DOCSLIB.ORG

Constraining the Discovery Space for Artificial Interstellar Signals

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text
Constraining the Discovery Space for Artificial Interstellar Signals Constraining the discovery space for artificial interstellar signals Ian S. Morrison A thesis in fulfilment of the requirements for the degree of Doctor of Philosophy School of Physics Faculty of Science July 2017 Constraining the discovery space for artificial interstellar signals THE UNIVERSITY OF NEW SOUTH WALES Thesis/Dissertation Sheet Surname or Family name: Morrison First name: Ian Other name/s: Stuart Abbreviation for degree as given in the University calendar: 1890 Physics School: Physics Faculty: Science Title: Constraining the discovery space for artificial interstellar signals Abstract: After more than 50 years of searching the skies across the electromagnetic spectrum, no evidence has yet been found for the existence of extraterrestrial life, let alone a signature that could be attributed to an intelligent and technological extraterrestrial civilisation. Proposed explanations range from the non-existence of such putative civilisations, to the likelihood that the search has barely "scratched the surface" in terms of covering the entire discovery space. The present work is premised on the latter position, and its central thesis is that most searches conducted thus far have been disadvantaged by sub-optimal design. In general, they have (1) not targeted the most appropriate signal types; (2) not targeted the region of the electromagnetic spectrum that should be preferred for interstellar communications; and (3) not consistently concentrated on the regions of the sky that hold the highest likelihood for the emergence of extraterrestrial intelligence. The very nature of past searches provides a credible explanation for the null result to date. It is impossible to predict the specific technologies and communications methodologies likely to be adopted by extraterrestrial civilisations, particularly when one considers how much older and more technologically advanced than ourselves they may be. However, beginning with a single key assumption – that energy efficiency is a concern to those wishing to transmit signals across interstellar space – this work shows how the application of fundamental principles of astrophysics and information theory can lead to meaningful constraints on the discovery space for artificial interstellar signals. It is shown why the search for extraterrestrial intelligence should focus on intentionally transmitted wideband signals occupying the upper end of the microwave range of the radio spectrum - a region largely ignored by past searches. Furthermore, searches should concentrate on the inner Galaxy rather than our own solar neighbourhood. A new signal processing algorithm is introduced for the blind detection of wideband signals of a class that is attractive for interstellar communications, offering high detection sensitivity while making minimal assumptions about the precise signal format. The findings of this thesis suggest a range of new priorities and approaches to the search for extraterrestrial intelligence, aimed at increasing its chances of success. Declaration relating to disposition of project thesis/dissertation I hereby grant to the University of New South Wales or its agents the right to archive and to make available my thesis or dissertation in whole or in part in the University libraries in all forms of media, now or here after known, subject to the provisions of the Copyright Act 1968. I retain all property rights, such as patent rights. I also retain the right to use in future works (such as articles or books) all or part of this thesis or dissertation. I also authorise University Microfilms to use the 350 word abstract of my thesis in Dissertation Abstracts International (this is applicable to doctoral theses only). …………………………………………………………… ……………………………………..……………… ……….……………………...…….… Signature Witness Date The University recognises that there may be exceptional circumstances requiring restrictions on copying or conditions on use. Requests for restriction for a period of up to 2 years must be made in writing. Requests for a longer period of restriction may be considered in exceptional circumstances and require the approval of the Dean of Graduate Research. FOR OFFICE USE ONLY Date of completion of requirements for Award: ii COPYRIGHT STATEMENT ‘I hereby grant the University of New South Wales or its agents the right to archive and to make available my thesis or dissertation in whole or part in the University libraries in all forms of media, now or here after known, subject to the provisions of the Copyright Act 1968. I retain all proprietary rights, such as patent rights. I also retain the right to use in future works (such as articles or books) all or part of this thesis or dissertation. I also authorise University Microfilms to use the 350 word abstract of my thesis in Dissertation Abstract International (this is applicable to doctoral theses only). I have either used no substantial portions of copyright material in my thesis or I have obtained permission to use copyright material; where permission has not been granted I have applied/will apply for a partial restriction of the digital copy of my thesis or dissertation.' bwtmowin Date ……………………………………………..........1618117 ................. AUTHENTICITY STATEMENT ‘I certify that the Library deposit digital copy is a direct equivalent of the final officially approved version of my thesis. No emendation of content has occurred and if there are any minor variations in formatting, they are the result of the conversion to digital format.’ Signed …………………………………………..........hmtmrmn ................. Date ……………………………………………..........1618117 ................. Constraining the discovery space for artificial interstellar signals Originality Statement ‘I hereby declare that this submission is my own work and to the best of my knowledge it contains no materials previously published or written by another person, or substantial proportions of material which have been accepted for the award of any other degree or diploma at UNSW or any other educational institution, except where due acknowledgement is made in the thesis. Any contribution made to the research by others, with whom I have worked at UNSW or elsewhere, is explicitly acknowledged in the thesis. I also declare that the intellectual content of this thesis is the product of my own work, except to the extent that assistance from others in the project's design and conception or in style, presentation and linguistic expression is acknowledged.’ Signed …………………………………………….............. Date ……………………………………………….............. iii Constraining the discovery space for artificial interstellar signals Table of Contents Originality Statement .................................................................................................................... iii List of Abbreviations .................................................................................................................... vii Acknowledgements ..................................................................................................................... viii Publications and presentations arising from this work ............................................................... ix Chapter 1. Introduction .............................................................................................................. 1 1.1 Are there signals to find? .............................................................................................. 1 1.2 A new paradigm for SETI ............................................................................................... 3 1.3 Thesis scope and structure ........................................................................................... 7 Chapter 2. Artificial interstellar signals .................................................................................... 10 2.1 Eavesdropping versus intentional beacons ................................................................ 10 2.2 The narrowband assumption and its weaknesses ...................................................... 14 2.3 Isotropic versus directional beacons .......................................................................... 21 2.4 Wideband signalling for efficient communication of information ............................. 23 2.5 Discovery versus communications .............................................................................. 27 2.6 Challenges of wideband SETI ...................................................................................... 28 2.7 Blind detection ............................................................................................................ 31 2.8 Examples of wideband signal types suited to interstellar communications ............... 32 2.8.1 M-ary orthogonal modulation ............................................................................ 32 2.8.2 Spread-spectrum phase modulation .................................................................. 34 2.9 Data rates for interstellar communications ................................................................ 38 2.10 Detection methods for wideband SETI ....................................................................... 39 2.10.1 Matched filtering ................................................................................................ 40 2.10.2 Power spectral density ........................................................................................ 46 2.10.3 Energy detection ................................................................................................. 47 2.10.4 Statistical
Load more

Recommended publications
  • ASU Colloquium
    New Frontiers in Artifact SETI: Waste Heat, Alien Megastructures, and "Tabby's Star" Jason T Wright Penn State University SESE Colloquium Arizona State University October 4, 2017 Contact (Warner Bros.) What is SETI? • “The Search for Extraterrestrial Intelligence” • A field of study, like cosmology or planetary science • SETI Institute: • Research center in Mountain View, California • Astrobiology, astronomy, planetary science, radio SETI • Runs the Allen Telescope Array • Berkeley SETI Research Center: • Hosted by the UC Berkeley Astronomy Department • Mostly radio astronomy and exoplanet detection • Runs SETI@Home • Runs the $90M Breakthrough Listen Project Communication SETI The birth of Radio SETI 1960 — Cocconi & Morrison suggest interstellar communication via radio waves Allen Telescope Array Operated by the SETI Institute Green Bank Telescope Operated by the National Radio Astronomy Observatory Artifact SETI Dyson (1960) Energy-hungry civilizations might use a significant fraction of available starlight to power themselves Energy is never “used up”, it is just converted to a lower temperature If a civilization collects or generates energy, that energy must emerge at higher entropy (e.g. mid-infrared radiation) This approach is general: practically any energy use by a civilization should give a star (or galaxy) a MIR excess IRAS All-Sky map (1983) The discovery of infrared cirrus complicated Dyson sphere searches. Credit: NASA GSFC, LAMBDA Carrigan reported on the Fermilab Dyson Sphere search with IRAS: Lots of interesting red sources:
    [Show full text]
  • Interstellar Communication: the Case for Spread Spectrum
    Interstellar Communication: The Case for Spread Spectrum David G Messerschmitta aDepartment of Electrical Engineering and Computer Sciences, 253 Cory Hall, University of California, Berkeley, California 94720-1770, USA, [email protected], 1-925-465-5740 Abstract Spread spectrum, widely employed in modern digital wireless terrestrial radio systems, chooses a signal with a noise-like character and much higher bandwidth than necessary. This paper advocates spread spectrum modulation for interstellar communication, motivated by robust immunity to radio- frequency interference (RFI) of technological origin in the vicinity of the receiver while preserving full detection sensitivity in the presence of natural sources of noise. Receiver design for noise immunity alone provides no basis for choosing a signal with any specific character, therefore failing to reduce ambiguity. By adding RFI to noise immunity as a design objective, the conjunction of choice of signal (by the transmitter) together with optimum detection for noise immunity (in the receiver) leads through simple probabilistic argument to the conclusion that the signal should possess the statistical properties of a burst of white noise, and also have a large time-bandwidth product. Thus spread spectrum also provides an implicit coordination between transmitter and receiver by reducing the ambiguity as to the signal character. This strategy requires the receiver to guess the specific noise-like signal, and it is contended that this is feasible if an appropriate pseudorandom signal is generated algorithmically. For example, conceptually simple algorithms like the binary expansion of common irrational numbers like π are shown to be suitable. Due to its deliberately wider bandwidth, spread spectrum is more susceptible to dispersion and distortion in propagation through the interstellar medium, desirably reducing ambiguity in parameters like bandwidth and carrier frequency.
    [Show full text]
  • SETI SETI Stands for Search for Extraterrestrial Intelligence, and Usually Is Meant As an Acronym for Searches for Radio Commu
    SETI SETI stands for Search for Extraterrestrial Intelligence, and usually is meant as an acronym for searches for radio commu- nications from extraterrestrials which has been its backbone. It began with a seminal paper in 1959 by Giuseppe Cocconi and Philip Morrison in Nature suggesting that the best way to find extraterrestrial civilizations was to search in the radio near 1420 MHz (H spin-flip). The first SETI, project Ozma (1960, Frank Drake, originator of the Drake equation) used the 85- foot Green Bank, WV telescope; today SETI@home uses the 1000-foot Arecibo radio telescope in Puerto Rico. The Plane- tary Society has played an important role in supporting SETI, ever since the ban on Federal funding for it in 1982-83 and from 1992 to the present. Other projects have included Suit- case SETI, META, BETA, SERENDIP and META II. Thinking about SETI took a new turn in 1967 when Joce- lyn Bell and her advisor, Anthony Hewish, discovered pulsars, which they initially referred to, jokingly, as LGM (little green men). Another pioneer of SETI was Bernard Oliver, Vice Pres- ident of Hewlett Packard, who suggested in 1971 the cosmic waterhole hypothesis and emphasized the relative \quietness" of the radio spectrum between 1 and 1000 GHz. Project Ozma operated for about 3 months, devoting about 200 hours of observation to its two targets Tau Ceti and Epsilon Eridani. It scanned 7200 channels each with a bandwidth of 100 Hz, centered on 1420 MHz. By looking at adjacent frequencies, Doppler shifts caused by relative motions of our planets and Suns would be incorporated.
    [Show full text]
  • The Search for Extraterrestrial Intelligence
    THE SEARCH FOR EXTRATERRESTRIAL INTELLIGENCE Are we alone in the universe? Is the search for extraterrestrial intelligence a waste of resources or a genuine contribution to scientific research? And how should we communicate with other life-forms if we make contact? The search for extraterrestrial intelligence (SETI) has been given fresh impetus in recent years following developments in space science which go beyond speculation. The evidence that many stars are accompanied by planets; the detection of organic material in the circumstellar disks of which planets are created; and claims regarding microfossils on Martian meteorites have all led to many new empirical searches. Against the background of these dramatic new developments in science, The Search for Extraterrestrial Intelligence: a philosophical inquiry critically evaluates claims concerning the status of SETI as a genuine scientific research programme and examines the attempts to establish contact with other intelligent life-forms of the past thirty years. David Lamb also assesses competing theories on the origin of life on Earth, discoveries of ex-solar planets and proposals for space colonies as well as the technical and ethical issues bound up with them. Most importantly, he considers the benefits and drawbacks of communication with new life-forms: how we should communicate and whether we could. The Search for Extraterrestrial Intelligence is an important contribution to a field which until now has not been critically examined by philosophers. David Lamb argues that current searches should continue and that space exploration and SETI are essential aspects of the transformative nature of science. David Lamb is honorary Reader in Philosophy and Bioethics at the University of Birmingham.
    [Show full text]
  • Project Cyclops : a Design Study of a System for Detecting
    ^^^^m•i.j . --f'v.i^ "^y^-!^ A Design Study of a System for Detecting Extraterrestrial Intelligent Life '• >..-, i,C%' PREPARED UNDER STANFORD /NASA /AMES RESEARCH CENTER >J^1t> 1971 SUMMER FACULTY FELLOWSHIP PROGRAM IN ENGINEERING SYSTEMS DESIGr CR 114445 (Revised Edition 7/73) Available to the public rB' ^ A Design Study of a System for Detecting Extraterrestrial Intelligent Life PREPARED UNDER STANFORD/ NASA/AMES RESEARCH CENTER 1971 SUMMER FACULTY FELLOWSHIP PROGRAM IN ENGINEERING SYSTEMS DESIGN Further copies of this report may be obtained by writing to Dr. John Billingham NASA/ Ames Research Center, Code LT Moffett Field, California 94035 weixesunr colligc LWRART CYCLOPS PEOPLE Co-Directors: Bernard M. Oliver Stanford University (Summer appointment) John Billingham Ames Research Center, NASA System Design and Advisory Group: James Adams Stanford University Edwin L. Duckworth San Francisco City College Charles L. Seeger New Mexico State University George Swenson University of Illinois Antenna Structures Group: Lawrence S. Hill California State College L.A. John Minor New Mexico State University Ronald L. Sack University of Idaho Harvey B. Sharfstein San Jose State College Pennsylvania Alan 1. Soler University of Receiver Group: Washington Ward J. Helms University of William Hord Southern Illinois University Pierce Johnson University of Missouri C. ReedPredmore Rice University Transmission and Control Group: Marvin Siegel Michigan State University Jon A. Soper Michigan Technological University Henry J. Stalzer, Jr. Cooper Union Signal Processing Group: Jonnie B. Bednar University of Tulsa Douglas B. Brumm Michigan Technological University James H. Cook Cleveland State University Robert S. Dixon Ohio State University Johnson Luh Purdue University Francis Yu Wayne State University /./ la J C, /o ) •»• < .
    [Show full text]
  • Astrobiology and the Search for Life Beyond Earth in the Next Decade
    Astrobiology and the Search for Life Beyond Earth in the Next Decade Statement of Dr. Andrew Siemion Berkeley SETI Research Center, University of California, Berkeley ASTRON − Netherlands Institute for Radio Astronomy, Dwingeloo, Netherlands Radboud University, Nijmegen, Netherlands to the Committee on Science, Space and Technology United States House of Representatives 114th United States Congress September 29, 2015 Chairman Smith, Ranking Member Johnson and Members of the Committee, thank you for the opportunity to testify today. Overview Nearly 14 billion years ago, our universe was born from a swirling quantum soup, in a spectacular and dynamic event known as the \big bang." After several hundred million years, the first stars lit up the cosmos, and many hundreds of millions of years later, the remnants of countless stellar explosions coalesced into the first planetary systems. Somehow, through a process still not understood, the laws of physics guiding the unfolding of our universe gave rise to self-replicating organisms − life. Yet more perplexing, this life eventually evolved a capacity to know its universe, to study it, and to question its own existence. Did this happen many times? If it did, how? If it didn't, why? SETI (Search for ExtraTerrestrial Intelligence) experiments seek to determine the dis- tribution of advanced life in the universe through detecting the presence of technology, usually by searching for electromagnetic emission from communication technology, but also by searching for evidence of large scale energy usage or interstellar propulsion. Technology is thus used as a proxy for intelligence − if an advanced technology exists, so to does the ad- vanced life that created it.
    [Show full text]
  • The Radio Search for Technosignatures in the Decade 2020–2030
    Astro2020 Science White Paper The radio search for technosignatures in the decade 2020–2030 Background photo: central region of the Galaxy by Yuri Beletsky, Carnegie Las Campanas Observatory Thematic Area: Planetary Systems Principal Author: Name: Jean-Luc Margot Institution: University of California, Los Angeles Email: [email protected] Phone: 310.206.8345 Co-authors: Steve Croft (University of California, Berkeley), T. Joseph W. Lazio (Jet Propulsion Laboratory), Jill Tarter (SETI Institute), Eric J. Korpela (University of California, Berkeley) March 11, 2019 1 Scientific context Are we alone in the universe? This question is one of the most profound scientific questions of our time. All life on Earth is related to a common ancestor, and the discovery of other forms of life will revolutionize our understanding of living systems. On a more philosophical level, it will transform our perception of humanity’s place in the cosmos. Observations with the NASA Kepler telescope have shown that there are billions of habitable worlds in our Galaxy [e.g., Borucki, 2016]. The profusion of planets, coupled with the abundance of life’s building blocks in the universe, suggests that life itself may be abundant. Currently, the two primary strategies for the search for life in the universe are (1) searching for biosignatures in the Solar System or around nearby stars and (2) searching for technosignatures emitted from sources in the Galaxy and beyond [e.g., National Academies of Sciences, Engineer- ing, and Medicine, 2018]. Given our present knowledge of astrobiology, there is no compelling reason to believe that one strategy is more likely to succeed than the other.
    [Show full text]
  • Biosignatures Search in Habitable Planets
    galaxies Review Biosignatures Search in Habitable Planets Riccardo Claudi 1,* and Eleonora Alei 1,2 1 INAF-Astronomical Observatory of Padova, Vicolo Osservatorio, 5, 35122 Padova, Italy 2 Physics and Astronomy Department, Padova University, 35131 Padova, Italy * Correspondence: [email protected] Received: 2 August 2019; Accepted: 25 September 2019; Published: 29 September 2019 Abstract: The search for life has had a new enthusiastic restart in the last two decades thanks to the large number of new worlds discovered. The about 4100 exoplanets found so far, show a large diversity of planets, from hot giants to rocky planets orbiting small and cold stars. Most of them are very different from those of the Solar System and one of the striking case is that of the super-Earths, rocky planets with masses ranging between 1 and 10 M⊕ with dimensions up to twice those of Earth. In the right environment, these planets could be the cradle of alien life that could modify the chemical composition of their atmospheres. So, the search for life signatures requires as the first step the knowledge of planet atmospheres, the main objective of future exoplanetary space explorations. Indeed, the quest for the determination of the chemical composition of those planetary atmospheres rises also more general interest than that given by the mere directory of the atmospheric compounds. It opens out to the more general speculation on what such detection might tell us about the presence of life on those planets. As, for now, we have only one example of life in the universe, we are bound to study terrestrial organisms to assess possibilities of life on other planets and guide our search for possible extinct or extant life on other planetary bodies.
    [Show full text]
  • Searching for Extraterrestrial Intelligence
    THE FRONTIERS COLLEctION THE FRONTIERS COLLEctION Series Editors: A.C. Elitzur L. Mersini-Houghton M. Schlosshauer M.P. Silverman J. Tuszynski R. Vaas H.D. Zeh The books in this collection are devoted to challenging and open problems at the forefront of modern science, including related philosophical debates. In contrast to typical research monographs, however, they strive to present their topics in a manner accessible also to scientifically literate non-specialists wishing to gain insight into the deeper implications and fascinating questions involved. Taken as a whole, the series reflects the need for a fundamental and interdisciplinary approach to modern science. Furthermore, it is intended to encourage active scientists in all areas to ponder over important and perhaps controversial issues beyond their own speciality. Extending from quantum physics and relativity to entropy, consciousness and complex systems – the Frontiers Collection will inspire readers to push back the frontiers of their own knowledge. Other Recent Titles Weak Links Stabilizers of Complex Systems from Proteins to Social Networks By P. Csermely The Biological Evolution of Religious Mind and Behaviour Edited by E. Voland and W. Schiefenhövel Particle Metaphysics A Critical Account of Subatomic Reality By B. Falkenburg The Physical Basis of the Direction of Time By H.D. Zeh Mindful Universe Quantum Mechanics and the Participating Observer By H. Stapp Decoherence and the Quantum-To-Classical Transition By M. Schlosshauer The Nonlinear Universe Chaos, Emergence, Life By A. Scott Symmetry Rules How Science and Nature are Founded on Symmetry By J. Rosen Quantum Superposition Counterintuitive Consequences of Coherence, Entanglement, and Interference By M.P.
    [Show full text]
  • Interstellar Communication. Iii. Optimal Frequency to Maximize Data Rate
    Draft version November 17, 2017 INTERSTELLAR COMMUNICATION. III. OPTIMAL FREQUENCY TO MAXIMIZE DATA RATE Michael Hippke1 and Duncan H. Forgan2, 3 1Sonneberg Observatory, Sternwartestr. 32, 96515 Sonneberg, Germany 2SUPA, School of Physics & Astronomy, University of St Andrews, North Haugh, St Andrews, Scotland, KY16 9SS, UK 3St Andrews Centre for Exoplanet Science, University of St Andrews, UK ABSTRACT The optimal frequency for interstellar communication, using \Earth 2017" technology, was derived in papers I and II of this series (Hippke 2017a,b). The framework included models for the loss of photons from diffraction (free space), interstellar extinction, and atmospheric transmission. A major limit of current technology is the focusing of wavelengths λ < 300 nm (UV). When this technological constraint is dropped, a physical bound is found at λ ≈ 1 nm (E ≈ keV) for distances out to kpc. While shorter wavelengths may produce tighter beams and thus higher data rates, the physical limit comes from surface roughness of focusing devices at the atomic level. This limit can be surpassed by beam-forming with electromagnetic fields, e.g. using a free electron laser, but such methods are not energetically competitive. Current lasers are not yet cost efficient at nm wavelengths, with a gap of two orders of magnitude, but future technological progress may converge on the physical optimum. We recommend expanding SETI efforts towards targeted (at us) monochromatic (or narrow band) X-ray emission at 0.5-2 keV energies. 1. INTRODUCTION believed to originate from intelligent beings on Mars. The idea to communicate with Extraterrestrial Intel- In the optical, William Pickering(1909) suggested to ligence was born in the 19th century.
    [Show full text]
  • Radio Astronomy
    Edition of 2013 HANDBOOK ON RADIO ASTRONOMY International Telecommunication Union Sales and Marketing Division Place des Nations *38650* CH-1211 Geneva 20 Switzerland Fax: +41 22 730 5194 Printed in Switzerland Tel.: +41 22 730 6141 Geneva, 2013 E-mail: [email protected] ISBN: 978-92-61-14481-4 Edition of 2013 Web: www.itu.int/publications Photo credit: ATCA David Smyth HANDBOOK ON RADIO ASTRONOMY Radiocommunication Bureau Handbook on Radio Astronomy Third Edition EDITION OF 2013 RADIOCOMMUNICATION BUREAU Cover photo: Six identical 22-m antennas make up CSIRO's Australia Telescope Compact Array, an earth-rotation synthesis telescope located at the Paul Wild Observatory. Credit: David Smyth. ITU 2013 All rights reserved. No part of this publication may be reproduced, by any means whatsoever, without the prior written permission of ITU. - iii - Introduction to the third edition by the Chairman of ITU-R Working Party 7D (Radio Astronomy) It is an honour and privilege to present the third edition of the Handbook – Radio Astronomy, and I do so with great pleasure. The Handbook is not intended as a source book on radio astronomy, but is concerned principally with those aspects of radio astronomy that are relevant to frequency coordination, that is, the management of radio spectrum usage in order to minimize interference between radiocommunication services. Radio astronomy does not involve the transmission of radiowaves in the frequency bands allocated for its operation, and cannot cause harmful interference to other services. On the other hand, the received cosmic signals are usually extremely weak, and transmissions of other services can interfere with such signals.
    [Show full text]
  • Astronomy Beat
    ASTRONOMY BEAT ASTRONOMY BEAT /VNCFSt"QSJM XXXBTUSPTPDJFUZPSH 1VCMJTIFS"TUSPOPNJDBM4PDJFUZPGUIF1BDJöD &EJUPS"OESFX'SBLOPJ ª "TUSPOPNJDBM 4PDJFUZ PG UIF 1BDJöD %FTJHOFS-FTMJF1SPVEöU "TIUPO"WFOVF 4BO'SBODJTDP $" The Origin of the Drake Equation Frank Drake Dava Sobel Editor’s Introduction Most beginning classes in astronomy introduce their students to the Drake Equation, a way of summarizing our knowledge about the chances that there is intelli- ASTRONOMYgent life among the stars with which we humans might BEAT communicate. But how and why did this summary for- mula get put together? In this adaptation from a book he wrote some years ago with acclaimed science writer Dava Sobel, astronomer and former ASP President Frank Drake tells us the story behind one of the most famous teaching aids in astronomy. ore than a year a!er I was done with Proj- 'SBOL%SBLFXJUIUIF%SBLF&RVBUJPO 4FUI4IPTUBL 4&5**OTUJUVUF ect Ozma, the "rst experiment to search for radio signals from extraterrestrial civiliza- Mtions, I got a call one summer day in 1961 from a man to be invited. I had never met. His name was J. Peter Pearman, and Right then, having only just met over the telephone, we he was a sta# o$cer on the Space Science Board of the immediately began planning the date and other details. National Academy of Science… He’d followed Project We put our heads together to name every scientist we Ozma throughout, and had since been trying to build knew who was even thinking about searching for ex- support in the government for the possibility of dis- traterrestrial life in 1961.
    [Show full text]