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Transcript of [Mary Firestone] SETI Scientist(BookFi.org)
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SETI Scientist
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Animal Therapist
Astrobiologist
Computer Game Developer
Pyrotechnician
SETI Scientist
Virus Hunter
Volcanologist
WEIRD CAREERS IN SCIENCE
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Mary Firestone
SETI Scientist
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CHELSEA HOUSE PUBLISHERS
VP, NEW PRODUCT DEVELOPMENT Sally CheneyDIRECTOR OF PRODUCTION Kim ShinnersCREATIVE MANAGER Takeshi TakahashiMANUFACTURING MANAGER Diann GrasseSERIES DESIGNER Takeshi TakahashiCOVER DESIGNER Takeshi Takahashi
STAFF FOR SETI SCIENTIST
PROJECT MANAGEMENT Ladybug Editorial and DesignDEVELOPMENT EDITOR Tara KoellhofferLAYOUT Gary Koellhoffer
2006 by Chelsea House Publishers,a subsidiary of Haights Cross Communications. All rights reserved. Printed and bound in the United States of America.
www.chelseahouse.com
First Printing
9 8 7 6 5 4 3 2 1
Library of Congress Cataloging-in-Publication Data
Firestone, Mary.SETI scientists / Mary Firestone.
p. cm. (Weird careers in science)Includes bibliographical references and index.ISBN 0-7910-8701-8
1. Life on other planetsStudy and teachingJuvenile literature. 2.Interstellar communicationJuvenile literature. 3. Radio astronomyResearchUnited States. I. Title. II. Series.
QB54.F45 2005576.839dc22
2005012076
All links and web addresses were checked and verified to be correct at the time of publi-cation. Because of the dynamic nature of the web, some addresses and links may havechanged since publication and may no longer be valid.
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Introduction
What Is a SETI Scientist?
History of SETI Science
What Do SETI Scientists Do?
Astronomical Tools
Where Do SETI Scientists Work?
Profiles of SETI Scientists
Do You Want a Career in SETI Science?
Appendix
Glossary
Bibliography
Further Reading
Index
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TABLE OF CONTENTS
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AN UNUSUAL SIGNAL
IT WAS AUGUST 15, 1977, and a typical night at Ohio StateUniversitys Big Ear telescope. SETI (search for extraterres-trial intelligence) volunteer Jerry Ehman was going over BigEars computer printouts, as he always did, when he cameacross a strange signal. There, on paper, was evidence of aradio signal 30 times stronger than the usual noise from outerspace. The night would not be so typical, after all. Dr. Ehmantore the paper from the printer and wrote Wow! next to thesignal. He showed it to other scientists the next day. That week,the Big Ear telescope was turned in the direction of the strong
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Introduction
1Chapter
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signal, and kept that way for a full month. Everyonewaited, hoping the signal would repeat itself.
It did not. If it had, it might have been evidence of extra-terrestrials (ETs) trying to make contact with Earth. TheAugust 15, 1977, signal, known today as the Wow signal,remains famous in the field of SETI research. We stilldont know what it was, and we probably never will,Ehman says. The mysterious Wow signal was one of thestrongest ever received from outer space. But it was alsoone of several strong signals received by telescopes overthe years. According to scientists, none of these signals wasa sign of life in outer space. For a signal to be considered agenuine sign from ETs, scientists believe it must occurmore than once. So far, no repeat signals have arrived.
SETI scientists today are still seeking the real thing, butin the meantime, they devote their days to studying otherwonders of the universe.
SEARCHING THE STARS Have you ever looked up at the night sky and wondered ifthere was life out there beyond Earth? SETI scientists havea passionate curiosity about life on other planets (Figure1.1). Are we alone in the universe? How did life begin onEarth? How many planets revolve around stars? Do any ofthese planets support life? These questions, in addition toseeking contact with actual ETs, are what SETI scientistsare always thinking about.
WHY LOOK FOR ETI?Interest in extraterrestrial intelligence (ETI) is almost asold as civilization. Greek philosopher Democritus (b. 460B.C.) was among the first to declare his belief in inhabited
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9Introduction
Figure 1.1 This is an artists depiction of our solar system.
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worlds other than our own. Just about everyone has pon-dered the topic, at least at some point.
Today, SETI science benefits from advances in technol-ogy. Scientists search for extraterrestrial life because pow-erful telescopes, computers, and spacecraft that travelbetween planets have proven that other solar systems andplanets really do exist (Figure 1.2). They have anothergood reason to believe there might be life elsewhere in ourgalaxy. Actually, make that 400 billion reasons, sincethats how many stars are in the Milky Way. If a star of theright size and age is the right distance from a planet, thechance for life on that planet is a very real possibility.Why? Because our sun is a star, and we know that Earthsprecise distance from it is a foundation for the develop-ment of life.
10 SETI Scientist
What is Space Weather?
Scientists have discovered that weather occurs inspace. The sun is responsible for disturbances in ourspace environment, because it gives off a stream ofplasma called solar wind. It also periodically expels bil-lions of tons of matter. When directed toward Earth,these huge clouds of material can cause large magneticstorms in the magnetosphere and the upper atmosphere.
According to the National Aeronautics and SpaceAdministration (NASA), magnetic storms produce manynoticeable effects on and near Earth, such as the auroraborealis (northern lights) and aurora australis (southernlights), communication disruptions, radiation hazards toorbiting astronauts and spacecraft, surges in currentthrough power lines, and corrosion in oil pipelines.
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DISCOVERING OTHER PLANETSScientists have now discovered more than 100 planets out-side our solar system. There is clearly much more to know.In fact, new planets and stars are forming right now. SETIhas searched only one-billionth of the galaxy so far.
11Introduction
Figure 1.2 The Hubble Space Telescope records images of galaxiesin deep space.
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Other discoveries within our own solar system, such asthe fact that water that once flowed on the surface of Marsand the possibility that there was an ocean beneath the iceof Jupiters moon Europa, have caused a lot of excitementabout extraterrestrial life, even if its just microorganismsand ancient fossils. The discovery of a magnetospherearound Jupiters moon Ganymede and an ionosphere aroundIo have surprised scientists, since these are usually onlyfound around planets, not moons. What do these discoveriesmean? Might Jupiters moons Ganymede and Io have oncebeen covered with oceans, lakes, and grass? SETI scientistsare doing everything they can to find out.
Scientists look for extraterrestrial life because they wantto understand the universe. They begin by deepening theirunderstanding of Earth, and how life formed here. Discov-eries on Earth, such as the existence of life-forms in deepocean areas, where there is no light or warmth, have ledexperts to believe that life can exist in some uncomfortableplaces, including outer space. They cant help but wonderwhat the potential is for life to exist elsewhere. Life onEarth is about 3.8 billion years old, and despite someintense periods of extreme temperatures and asteroid bom-bardments, it has continued to thrive.
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A SETI (PRONOUNCED SEH-TEE) scientist searches for life inthe universe, especially on planets other than Earth. Extrater-restrial means beyond Earth. A SETI scientist may be anastronomer, an astrophysicist, or a biochemist. SETI scientistsuse advanced technology, such as telescopes and satellitedishes that receive flashes of light or radio waves from outerspace. They collect and analyze this information, looking forstrong, repeated pulses of energy from way out there.
WHAT ARE SETI SCIENTISTS LOOKING FOR?If you close your eyes, and think of extraterrestrial life, what
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What Is a SETIScientist?
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comes to mind (Figure 2.1)? You probably dont imaginebits of bacteria and ice. But these things are very impor-tant to SETI science. SETI science looks for intelligent lifein outer space, but it is also a branch of astrobiology.
Astrobiology studies extrasolar water, ice, rocks, plants,bacteria, and microorganisms to detect life-forms. Its true
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Figure 2.1 For many people, the first thing that comes tomind when they hear the term extraterrestrial is the lovablecreature from Steven Spielbergs film, E.T.
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that SETI is trying to make contact with technologicallyadvanced types of life that can talk back, read, and send sig-nals around the universe. But SETI is also very involved inlooking for signs of life (such as bacteria and ice) anywherein the universe, no matter how smart that life might be. Evenso, SETI sciences greatest dream is for another technicallyadvanced world somewhere in outer space to contact Earth.
WAYS OF LOOKINGMost SETI searches are conducted in our own galaxy, theMilky Way, which has 100 billion (100,000,000,000) stars.Powerful optical and radio telescopes scan the skies withtwo different search strategies: a Full Sky Survey searchthat looks at the whole sky, or a Targeted Search, whichfocuses on a particular section of sky, or a starwhateverthe scientist chooses. There is ongoing debate among SETIscientists about which is the best way to receive signalsfrom life in outer space.
Radio telescopes are the more effective tool, according tomost scientists, because radio waves can pass through thicklayers of interstellar gases and clouds, while the visiblelight waves of optical SETI cannot.
Scientists estimate that less than 1% of the sun-like starsin our region of the galaxy have Earth-sized planets in theirorbit. In August 2004, NASA reported that astronomersfound a new class of planets beyond our solar system.These . . . Neptune-sized planetsabout 10 to 20 timesthe size of Earthare far smaller than any of the previouslydetected extrasolar gas giants [gas-giant planets]. Its evenpossible that the new class of planets is rocky, like Earthand Mars, NASAs Website says.
Scientists have determined that the newly discovered
15What Is a SETI Scientist?
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planets are smaller than Jupiter, and think they might bemade of rock, or rock and ice, rather than gas, but add thatthey arent sure what theyre made of at this point.
WHAT HAPPENS IF WE HEAR FROM ETS?The surprise of contact from an ET would capture world-wide interest, so SETI scientists are extremely cautious aboutsignals. If telescopes actually do receive a signal that might befrom ETs, they are programmed to immediately confirm theirfindings by double-checking the signal. SETI uses radio tele-scopes with tens of millions of channels, and the worldslargest antennas, so signals of all kinds are very frequent.
If an unusual, artificial (not produced by planets or othernatural objects) signal is detected in the narrow bandwidthrange, then scientists will contact a second radio telescopeelsewhere in the world, to see if it has detected the signal,too. If the artificial signal is genuine, then an announce-ment would be made, worldwide.
World space organizations have come to an agreementabout what should be done in case of contact from alienbeings. The agreement is called the Declaration of Princi-ples Concerning Activities Following Detection ofExtraterrestrial Intelligence. There would be no secrecy. A
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Check It Out
You dont have to be a scientist to listen to the uni-verse. Tune your television to a channel that has nostation on it and observe the snow and listen to thescratchy sounds. Some of this is cosmic microwavebackground noise, being detected by your televisionsantennas. Scientists believe this static is the cooled-off part of the very hot Big Bang.
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portion of it reads: A confirmed detection of extraterres-trial intelligence should be disseminated promptly, openly,and widely through scientific channels and public media,observing the procedures in this declaration. The discov-erer should have the privilege of making the first publicannouncement.
SETI scientists using radio telescopes will know whentheyve picked up a signal, because they believe it will occuronly in the narrow band width of the electromagnetic spec-trum (Figure 2.2), at 300 Hz. There are many satellites inEarths orbit (for telecommunications and military surveil-lance) that produce such signals, so scientists continuouslyhave to sort out these unwanted signals. Any repeated,strong signal would stand out easily in this range.
17What Is a SETI Scientist?
Figure 2.2 This diagram shows the wide range of the electromagneticspectrum, demonstrating the size of wavelengths produced at differ-ent frequencies.
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A LOT CAN HAPPEN when a couple of physicists kick backand think out loud about the universe.
In 1959, Cornell University physicists Giuseppi Cocconi andPhillip Morrison had been doing just that. After chatting a lotabout gamma rays and how these rays could travel betweenstars, their discussion expanded into how the entire electromag-netic spectrum, including radio waves and microwaves, couldtravel at the speed of light through the universe (Figure 3.1).They wondered what would happen if scientists searched thesesignals for something unusual, or changed the focus of a tele-scope, just to see what they would find. Cocconi and Morrison
History of SETI Science
3Chapter
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then wrote a two-page paper called Searching for Inter-stellar Communications for the September 1959 issue ofNature, a British science journal, and waited to see howscientists in their field would respond. Other scientistsaround the world found no problems with their theories.
EXPERIMENTS WITH RADIO TELESCOPESAround the same time, other scientists began to experimentwith radio telescopes. One of these scientists was a youngradio astronomer named Frank Drake, whose studies werefueled heavily by his fascination with searching for aliencivilizations. His calculations told him that if a strong sig-nal were sent from Earth, with Earth technology, it could bedetected by a world 10 light years away from us, if thatworld had an 85-foot (26-meter) dish. The reverse, then,
19History of SETI Science
Figure 3.1 SETI science officially began after two Cornell scientistspondered what might happen if people studied radio signals forunusual activity from other places in the universe, such as theAndromeda galaxy (seen here).
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would also be true: We could hear signals from 10 lightyears away with an 85-foot dish.
In 1960, Frank Drake got the chance to try out his theo-ries. He developed a project, called Project Ozma, whichwas the first microwave radio search for artificial signalsfrom space. Using the 85-foot radio telescope at theNational Radio Astronomy Observatory in Green Bank,West Virginia, he set his sights on two of the nearest sun-like stars, called Epsilon Eridani and Tau Ceti. Sun-likestars, it was hoped, would also have planets in their orbit,just as the planets in our own solar system orbit the sun.These planets might have also produced life.
Drake thought his steady, single focus would bring someinformation. The telescope was tuned to these stars for sixhours each day, for nearly a year, but nothing happened.Still, Frank Drakes experiment got other scientists think-ing, especially the Russians, who invested huge sums ofgovernment money in new radio telescopes and research,although their experiments brought no significant results.
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Radio Telescopes
Radio telescopes are used for radio astronomy, plane-tary radar, and terrestrial aeronomy. Radio tele-scopes can detect signals transmitted from the Pioneer 10spacecraft, which was launched from Earth in 1972, nowmore than 6 billion miles (9.7 billion km) away. Its signalhas only the power of a flashlight, but it can still bedetected. It takes the signal more than 10 hours to reachEarth at the speed of light. According to ChristopherChyba at the SETI Institute, Pioneer 10 has itself becomean extraterrestrial source, it provides an excellent testfor our systemit comes in loud and clear.
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MEETING OF THE MINDSIn 1960, a group of distinguished scientists met in secret inGreen Bank, West Virginia, home of the National RadioAstronomy Observatory, to discuss establishing contactwith other worlds. The meeting was important to the fieldof SETI, because it was the first time communication withalien civilizations was seriously considered by the worldsmost prominent scientists, officially. The meeting was heldsecretly because the scientists who took part worried thattheir interest in ETs would make them objects of ridicule inthe scientific community.
Carl Sagan, a famous astronomer, was there. He said,these good scientists [were] all saying that it wasnt non-sense to think about the subject. . . . it was like this 180degree flip of this dark secret, this embarrassment. It sud-denly became respectable.
Rocket science and the space age was peaking aroundthis time. Astronauts were circling the Earth in space cap-sules and walking on the moon. It was a time when scien-tists had begun to wonder just how far their skills couldtake them, and whether they might actually be able to findlife on other planets.
PROJECT CYCLOPSIn the early 1970s, NASA hired a team of experts toresearch and analyze SETI science and technology. Theycalled it Project Cyclops. It became the foundation for fur-ther research and established SETI as a genuine scientificfield. Through NASA-supported studies and workshops,two main search strategies emerged: the Targeted Searchand the Full Sky Survey (see Chapter 2). NASA decidedto use both strategies in its overall SETI plan. NASA
21History of SETI Science
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named these searches High Resolution Microwave Survey(HRMS).
VOYAGERIn 1977, Voyager spacecrafts carried information aboutEarth, in case ETs came in contact with them. NASAexperts and scientists, government officials, business exec-utives, science educators, and many others produced a gold-covered, copper record that contained photographs, music,greetings in 62 languages, and sounds from the planet Earth.One copy of the record (plus a cartridge, stylus, and picto-rial instructions for playing it) was sent into space on eachof the Voyager spacecrafts. Carl Sagan said the most diffi-cult part of making the record was selecting just the rightmaterial to help others learn what life on Earth is like. Typ-ical questions for the group may have been: Which photos,songs, or sounds best represent the diversity of life onEarth? How would you identify universal themes so theycan be understood by alien life-forms?
THE MICROWAVE OBSERVING PROGRAMIn the late 1970s, NASA gave Ames Research Center thetask of examining 1,000 nearby sun-like stars in its TargetedSearch. At the Jet Propulsion Laboratory (JPL), scientistswould sweep all directions in the Full Sky Survey. NASAcalled the project the Microwave Observing Program. In1988, NASA headquarters formally adopted these strate-gies, and gave them more funds for continued searching.Four years later, the observations began (again), but in 1993,Congress suddenly voted to end the flow of money fromNASA to SETI. Senator Richard Bryan of Nevada con-vinced the government that spending tax dollars on SETI
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was wrong. He called SETI the Great Martian Chase. Thecancellation of funds was a major blow to SETI.
Without NASA money and support, scientists began tolose hope. They saw their dreams of finding ETI in theirlifetime going down the drain. Money is critical toresearch.
NASA had devoted $60 million and 23 years to the studyof SETI when it was forced to stop its involvement. But itsinvestment was not entirely wasted. NASA-supportedresearch had led to new technologies, which SETI woulduse on future projects. Also, NASAs long involvement inSETI had elevated the scientific quality of its research,which had previously been done largely by amateurs.
PRIVATE ORGANIZATIONSHowever, SETI science was never entirely dependent onNASA for its survival. The SETI Institute and the PlanetarySociety, both private organizations, stepped in to preservethe ongoing scientific search for ETI, in 1993. SETI Insti-tute took on the Targeted Search, and became its sponsor.
In 1995, SETI launched Project Phoenix, using the Tar-geted Search technology. For the Targeted Search, scien-tists at the SETI Institute compiled a list of 1,000 stars, andsearched for signals in the 1,0003,000 MHz range.
The Planetary Society, founded in 1980, had always hadan interest in the Full Sky Survey approach to searching forETI. Bruce Murray, chairman of the board for the PlanetarySociety, always believed SETI should not limit its search toparticular areas, but should search with a variety of tech-niques in all areas of the sky. The Full Sky Survey projectwas suitable for this way of doing things.
In 1995, with funds from the Planetary Society, Paul
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Horowitz of Harvard University launched Project BETA,a Full Sky Survey project. BETA (Billion-channel Extra-Terrestrial Assay) is based at the Harvard-SmithsonianObservatory in Cambridge, Massachusetts.
Around 1998, optical SETI was beginning to gain newinterest in the SETI community. New technology wasmaking it possible to accurately detect pulses of light fromlight years away. The University of California at Berkeleyand Harvard launched several optical SETI projects, bothTargeted Searches and Full Sky Surveys.
24 SETI Scientist
You Can Discover a New Planet
PlanetQuests Collaboratory can turn your computer intoan astronomical observatory and resource library if youdownload the free Collaboratory software, available onthe PlanetQuest Website. PlanetQuest telescopes arefocused on extremely dense star regions, such as the cen-ter of the galaxy in Sagittarius, and when an observingrun ends and thousands of images have been collected,data is downloaded to your home computer, your Col-laboratory software will begin to analyze it.
In less than a month, the PlanetQuest Website says,you should know whether you have a planet candidate.But even if you dont yet, you will have discovered impor-tant new information about that starinformation thatwill contribute to our overall understanding of the uni-verse. With our telescopes and your computer, youllmake real discoveries at the frontiers of knowledge.
Most exciting of all, one writer for PlanetQuest says,you could discover a new planeta never-before-seenworld beyond our solar system! You will be credited foryour discovery, and your find will be entered into thePlanetQuest catalog.
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Optical SETI is continuing to gain momentum. In 2001,scientists at the University of Californias Lick Observa-tory, the SETI Institute, and the University of California atBerkeley joined together to support a project using a newpulse-detection system, which can find laser beacons fromcivilizations many light years away from Earth.
PROJECT SERENDIP AND SETI@HOMEProject SERENDIP, which began in 1979, has greatlyexpanded. In 2005, SERENDIP IV is operating at theArecibo Observatory in Puerto Rico. This is a radio astron-omy project, with equipment piggybacked onto Arecibosgiant dish. This allows SERENDIP to run continuously.
SETI@home began in 1999, as part of ProjectSERENDIP. SETI@home is a unique project that usesscreensavers on the personal computers (PCs) of volunteersaround the nation, to process SERENDIPs data. PC usersthen send the data back to the laboratory for more number-crunching. Without the help of these volunteers, the datawould take much longer to process.
25History of SETI Science
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BESIDES TRAVELING TO EXOTIC telescope sites around theworld, making television and radio appearances, and writingarticles about their work, SETI scientists type reports, answere-mail, write grants, and surf the Internet for new information.
Depending on their skills, SETI scientists may also performadministrative duties. They may become research team leaders,program managers, or planetarium directors. They can be sci-ence journalists or editors of scientific journals. If they are pro-fessors, they teach college classes, plan lectures, writescientific papers, and supervise student projects.
What Do SETIScientists Do?
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When SETI scientists work in laboratories, they analyzedata from research and telescope searches, write down theirconclusions and observations, and sometimes even developnew scientific theories and laws.
Most scientists in SETI work in collaboration with othersto conduct studies or to design and develop new procedures.Teamwork is a common approach to large-scale projects.
MATH RULESMath is a big part of SETI science. SETI astronomers andastrophysicists develop mathematical tables to get a betterunderstanding of the positions of the sun, moon, and stars,and to analyze the wavelengths of their radiation. Theycalculate orbits and determine the size, shape, brightness,and motion of different celestial bodies.
They use their extensive training in math, physics, andastronomy to think about stars, planets, moons, solar sys-tems, and galaxies (such as our own, the Milky Waygalaxy). They also study the galaxies chemical makeup,and the effects of those compositions on planetary atmos-pheres and biology. SETI scientists sometimes workclosely with computer programmers, designing sensitiveequipment for listening to the stars. SETI scientiststhink of radio telescopes as ears that listen, since theydetect what we cannot see with our eyes.
No matter what job they have, SETI scientists spend a lotof time at their computers. They use computer software tocalculate planetary orbits, to determine the size and shapeof stars, and to find out their brightness and movements.They process their calculations by typing in numbers andletters. They use critical thinking and problem-solvingskills on a regular basis.
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SETI scientists analyze wavelengths of radiation fromcelestial bodies in our solar system and beyond, and makenotes of their findings. SETI scientists often consult withother scientists and experts. They are often consulted by themedia to report on new SETI projects, and they make pub-lic speeches about the field of SETI science. They alsotravel around the world to attend workshops with other sci-entists, engineers, and technologists.
AREAS OF RESEARCHSETI scientists receive education and skills that are indemand. Technology is a big industry, and space technologyis an expanding field, both scientifically and commercially.
SETI scientists may also work as astrobiologists, physi-cists, electrical engineers, or chemists. As lead investiga-tors, researchers, or technology experts, SETI scientistsmay work in government jobs, institutes, and universities,studying one or more of the following topics:
interstellar organic chemistry
the formation of planets
extrasolar planets
lifes origins
life in extreme environments
planetary climatology
Mars
how asteroids and comets have affected life on Earth.
TARGET MISSIONS AND FOCUS GROUPSThe universe is bigger than we can imagine, so scientistspick certain parts of it, trying to understand it just a little at
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a time. At NASA and the Ames Research Center (ARC),SETI scientists frequently work in focus groups, and mis-sions where they use a new instrument, technology, orapproach and apply it to new or existing facts about life inouter space. Focus groups and missions consist of teams ofscientists, which are formed to focus their studies on aparticular area of space research. Some projects currentlyunder way include the following:
Mars Focus GroupThe Mars Focus Group considers past or present Martianlife, and prebiotic (pre-life) chemistry. This focus groupmakes recommendations and gives advice about astrobiol-ogy missions.
Mission to Early Earth Focus GroupThe search for life beyond Earth requires a concept of theconditions in which life begins and develops. This focusgroup is based on Earth, the only planet where life isknown to exist. This project believes the study of life andthe environment on early Earth is a critical part of makingplans for future space missions.
Impacts Focus GroupThe Impacts Focus Group examines how asteroids, comets,and other materials that have physically impacted the Earthhave influenced the origin, evolution, and extinction of life.
TARGET MISSIONS:PLANETS, MOONS, AND COMETSMarsThe Mars Global Surveyor is now in orbit, gathering infor-mation about Martian surface features, atmosphere, and
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magnetic properties. Another probe currently in orbit is theMars Odyssey, which can determine the planets surfacecomposition, including the presence of water and ice.
By comparing Earth to Mars, scientists will betterunderstand Earths history and perhaps its future. The datawill also help in planning future missions, says one writerfor the Ames Research Center Website.
Each of NASAs Mars exploration rovers carries a set ofinstruments designed to search for evidence of life in theplanets past. Future projects on Mars include searching forwater, studies of environmental changes, and testing forfossils. A new scientific report from NASA says primitivelife-forms may once have existed on Mars, perhaps a formof bacteria. Scientists have found magnetite crystals in aMartian meteorite. Bacteria on Earth use magnetite crystalsto find food and energy.
EuropaThe discovery of an ocean beneath the icy surface ofEuropa (Figure 4.1) has created new goals for astrobiology.Goals are set to determine the moons prebiotic organic his-tory and search for life on Europa.
Future missions to Europa will be the testing ground forhydrobotsremote-controlled submarines that couldmelt through the ice and explore the undersea realm.
TitanSaturns Largest MoonTitan is the only moon in our solar system with a denseatmosphere and a sophisticated organic chemistry. TheCassini orbiter sent the Huygens Space Probe into theatmosphere of Titan to take measurements. For many years,biochemists will closely study the chemistry of this unusual
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moon, to determine whether it has the ability to supportlife.
Comets Comets may have had an impact on life on early Earth,according to scientific studies. There are theories that suggestthat the water and ice from comets could have formed theworlds oceans, and may also have seeded the early Earthwith organic materialthe stuff needed for life to begin.
Muses The interplanetary space probe Muses (and its rover) is onits way to Asteroid 1998SF36. It was launched in May
31What Do SETI Scientists Do?
Figure 4.1 Jupiter is seen here with its four moons (Europa is theone at the far right).
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2003, to arrive at the asteroid in September 2005. Its rover,Muses-CN, will collect up to three samples from the aster-oid and return them to Earth in 2007. This is a joint mis-sion with the Japanese Space Agency, the Institute ofSpace and Astronautical Science (ISAS; also of Japan),and NASA. The tiny NASA rover for this mission is thesmallest rover ever to fly in space. Muses-CN is a 2.2-pound (1-kg), hopping-and-rolling nanorover, which workslike a robot.
Planets Outside Our Solar System The Spitzer Space Telescope (an infrared telescope) is anew, highly sensitive telescope that will use the infraredspectrum for astrobiology studies such as protoplane-tary and planetary debris and surveys of the early universe.
JOB DESCRIPTIONSAstronomers and Astrophysicists Astronomers and astrophysicists try to understand the phys-ical nature and origin of stars and other celestial bodies.Some of the main questions they ask are: How are starsborn? What happens when a star dies? How did the universebegin? What is the rotation of planets, moons, and stars?(Rotation is how fast a planet spins on its axis.) What causesquasars, pulsars, and nebulae? Scientists have been able toform some ideas about these space phenomena. For exam-ple, theyve learned that when a star dies, depending on itssize, it may end in a supernova, eventually becoming a neu-tron star or a black hole. Smaller stars get smaller in sizeover thousands of years. As they run out of fuel, they laterbecome red giants, and eventually, white dwarfs. Scientists
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gather information by directly observing the skies and bylooking at the research of other scientists, including amateurastronomers.
Space PhysicistsSpace physicists investigate charged particles, magneticfields, and other invisible parts of outer space. They checkout the suns composition, its outer atmospheres, and solarwinds. They also study the suns effect on Earth and theother planets in our solar system. Space physicists askquestions such as: What is space weather? What is inter-planetary space (the space between the planets) made of?
SETI Chemists and BiochemistsSETI chemists study the Earths chemistry to help themunderstand how life might develop elsewhere in the uni-verse. For example, at NASAs Ames Research Center inMoffet Field, California, scientists created freezing condi-tions similar to those in gigantic interstellar clouds of dust,gas, and ice that are the birthplaces of new stars and plan-ets, and then exposed these conditions and matter to ultra-violet (UV) light. Their experiment resulted in theformation of a group of amino acids similar to those foundon Earth. Amino acids are essential ingredients for life tobegin.
33What Do SETI Scientists Do?
Gas Giants
U.S. astronomers have recently discovered five gas-giantplanets outside our solar system. This makes 139 knownplanets orbiting stars other than the sun. The findings werebased on observations made at the Keck Observatory.
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SETI biochemists study Earth microbes and plants, tounderstand the chemistry and structure of living organismsthat might exist in space.
Paleontologists Paleontologists in SETI investigate fossils of microorgan-isms, rates of evolution, and changes in prehistoric landsand planets in our solar system. Paleontologists are cur-rently studying fossils here on Earth, to help them under-stand ancient life-forms on other planets. By studyingancient fossil evidence found at the hot springs in Yellow-stone Park, for example, paleontologists might draw con-clusions about how early life developed on Earth.
AstrobiologistsAn astrobiologist studies the earliest life-forms on Earth andcompares the conditions in which they lived to the surfacegeology of planets and moons. Recently, astrobiologists havebegun to study the ocean chemistry of Jupiters moon Europa.They want to know: How does life begin and evolve? Whatis the future of life on Earth and beyond? Astrobiologiststry to answer these questions, and also try to figure out howlife can survive in extreme environments, such as Mars.
Computer Software EngineersSoftware engineers in SETI develop software programsthat tell computers what to look for during radio telescopesearches (this is called application software). Theydesign systems that make research more efficient and accu-rate. They work closely with the research team, since com-puters are the main communication device betweenscientists and the telescopes that receive information.
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The field of SETI is broadening into the area of astrobi-ology. NASA has a recently established division of Astro-biology Research, which includes SETI-related missions,creating new employment possibilities for scientists.
Job descriptions of SETI scientists and astrobiologistsvary widely, ranging from involvement in the movie indus-try to scientific study of deep space. Refer to the Appendixfor job listings related to SETI and astrobiology at NASA.
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RADIO TELESCOPES
CAN YOU IMAGINE a satellite dish as big as a football field?How about 20 football fields? Thats the size of the AreciboObservatory Telescope dish in Puerto Rico: 1,000 feet (305meters) in diameter. The Arecibo dish is the largest single-dishradio telescope in the world (Figure 5.1). Scientists use theArecibo dish and several other radio telescopes to conduct theirresearch.
Placing radio telescopes in the right spots on Earth (such asArecibos location near the equator) allows astronomers andscientists to see the largest sections of sky. Radio telescope
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sites are where SETI scientists and astronomers do most oftheir field work, and are perhaps the most important tool ofSETI science.
When SETI scientists look for evidence of advanced lifeon other planets, they listen for radio and microwave signals.Theyve decided that any advanced civilization that mightexist would know that radio waves are the clearest paththrough interstellar space, and, like Earth, would use thatpath to contact other worlds. Radio waves travel at the speedof light, and penetrate clouds of dust, interstellar clouds, andeven some solid materials, making them a logical tool.
Most of what we know about stars and planets has beenbrought to us by light waves, also known as the visible lightspectrum. However, this is the smallest part of the electro-magnetic spectrum.
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Figure 5.1 The Arecibo radio telescope in Puerto Rico is the largestsingle-dish telescope in the world.
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Infrared and radio waves have brought scientists a lotmore information about the universe, because they carryinformation that cant be obtained visually, such as theexistence of distant sun-like stars and planets. Radio tele-scopes were the first nonvisual tool (optical telescopescame first) for exploring the universe.
Radio telescopes, which were first used in the 1940s,scan the skies for radio wave signals. They collect the datathat would be missed if visible light were the only form thatpossible messages from life in space could take. Many pre-viously hidden planets have been detected because of radiotelescopes.
Cosmic microwave background noise was first foundwith radio telescopes, by U.S. radio engineer Karl Janskyin 1932. This background noise is present everywhere inthe universe, and contains remnants of the Big Bang, whichmany scientists believe is the origin of the universe itself.
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Waves
The electromagnetic spectrum is made of radio waves,microwaves, infrared waves, visible light waves, ultra-violet, X rays, and gamma rays. All waves in the electro-magnetic spectrum are made up of photons, which areparticles of light. Wave frequencies are also called oscil-lations. Oscillations describe how often a wave com-pletes a cycle, over time. Radio waves have the longestwavelengths in the spectrum, some of them as long as afootball field (100 yards [91 meters]). Radio waves bringmusic to your radio, images to your television, and con-versations over your cellular phone. Antennas receiveradio wave signals, which are broadcast from television,radio, or cellular towers.
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How Radio Telescopes WorkRadio telescopes of all types use a reflecting dish, some-what like a satellite dish for televisions, but much larger.Radio telescopes are big, because radio waves are big. If sci-entists hope to create clear images from the radio waves,they must have equipment large enough to receive them.
Objects in space give off radio wave signals (all objects inspace give off electromagnetic waveseven you). These sig-nals strike the reflecting surface of the dish, which is madeof metal. These reflected waves are concentrated andfocused through receivers, which use wave guides that arespecially tuned to the radio or microwave frequencies.
Signal processors in the telescope are extremely sensi-tive to the distances and amplitude of the radio waves,which reveal plains, mountains, valleys, and the quality ofthe atmosphere of distant planets.
Years ago, scientists were able to learn that the moons sur-face was covered in sand, long before astronauts ever walkedon it, because radio waves that the moon gave off revealed itsgrain-like surface. Flares and spots on the sun send strongradio waves that told scientists how high and wide they are.
AreciboArecibo Observatory in Puerto Rico has the greatest electro-magnetic-wave-gathering capacity of any radio telescope inthe world. Its 1,000-foot-diameter dish is set inside anancient limestone crater, creating a convenient natural set-ting. Astronomers, astrobiologists, and SETI scientistsfrom all over the globe compete for time at the Arecibodish. Visiting scientists make proposals to the staff at thesite, who assign time according to the merits of the researchproposals.
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The Arecibo dish can detect asteroids, meteors, distantgalaxies, quasars, and pulsars. SETI scientists visit the dishat Arecibo several times a year, to take advantage of itslocation near the equator, which is ideal for observing allplanets in the solar system, and the outermost layer of theEarths atmosphere, the ionosphere.
Green Bank Radio TelescopeThe Green Bank radio telescope is part of the NationalRadio Astronomy Observatory (NRAO), an institution setup by the U.S. government, which designs and builds itsown telescopes for scientific uses around the world. TheGreen Bank telescope is located in Green Bank, West Vir-ginia. Its the worlds largest fully mobile (steerable) radiotelescope. It can be aimed at any part of the sky.
Very Large Array The Very Large Array in Socorro, New Mexico, is a collec-tion of 27 individual 25-meter, 230-ton parabolic dishes,spread over an area in a way that lets it receive the mostradio and microwave signals possible (Figure 5.2). Like theGreen Bank Radio Telescope, the Very Large Array is partof the National Radio Astronomy Observatory.
Allen Telescope ArrayThe Allen Telescope Array is the worlds largest radio tele-scope. It consists of several hundred small satellite dishes.(See Chapter 6 for more information.)
OPTICAL SETI TELESCOPESOptical SETI (OSETI) is another choice for searching theskies. OSETI seeks pulses of light in the visible or infrared
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range of the electromagnetic spectrum. With optical tele-scopes, SETI scientists look for brief, powerful pulses oflight from other planets. They use light detectors calledphotomultipliers to look for short laser pulses that last forless than one-billionth of a second. These short pulses oflight can be easily distinguished from naturally occurringlight, because they are so brief. Scientists have determinedthat receiving these signals would indicate contact withextraterrestrial intelligence.
In 2003, scientists at the University of Californias LickObservatory, the SETI Institute, and the University of Cal-ifornia at Berkeley joined together to support a project thatuses a new pulse-detection system. It can find laser bea-cons from civilizations that might exist many light yearsaway from Earth.
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Figure 5.2 The Very Large Array in New Mexico consists of 27 largedish telescopes.
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Past optical SETI searches have had problems with falsealarms, because of Earth-based light that looked like pulsesfrom outer space. In a press release, SETI Institute chairmanFrank Drake said the Lick optical SETI project is perhapsthe most sensitive Optical SETI search yet undertaken.
Stuart Kingsley is a well-known optical SETI scientistwho has been conducting his own experiments for manyyears. Recently, his research has been embraced by othersin the SETI field. He has convinced some scientists thatoptical SETI is an effective tool because powerful lensescan receive pulsed laser beacons. Any type of signal,whether light flashes or radio waves, if repeated, might bean indication of ETI.
Keck InterferometerThe Keck Interferometer is a system that links two 10-meter optical telescopes to create the worlds most power-ful optical telescope system. The Keck Interferometer isused to search for planets around nearby stars. It combineslight from the two telescopes to measure emissions fromdust orbiting stars.
INFRARED TELESCOPES Spitzer TelescopeInfrared telescopes collect information about planetary sur-faces. Telescope sensors record the information with infraredimages, which are beyond visible wavelengths. Colors arethen assigned to the different wavelengths, and these varia-tions in color make the image visible. These colors can showclimate changes and surface biology. The NASA InfraredTelescope Facility at the Institute for Astronomy at the Uni-versity of Hawaii has recently been able to determine the
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presence of methane on Mars by a close reading of infraredimages. Methane gas is a by-product of microscopic life-forms, and is associated with the presence of life, which isuseful information to SETI.
COMPUTERSAfter telescopes, the next most important tool of SETI sci-ence is computers. SETI scientists use supercomputers forprocessing large chunks of data, and smaller computers forgraphic displays, calculations, and software programming.Without computers, understanding the chemistry and sig-nals coming from the universe would be impossible.Astronomy and physics are intimately connected, becausethe universe is based on the laws of physics. Attempting tounderstand billions of frequencies that arrive continuouslyrequires lots of calculations.
At Arecibo, Project Phoenix computers are uniquelydesigned to analyze microwave signals sent by receiverswithin the dish. Teams of scientists program the computersso theyll recognize which stars to search, or to have thecomputer search more than one star at a time. The com-puters swallow a big chunk of radio information, says theSETI Institutes Jill Tarter. They slice it up into tiny littlechannels, kind of like slicing a salami. They carefully ana-lyze every single piece to see if theres a pattern.
SEARCH STRATEGIES ARE TOOLS, TOOIn a universe with billions of stars to choose from, SETIscientists face a challenge to find the best method forsearching for radio signals. They must decide where andhow to look. Two types of search strategies are used byboth optical and radio SETI science, to make the most of
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their efforts. They are called Targeted Search and the FullSky Survey.
Targeted SearchTargeted Search surveys the sky for stars closest to Earth,and most similar in size to our sun. Scientists pick olderstars for the Targeted Search, since it can take billions ofyears for life to develop on planets. They can estimate theage of a star by the amount of activity in the radio signals.Young stars are more active.
The Targeted Search allows for more detailed investiga-tions, since more can be seen and heard when objects arenearer. Most scientists think water is needed for life todevelop. If a planet were too close to a star, water wouldboil and evaporate, and the planet would not be a good can-didate for further study. If a planet were too far away froma star, then the lack of light and warmth would likely pre-vent life from developing there. Scientists look for evi-dence of conditions favorable to all kinds of life, however.Extreme conditions do not necessarily eliminate a planet,but conditions must fall within certain limits. The TargetedSearch looks for signals from 1,000 to 2,000 stars at a time.The major limitation of the Targeted Search is that it leavesout large portions of the sky. Project Phoenix is a large-scale Targeted Sky project.
Full Sky SurveyThe Full Sky Survey search strategy doesnt leave out anypart of the sky. Its aim is to check for unusual signals fromas many stars as possible. It has many different names,including Full Sky, All Sky, Sky Survey, and Wide-Field,but they all refer to the same basic method in which large
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areas of sky are surveyed. Project Argus is a Full Sky Sur-vey Project.
Scientists believe these two types of searches worktogether. Targeted Searches have the ability to focus onlikely candidates for ETI, but if all searches were focusedthis way, scientists might miss candidate stars that are far-ther away.
For both search strategies, if telescopes detect an unusualsignal from a particular section of the sky, they tell a sec-ond telescope somewhere else in the world to scan the samesection of sky. If the signal is false (accidental, or comingfrom Earth-based background noise), it will not be detectedby the second telescope.
LABORATORIESSETI scientists use microscopes, particle accelerators,test tubes, and a collection of chemicals for freezing andheating up matter in laboratories, to test their theories aboutlife on Earth and other planets.
NASA Astrobiology scientists study salt-loving and UV-resistant microorganisms in the lab, to learn about the sur-vival and biological evolution of life in space. SETIscientists also use signal-processing labs, which areequipped with computers and electronics equipment tostudy incoming signals from radio telescope searches.
OTHER TOOLSSETI scientists gather information from the tools of NASAand the European Space Agency. Space probes fromthese programs, such as the Hubble Space Telescope(HST) (Figure 5.3), are helpful to SETI, because scientistscan check the galaxy and its celestial bodies without inter-
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ference from the Earths atmosphere. HST was the first tofind evidence that there were planets around other stars, amajor discovery for SETI in 1995. Swiss astronomersMichael Mayor and Didier Queloz discovered the planetsorbit around the star 51 Pegasi.
Huygens Space Probe, which landed on Saturns Titanmoon in January 2005, has analyzed Titans atmosphereand sent photographs back to Earth. It has revealed anatmosphere made up of nitrogen and methane, which tellsus that life may have existed there at some point. SETI uses
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Figure 5.3 The Hubble Space Telescope has been an extremely valu-able tool for scientists involved in SETI research.
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all of this data to draw conclusions about life on planetselsewhere in the universe.
Space vehicles, such as the twin Mars rovers, Spirit andOpportunity, send both visible and infrared images back toEarth. These are analyzed for signs of life by SETI scientists.
Satellites and optical telescopes fitted with photometerscheck for the presence of Earth-sized planets by focusingon certain stars, and looking for changes in that particularstars light emissions. A slight dimming in light indicatesthat a planet is revolving around the star.
Its important to note that SETI scientists do not investi-gate reports of aliens or UFOs, since these do not involvesystematic scientific observation.
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NASAMany SETI scientists work as astrobiologists for NASAsAstrobiology Institute (NAI), with its base operations at theAmes Research Center in Moffet Field, California. NAI is avirtual institute, made up of 15 teams, each engaged in astro-biology research under the direction of NASA. Each teamworks from its own facility, mainly from universities, locatedall over the United States.
For scientists with revolutionary ideas about aeronautics andspace concepts, there is the NASA Institute for Advanced Con-cepts (NIAC). This organization encourages scientists to think
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decades into the future, in pursuit of concepts that willleapfrog the evolution of current aerospace systems, saysthe NIAC Website. The projects currently under way atthese centers of SETI and astrobiology study space explo-ration with a broad range of scientific disciplines and tech-nologies to find answers about life in the universe.
In addition to NASAs National Astrobiology Institute,the Jet Propulsion Laboratory (whose missions includeMars exploration rovers and the Spitzer Space Telescope)and Johnson Space Center (the lead center for space shut-tle activities), many universities, such as the University ofCalifornia at Berkeley, Harvard University, and PrincetonUniversity, are involved in astrobiology and SETI projects.
SETI INSTITUTEThe SETI Institute mission statement says its purpose is toexplore, understand and explain the origin, nature andprevalence of life in the Universe. The SETI Institute is aprivate organization. That means it receives its money forresearch from individuals donations, and not from thegovernment. Most American SETI scientists spend part ofthe year working at the SETI Institute in Mountain View,California, teaching and doing research. The SETI Institutecollaborates with NASA and other organizations on a vari-ety of topics, employing SETI scientists from many walksof life.
CURRENT SETI INSTITUTE PROJECTSThe Allen Telescope Array (ATA)Two executives from the Microsoft Corporation have madea big investment in SETI. Paul Allen (a cofounder ofMicrosoft) and Nathan Myhrvold (the former chief tech-
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nology officer for the company) are fascinated by SETIresearch. In fact, theyve given the SETI Institute $12.5million to develop a radio telescope dedicated entirely toSETI and radio astronomy. Its called the Allen TelescopeArray, after Paul Allen.
The Allen Telescope Array consists of 350 individualsatellite dishes. The project is located at the Hat CreekRadio Observatory near the University of California atBerkeley. With its 350 satellite dishes, the ATA is able tostudy many areas of the sky at once, using more channels.It is in operation 24 hours a day, 7 days a week. The com-bination of these features will make it possible to study100,000, or maybe even a million, nearby stars.
Project PhoenixProject Phoenix was developed from NASAs TargetedSearch Project. SETI Institute took over the program afterNASA lost its government funding for SETI in 1994. Project Phoenix uses the worlds largest radio telescopesto study the nearest sun-like stars, one by one. ProjectPhoenix workers search for artificially produced signals(signals made by technological devices) in themicrowave spectrum. According to the SETI Institute,Project Phoenixs ability to detect and analyze slowlydrifting signals is the most comprehensive in the worldtoday.
Twice a year, SETI Institute scientists visit the worldslargest radio telescope, located in Arecibo, Puerto Rico, aspart of Project Phoenix. At Arecibo, there are cabins set upfor the scientists to live in during their stay. They workaround the clock in shifts, taking turns at the computer,analyzing radio signals, and observing the sky.
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ObservatoriesObservatories are places where astronomy is put intoaction. They are designed for visual observation of the uni-verse, and are usually associated with university programsin astronomy and OSETI (optical SETI). Some examplesare the Hat Creek Observatory at the University of Califor-nia at Berkeley; the FitzRandolph Observatory at PrincetonUniversity in Princeton, New Jersey; the Harvard Tele-scope, located on the Harvard campus in Cambridge, Mass-achusetts; and the Lick Observatory at Mount Hamiltonabove San Jose, California.
NASAs Jet Propulsion LaboratoryPlanetQuest is the astrobiology center for JPL. Its missionis the search for another Earth. Current projects underway at PlanetQuest are the Space Interferometry Mission(SIM) and the Terrestrial Planet Finder (TPF). The SIMproject involves a spacecraft, to be launched in 2011, whichwill be sent into an Earth-following solar orbit. Its onboardinterferometers are designed to detect the precise dis-
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Lick Observatory
Lick Observatory at University of California, built in1887, was the worlds first mountaintop observatory. Ituses the Nickel 40-inch (102-cm) reflector, and speciallydesigned hardware and software for its light detectorsystem. Lick optical SETI continuously examine star sys-tems and star clusters. Each star is observed for tenminutes, checked for brief light pulses, and then scien-tists move on to the next star. Lick Observatory islocated at the summit of Mount Hamilton, near San Jose.
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tances of stars from Earth in the Milky Way galaxy, with anaccuracy that is hundreds of times greater than before. TheTPF project consists of two separate outer-space observa-tories. One will be launched in 2014 and the other in 2020.The TPF will study all aspects of planets outside our solarsystem: their formation from spinning disks of dust and gasaround newly forming stars, planets orbiting nearby stars,the various sizes, and suitability for supporting life.
PlanetQuests scientific mission is to discover not just afew but thousands of new planets in our galaxy within thenext five years. Some 150 planets with nearby stars havebeen found since 1995, but many are too small and faint tobe seen directly. PlanetQuest scientists determine theirpresence indirectly through a process that requires carefulanalysis of very large amounts of astronomical data.
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JILL TARTER
AS A YOUNG CHILD, SETI scientist Jill Tarter (Figure 7.1),born on January 16, 1944, loved to go fishing and camping inthe Catskills with her father, who eventually told her that sheshould spend more time learning about domestic life in thehome. I thought that was the most unreasonable thing that any-one had ever said to me, Tarter recalls. In Looking for Life inthe Universe, Tarter describes how she later told her father thatshe wanted to become an engineer, aware that this was consid-ered a field for men. This time, he encouraged her, telling herthat hard work would get her wherever she wanted to go.
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Tarter had more stereotypes to break through in highschool. She wanted to take shop (a carpentry class usuallyreserved for boys at the time), but was told she had to takehome economics, so she could learn how to cook and takecare of a household. She ended up taking both classes. Shecredits her mother for being supportive of her choices. Sheadds, I learned early on that the way to get what you wantis to do the extra work. And then people cant say no. Sheexcelled in high school physics, and earned a scholarship toCornell University, where she was the only woman in herclass of 300 male engineering students. It wasnt easy. Sheended up doing her homework alone. However, she felt thatthe experience actually gave her a better education. She fin-ished a five-year engineering program in four years, and
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Figure 7.1 SETI scientist Jill Tarter poses for the camera while shetakes a break from working on the Arecibo telescope.
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decided that astronomy interested her more than engineer-ing. After a few years, she focused on SETI research. Shehas been active at the SETI Institute in a range of leader-ship and scientific roles since 1984. She is happily marriedto Jack Welch, who is in charge of SETI at the Universityof California at Berkeley.
CARL SAGAN: A STAR IN SETIAs a child growing up in Brooklyn, New York, Carl Sagan(Figure 7.2) loved science fiction and became fascinatedwith astronomy when he learned that every star in the uni-verse was actually a sun. His parents always encouragedhim to research his own answers to the many science ques-tions he asked. He earned three degreesbachelors andmasters degrees in physics, and a Ph.D. in both astronomyand astrophysicsall from the University of Chicago.
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Figure 7.2 Carl Sagan, one of the most respected scientists of the 20th
century, helped bring SETI science to the attention of the general public.
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Sagan was among the first scientists to determine that lifehad once existed on Mars. In 1968, Sagan began teachingat Cornell, where he also became the director of the Labo-ratory for Planetary Studies. He became a visiting scientistat the Jet Propulsion Laboratory in Pasadena, California,and helped design and manage the Mariner 2 mission toVenus, Mariner 9 and Viking trips to Mars, the Voyagermission to the outer solar system, and the Galileo missionto Jupiter. Sagan was famous for being a pioneer in the fieldof astrobiology and the search for extraterrestrial life. Heachieved fame by appearing on television programs to dis-cuss astronomy and by creating the popular PBS seriesCosmos, in 1977. He also wrote a novel that was made intoa movie, called Contact, in 1997, starring Jodie Foster (Fig-ure 7.3). The lead character was based on Jill Tarter, theastronomer at the SETI Institute, and a pioneer in her own
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Figure 7.3 In this scene from the movie Contact, Jodie Fosterlistens to radio signals, hoping to hear a pattern that wouldindicate a signal from extraterrestrials.
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right, as one of the first women in the field of SETI. CarlSagan was a cofounder of the Planetary Society, which isinvolved in several SETI projects. His 1977 book, TheDragons of Eden, won the Pulitzer Prize.
FRANK DRAKEFrank Drake (Figure 7.4) was born in Chicago on May 28,1930. Like others in the field of SETI, he showed an earlyinterest in science. He spent hours with radio experimentsand chemistry sets, and as his interest in astronomy grew,he became fascinated with the size of the universe. He alsobegan to wonder about life on other planets. Because of hisparents religious beliefs, however, he didnt pursue thetopic of extraterrestrial life until after he graduated fromhigh school.
While he was a student at Cornell University, Drakeattended a lecture by Otto Struve, a world-renowned astro-physicist. In the lecture, Struve explained evidence forplanetary systems (planets revolving around sun-likestars) beyond our own, in the Milky Way galaxy. Struvealso believed that life could exist on some of these far-awayplanets. Frank Drake was inspired that a scientist of thisstature shared ideas similar to his own.
Drake received his degree in electronics from Cornelland entered the U.S. Navy as an electronics officer in 1956.In the navy, he gained valuable experience with the mostadvanced electronics technologies of the day.
When his navy tour of duty ended, Drake attended Har-vard, initially hoping to study optical astronomy, but thesummer positions he wanted were taken. There was roomin the schools summer program in radio astronomy, how-ever, and he eventually became hooked on the science of
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Figure 7.4 Frank Drake, the founder of the SETI Institute, points tothe sky.
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radio astronomy. When he finished graduate school at Har-vard, he got a job at the National Radio Astronomy Obser-vatory (NRAO) in Green Bank, West Virginia. The firstofficial radio astronomy search took place there, in 1960,under his direction, observing the stars Tau Ceti andEpsilon Eridani.
In 1961, Drake and J. Peter Pearman from the NationalAcademy of Sciences organized the first SETI conference.In preparation for the conference, Drake devised an equa-tion to help the other scientists focus on the key questionsof whether life can exist on other planets. The equationconsiders astronomical, biological, and social factors in itsestimates of the probability of life in a galaxy or planetarysystem.
KEVIN HANDKevin Hand is one of the younger astrobiologists at theSETI Institute, born in 1977. His passion for astronomybegan during his childhood in Vermont, where he campedoutdoors under star-filled skies. He greatly admired hisolder brother, whose deep interest in the world of sciencehad an impact on Hand. These experiences helped shapeHands future. He was also influenced by Carl Sagan, theastrophysicist whose book and television series Cosmos,Hand says, in an interview for the SETI Institutes Voices,connected his direct experience of the natural world withthe science that explained it.
Hand deepened his knowledge in high school, when hewrote a paper for a biology class about life on other plan-ets: I wrote about life on Mars, Europa, the solar system,and searching for planets around other stars. He was notaware of the field of astrobiology at the time, nor that it
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would become his career. To prepare for his high schoolproject, hed read the work of Jill Tarter and Frank Drake,who are now his fellow scientists at the SETI Institute.
By the time Hand entered college, he knew that astro-biology would be his career. There was never a decision,he states, about his desire to use science to explore life onother worlds. It just always had to be.
Hand went on to Stanford University for his Ph.D., andcurrently participates in a NASA internship through theSETI Institute, where he works at SETI Institutes Centerfor the Study of Life in the Universe.
While on Catalina Island (off the coast of California) fora field-study program, Hand met James Cameron, a famousHollywood film producer, who was looking for an astrobi-ologist to join his film project about an exploration to themid-Atlantic ridge, and the East Pacific Rise ofhydrothermal vents. Hydrothermal vents, found deepbelow the oceans surface, are of major interest to SETI.Scientists think the vents are important to the origins oflife, and perhaps the basis for the existence of life on otherplanets. The film, called Aliens of the Deep, explores themicroorganisms that thrive in near-impossible conditions,in complete darkness, with almost no food.
Hands advice to young science enthusiasts who are try-ing to find their career path is: We tell people to let theirteachers know when they need them to slow down, so thestudents have enough time to understand. And we tell themto ask questions, no matter how intimidating it might seem.The exciting side of science really resides in the questions.
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ARE MATH AND SCIENCE your favorite subjects in school? Ifyou often wonder about life in the universe, you may somedayfind yourself at a powerful telescope, searching for ETs.
A SETI scientist is a lot like a detective, looking at clues tofind answers about ETI and life in space. They spend a lot oftime thinking. This might sound a little boring, but if youre aSETI scientist, thinking, wondering, and trying to figure outwhere there might be life in the universe is about as exciting asit gets.
In many ways, SETI science is similar to the pursuits of theearly explorers and discoverers. Like Christopher Columbus,
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SETI scientists have an intense curiosity and a belief thatthere are new worlds out there, despite the lack of hard evi-dence. If you love the unknown, you can apply this to asearch for life in the universe.
CHECK OUT THE UNIVERSEScientists estimate that the universe began with the BigBang, around 14 billion years ago. But the truth is no oneknows for sure how the universe came into being. We doknow that its a big place. Astronomers now estimate thereare 70 sextillion stars in the universethats 70 thousandmillion million million, or 7 with 22 zeroes behind it.
There are at least several billion galaxies in the universe.The nearest galaxy is the Andromeda, which is 2 millionlight years away. The visible universe is roughly 28 billionlight years in diameter. Where is the boundary of the uni-verse, and what lies beyond it? This is what scientists wantto know. Many objects in the night sky are planets, reflect-ing sunlight. Other objects may be comets. You might thinkyou see a star, but are actually seeing a whole galaxy. Theseobjects appear to be close to each other but are actuallyhuge distances apart.
THE RIGHT STUFFCuriosity, determination, and imagination are importantqualities in a SETI scientist. Determination is necessarybecause no signs of ETI have yet been found, and still thescientists do not give up the search. Research projects oftentake years, so you need to be self-motivated and able to stayfocused on your goals. Successful SETI scientists areenthusiastic, honest, and creative. They are passionateabout their work.
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GET A GOOD STARTIf you take plenty of math and science in high school, andeven in middle school, you will be giving yourself a goodstart for a SETI career. You should be good enough at thesesubjects so you dont get left behind when you take collegemath and science classes. If you want a career in SETI anddo not start college with a solid foundation in high schoolmath, it will be hard to catch up.
COLLEGE IS NECESSARY All SETI scientists go to college and receive at least under-graduate degrees in mathematics, biology, physics, chem-istry, or engineering. This builds the foundation for laterstudies in astronomy and astrophysics. SETI scientists usetheir mathematics and physics knowledge to give them adeeper understanding of astronomy and the workings of theuniverse.
SETI scientists can also receive training through studentfellowships, internships, and by volunteering at observato-ries and planetariums.
Math, science studies, and internships are not the onlythings needed for a career in SETI. Successful SETI scien-tists must be able to communicate effectively both inspeech and in writing. SETI research is eventuallydescribed mostly in words, and SETI scientists often pre-sent the results of their studies to the science community bygiving talks on a variety of topics. Scientists need to studyEnglish and writing at the college level, so they can handlethis important aspect of SETI work.
After SETI scientists receive their undergraduatedegrees, most of them go to graduate school for a Ph.D. inastronomy, astrobiology, astrophysics, engineering physics,
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or software engineering. Without a Ph.D., it might be hardto find a job in SETI science.
TRAINING TO BE A SETI SCIENTISTNASA Astrobiology AcademyThe NASA Astrobiology Academy is a unique summerinstitute of higher learning that helps guide future leadersof the U.S. space program by giving them a glimpse of howthe whole system works. The goal is also to train studentsin fields related to astrobiology early in their careers andprovide them with hands-on experience in this excitingfield.
Arizona State University, TempeAstrobiology programs include meteorite studies; researchon the evolution of photosynthesis; fossilization processesin microbial ecosystems; snail-fish ecosystems in springs;and life on Mars and Europa.
University of Colorado, BoulderThe Center for Astrobiology at the University of Coloradohas focused on the formation of stars and planets; planetaryatmospheres, clouds, and hazes; the origin of life; andhydrothermal systems and weathering.
Harvard UniversityStudies in SETI science at Harvard include the evolution ofthe early biosphere, micropaleontology, geochemistry oforganics and trace elements, and tectonics.
Pennsylvania State UniversityPenn State Astrobiology Research Center studies include
64 SETI Scientist
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the early environment of Earth, including the atmosphereand oceans, as well as the atmospheres of other planets.
YOU CAN PARTICIPATE IN SETI SCIENCEHome computers have the ability to analyze information.Scientists at the University of California at Berkeley createdsoftware for home computers so that people (anyonenotjust scientistscan take part) can download SETI@homesoftware from the Internet and place it in a screensaverprogram. When these home computers are not in use,SETI@home software goes into action, and uses that timeto analyze SERENDIP data. When millions of home com-puters are participating in SETI@home, they act as one verylarge supercomputer.
The process works like this:
1. Data is collected from the Arecibo dish in Puerto Rico.
2. Data is stored on a disk with notes such as time, date,
and sky coordinates.
3. The data is divided into small chunks of information,
so that home computers can process it.
4. The SETI@home program on home computers down-
loads the information from computer servers at the
University of California at Berkeley.
5. When the home computer is not in use, it switches to the
SETI@home screensaver program and analyzes the infor-
mation. This takes anywhere from 10 to 20 hours, depend-
ing on the size of the home computers microprocessor.
6. Home computers upload the results to the University of
California at Berkeley, and make note of any hits
(hits are signs of possible ETs).
In 2005, 2 million people were participating in SETI@home.
65Do You Want a Career in SETI Science?
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APPENDIX
Advanced Projects Design TeamLeader
Aeroacoustics Engineer
Aerodynamics Engineer
Aeromechanics Engineer
Aeronautical Engineer
Aeronautics and AerospaceTechnologist
Aerospace Engineer
Aerospace Engineer Technician
Aerospace Optical Engineer
Aerospace Research Engineer
Aerospace Systems Safety ResearchAssistant
Aerospace Technologist
Airborne Telescope Operator
Analytical Chemist
Applied Meteorology
Assistant Astronomer
Assistant Branch Chief
Assistant Science Coordinator
Assistant Superintendent
Associate Producer
Associate Staff Scientist
Astrobiologist
Astronaut
Astronomer
Astronomy Educator
Astrophysicist
Atmospheric Physicist
Atmospheric Structure Investigator
Biocomputation Center DeputyDirector
Bioengineer
Biological Engineer
Biologist
Biomedical Engineer
Biomedical Technician
Branch Chief
Center Controller
Chemical Engineer
Chemist
Chief of Biological & ChemicalAnalysis Laboratories
Chief of Guidance and PropulsionSystems
Chief of Life Sciences Division
Chief Project Engineer
Chief Toxicologist
Cinematographer
Civil Engineer
Cognizant Engineer
College Intern
Commander
Computational Fluid Dynamicist
Computational Fluid DynamicsEngineer
Computer Engineer
Computer Programmer
Computer Scientist
Computer Systems Engineer
Computer Systems Technician
List of Current Job Titles and Occupations on file at NASA
A background in physics, biology, mechanical and electrical engineering,math, software engineering, or astrobiology qualifies applicants for manyof these positions.
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Computer Technician
Conceptual Aircraft Designer
Congressional Staff Member
Crew Chief
Crew Coordinator
Crew Training
Crew Training Coordinator
Curriculum Specialist
Data Communications Engineer
Data Management Team
Data Systems Specialist
Deep Space Tracking NetworkOperations Project Engineer(NOPE)
Deputy Chief of Propulsion and FluidSystems Branch
Deputy Chief, Systems DivisionMission Operations Directorate
Deputy Director of Aeronautics
Deputy Director of Operations,Research and DevelopmentServices
Deputy Manager of Payloads Office
Deputy Navigation Team Chief
Deputy Uplink Systems Engineer
Design Engineer
Design Lead
Development Group Leader
Director of Development, SpaceCenter Houston
Director of Flight Operations
Director of Public Relations
Director, Astrobiology and SpaceResearch
Director, California Air & SpaceCenter Teacher Institute
Director, Counseling andPsychological Services Center
Director, NASA Life SciencesDivision
Dive Specialist, Neutral BuoyancyLab (NBL)
Division Chief
Education Specialist
Electrical Designs Engineer
Electrical Engineer
Electrical Operations Engineer
Electrical Power System/Thermal
Electrical Supervisor
Electronics Engineer
Engineer
Engineering Analyst
Engineering Assistant, NASAsSHARP Program
Engineering Manager
Engineering Technician
Engineering Test Pilot
Environment Control and Life SupportSystems Engineer
Environmental Physiologist
Environmental Protection Specialist
Environmental Specialist
Environmentalist
Exercise Physiologist
Exobiologist
Experiment Integration Engineer
Experiment Processing Engineer
Experiment Support Scientist/Microbiology Coordinator
Experiment Systems Manager
Geophysicist
Hardware Engineer
Hardware Project Engineer
Hazardous Robotics Specialist
High-Energy Astrophysicist
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HST Astronomer
Journalist
K12 Outreach Support Personnel
Knowledge Engineer
Laboratory Manager
Lander Camera Support Personnel
Launch Site Support Office Personnel
Launch to Activation Procedures Lead
Lead Altimetry Analyst
Lead Mechanical Engineer
Lead Mechanical Technician
Lead Ops planner, Mission OperationsDirectorate
Lead Robotics and Avionics Engineer
Lead Schedule Integration Engineer
Lead Shuttle Systems Inspector
Lead, Space Station Power ResourceManagement Team
Leader of the Test Engineering Group
Life Science Space ExperimentGround Lab LogisticsCoordinator
Life Science Specialist
Life Sciences Division Deputy Chief
Life Sciences Education ProgramsCoordinator
Life Sciences Outreach OfficePersonnel
Life Sciences Program Manager
Local Controller
Logistics Operations Manager
Magnetometer (MAG) ScienceCoordinator
Manager Mars Exploration ProgramEducation
Manager of Mars ExplorationProgram
Manager, Galileo AdministrativeOffice
Manager, Mars Sample Return Lander
Manager, Space Shuttle Office
Mars Atmosphere InterdisciplinaryScientist
Mars Exploration Program Architect
MARS Outreach Program ProjectCoordinator
Material Research Engineer
Materials Engineer
Materials Scientist
Mathematical Researcher
Mechanical Design Engineer
Mechanical Engineer
Mechanical Instrumentation Tech
Mechanical Systems Engineer
Mechanical Technician, ShuttleSystems
Microbial Ecologist
Mission Commander
Multimedia Education Specialist
Multimedia Specialist
National Research Council Post-Doctoral Fellow
National Science FoundationRepresentative, Palmer Station
Navigation Team Leader
Navigator
Network Engineer
Neurobiologist
Neuroscience Researcher
New Space Transportation Developer
NTSB/FAA Investigator
Numerical Software Engineer
Nutritionist
Observational Infrared Astronomer
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69
Observing Assistant
Oceanographer
Operations Lead
Operations Management
Operations Servicing Mission
Operations, Rover
Optical Engineer, Rover
Orbital Debris Scientist
Orbital Engineering Team
Orbiter Operations Group Lead
Orbiter Processor
Orbiter Test Conductor
Ornithologist
Outreach Program Manager for LifeSciences
Outreach Specialist
Payload Project Manager
Payload Project Scientist
Photopolarimeter RadiometerInstrument Engineer
Photopolarimeter Radiometer ScienceCoordinator
Physicist
Physics Research Associate
Physiologist
Pictures/Remote Sensing Specialist
Pilot
Planetary Geologist
Planetary Scientist
Plasma Wave Assistant ScienceCoordinator
Power, Heating, Articulation, Lightingand Controls Officer
Principal Investigator
Principal Scientist
Probe Deputy Manager
Professor, Adventure Education
Program Manager
Program Planning Specialist
Program Scientist
Project Engineer
Project Engineer, HardwareDevelopment
Project Engineer, Thermal Control
Project Manager
Project Scientist
Project Teacher
Propulsion Engineer
Psychophysiologist
Radio Astronomer
Real-Time Operations Lead
Research Instrument Maker
Research Assistant
Research Associate
Research Astrophysicist
Research Engineer
Research Engineer, MechanicalSystems
Research Nutritionist
Research Physicist
Research Pilot
Research Scientist
Science Instruments Specialist
Science Planning Coordinator
Sciences Requirements Manager
Scientific Director
Scientist
Senior Scientist
Senior Software Engineer
Senior Specialist Engineer
Senior Technical Trainer
Sequence Integration Engineer
Shuttle Project Engineering
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Shuttle Structures and TransportersEngineer
Shuttle Test Director
Simulation Supervisor
Software Development Lead
Software Engineer
Software Operations Engineer
Software Safety and MissionAssurance Engineer
Solar Physicist
Solar Scientist
Space Farming Engineer
Space Flight Technician
Space Flight Training Specialist
Space Physicist
Space Physicist, Space RadiationAnalysis
Space Physiology
Space Plasma Physicist
Space Scientist
Space Shuttle Crew
Space Shuttle Remote ManipulatorSystem Training Instructor
Space Station Robotics Instructor
Space Station Utilization Division
Space Suit Project Engineer
Spacecraft Design Engineer
Spacecraft Systems Engineer
System Design Engineer
System Engineer/Integrator
System Safety Engineer
System Safety, Reliability & QualityAssurance Lead
Systems Engineer
Systems Management
Systems Verification
Teacher
Team Manager, ISS MissionEvaluation
Technical Advisor, Earth: FinalConflict Television Series
Technical Integration Engineer withSpace Station
Technical Leader for Space StationOutreach Group
Technical Writer
Technician
Technology Transfer Specialist
Test Engineer
Test Project Engineer
Thermal Protection System/ShuttleUpgrades Specialist
Trajectory and Aerobraking DesignAnalyst
Trajectory Optimization Engineer
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Amplitude: The strength of a signal.
Asteroid: A small rocky celestial body found between the orbits of Marsand Jupiter.
Astrobiology: The search for and study of life in space.
Bacteria: Single-celled or noncellular organisms that can only be seenwith a microscope.
Bandwidth: The numerical difference between the upper and lower fre-quencies of a band of electromagnetic radiation, especially anassigned range of radio frequencies.
Big Bang: A theory about the origins of the universe.
Biosphere: Living things and their environment.
Black hole: A celestial object with such a strong gravitational field thateven light cannot escape.
Celestial bodies: Planets, stars, comets, and moons.
Channels: Bands of frequency used for communication.
Concept: A scheme or plan.
Cosmic microwave background noise: Microwave radiation from outer-space, related to the Big Bang, stars, and planets.
East Pacific Rise: Mid-ocean ridge system extending from New Zealandto the coast of Mexico; a site of much volcanic and hydrothermalactivity.
Electromagnetic spectrum: The entire range of wavelengths or frequen-cies of electromagnetic radiation, extending from gamma rays to thelongest radio waves and including visible light.
Emission: Electromagnetic waves radiated by an antenna or a celestialbody.
European Space Agency: Europes space exploration program, whichincludes 16 European nations.
Evolution: A gradual process in which something changes into a differentand usually more complex form.
Extrasolar: Outside the solar system.
Extraterrestrial: Originating, located, or occurring outside Earth or itsatmosphere.
Frequencies: How often a wavelength completes a cycle over time.
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GLOSSARY
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Full Sky Survey: Telescope searches that include the full sky.
Gamma Rays: High energy, very short wavelength electromagnetic radia-tion that can be generated by nuclear reactions.
Gas-giant planets: Jupiter, Saturn, Uranus, and Neptune; gas giants arelarge planets made mostly of hydrogen and helium gas.
Geochemistry: Study of the chemical changes of the Earth.
Hubble Space Telescope (HST): Launched in 1990, HST was the firstspace-based optical telescope.
Huygens Space Probe: A spacecraft consisting of an orbiter and a probe,launched in 1997 and arrived at Saturn in 2004.
Hydrobots: Remote-controlled submarines that burrow into the ground toexplore underground oceans on other planets.
Hydrothermal vents: Openings in a planets surface where geothermally(heated underground) heated water emerges.
Infrared telescope: A telescope designed to detect radiation in theinfrared range of the electromagnetic spectrum.
Interferometers: Devices that use interruptions in waves to determine dis-tance or wavelength.
Interstellar gases: Gases that exist between or among the stars consistingmostly of helium and hydrogen.
Interstellar space: Space between the stars.
Ionosphere: Region of Earths atmosphere at 50 to 300 miles (81483km) above the surface, dominated by electrically charged or ionizedatoms.
Laser beacon: An instrument used in optical SETI; it emits a single pow-erful laser beam.
Magnetosphere: The magnetic field around a planet, located above theplanets top layer of atmosphere.
Microorganisms: Also called microbes; organisms too small to be seenwithout a microscope.
Micropaleontology: The study of microscopic fossils.
Microprocessor: A chip that carries the main logic programs of a com-puter; the central processing unit (CPU).
Microwave spectrum: Microwave part of electromagnetic spectrum, notvisible to the human eye.
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Mid-Atlantic ridge: A part of the mid-ocean ridge system that extendsfrom north to south through the center of the Atlantic Ocean.
Milky Way: The galaxy in which our solar system is located.
Nebulae: Interstellar clouds of dust and gases.
Neutron star: A celestial object made up of tightly packed neutrons.
Optical SETI: The branch of extraterrestrial search that uses optical tele-scopes and laser beacons.
Orbit: The path taken by a celestial body during its revolution aroundanother body.
Organic chemistry: The chemistry of carbon compounds, the basis of lifeon Earth.
Oscillation: Process of something swinging or moving regularly back andforth.
Parabolic: Bowl-shaped.
Particle accelerator: A device used by particle physicists to speed up particles.
Photometers: An instrument used for measuring the intensity of light.
Photomultipliers: A photoelectric instrument that amplifies electrons.
Photons: An amount of electromagnetic energy.
Photosynthesis: Process of plant respiration in which carbon dioxide istaken in and oxygen is released.
Planetariums: A building with a revolving projector that simulates thesun, moon, and stars.
Planetary climatology: The science dealing with climate on other planets.
Planetary debris: Small pieces of planetary material, broken into piecesby collisions.
Planetary radar: A process of detecting planets by using reflected radiowaves.
Planetary systems: Planet or planets orbiting a star.
Plasma: A collection of charged particles that has about equal numbers ofpositive ions and electrons.
Prebiotic: The conditions before life began to form.
Protoplanetary: Early formation of a planet.
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Pulsar: Celestial objects, thought to