaryotic microorganisms.10. Naldrett A: Presidential address: from impact to riches:evolution of geological understanding as seen at Sudbury,Canada. GSA Today 2003, 13:4-9.11.Mayer L, Quinn T, Wadsley J, Stadel J: Formation of giant planetsby fragmentation of protoplanetary disks. Science 2002,298:1756-1759.This planet formation article is causing a paradigm shift in the way wethink of planet formation and has implications for the ubiquity of planetarysystems.12.Charbonneau D, Brown T, Noyes R, Gilliland R: Detection of anextrasolar planet atmosphere. Astrophys J 2002, 568:377.This is the first report of an atmosphere of an extra-solar system planet.13. Des Marais D, Harwit M, Jucks K, Kasting J, Lin D, Lunine J,Schneider J, Seager S, Traub W, Woolf N: Remote sensing ofplanetary properties and biosignatures on extrasolar terrestrialplanets. Astrobiology 2002, 2:153-181.14. Malin M, Edgett K: Evidence for recent ground water seepageand surface runoff on Mars. Science 2000, 288:2330-2335.15. Segura T, Toon O, Colaprete A, Zahnle K: Environmental effectsof large impacts on Mars. Science 2002, 298:1977-1980.

概述

英文介绍

概述

太空生物学（Astrobiology,Exobiology）是研究生物和外空间物体的相互作用的科学。是研究关于地球以及整个宇宙的生命的起源、进化、分布和未来的科学。其中要回答的最基本的问题就是：生命是怎样起源的？空间生命的未来会怎样？我们是宇宙中的唯一生命体吗？太空生物学是一个新兴而迅速发展的领域，吸引了大量的政府基金和优秀的科学家。2003年10月15日我国“神舟”五号载人飞船成功发射以及随后的安全着陆，标志着中国在攀登世界科技高峰中，迈出了有重大历史意义的一步。中华民族在航天事业上的发展必将翻开新的篇章。

英文介绍

Astrobiology, the transcendent science: the promise of

astrobiology as an integrative approach for science

and engineering education and research

James T Staley

Astrobiology is rapidly gaining the worldwide attention of

scientists, engineers and the public. Astrobiology’s captivation is

due to its inherently interesting focus on life, its origins and

distribution in the Universe. Because of its remarkable breadth as

a scientific field, astrobiology touches on virtually all disciplines in

the physical, biological and social sciences as well as

engineering. The multidisciplinary nature and the appeal of its

subject matter make astrobiology ideal for integrating the

teaching of science at all levels in educational curricula. The

rationale for implementing novel educational programs in

astrobiology is presented along with specific research and

educational policy recommendations.

Addresses

Department of Microbiology, NSF Astrobiology IGERT Program,

University of Washington, Box 357242, Seattle, WA 98195, USA

Current Opinion in Biotechnology 2003, 14:347–354

This review comes from a themed issue on

Science policy

Edited by Rita R Colwell

0958-1669/03/$ – see front matter