Table Of ContentTechnosignatures for Detecting
Intelligent Life in Our Universe
Scrivener Publishing
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Beverly, MA 01915-6106
Astrobiology Perspectives on Life of the Universe
Series Editors: Richard Gordon and Joseph Seckbach
In his 1687 book Principia, Isaac Newton showed how a body launched atop a tall mountain parallel to
the ground would circle the Earth. Many of us are old enough to have witnessed the realization of this
dream in the launch of Sputnik in 1957. Since then our ability to enter, view and understand the Universe
has increased dramatically. A great race is on to discover real extraterrestrial life, and to understand our
origins, whether on Earth or elsewhere. We take part of the title for this new series of books from the
pioneering thoughts of Svante Arrhenius, who reviewed this quest in his 1909 book The Life of the
Universe as Conceived by Man from the Earliest Ages to the Present Time. The volumes in Astrobiology
Perspectives on Life of the Universe will each delve into an aspect of this adventure, with chapters by
those who are involved in it, as well as careful observers and assessors of our progress. Guest editors are
invited from time to time, and all chapters are peer-reviewed.
Publishers at Scrivener
Martin Scrivener ([email protected])
Phillip Carmical ([email protected])
Technosignatures for Detecting
Intelligent Life in Our Universe
A Research Companion
Edited by
Anamaria Berea
Dept. of Data and Computational Sciences, George Mason University,
Virginia, USA
This edition first published 2022 by John Wiley & Sons, Inc., 111 River Street, Hoboken, NJ 07030, USA
and Scrivener Publishing LLC, 100 Cummings Center, Suite 541J, Beverly, MA 01915, USA
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Library of Congress Cataloging-in-Publication Data
ISBN 978-1-119-64040-0
Cover image: https://commons.wikimedia.org/wiki/File:Dyson_Sphere_Render.png
Cover design by Russell Richardson
Set in size of 11pt and Minion Pro by Manila Typesetting Company, Makati, Philippines
Printed in the USA
10 9 8 7 6 5 4 3 2 1
Contents
Preface ix
1 Historical Perspectives: How the Search for Technosignatures
Grew Out of the Cold War 1
Rebecca Charbonneau
1.1 Introduction 1
1.2 The Extraterrestrial Life Debate Gets Technical 3
1.3 Finding the 21-cm Hydrogen Line 7
1.4 The Role of the Space Race in Early CETI 10
1.5 Same Planet, Different Civilizations 13
1.6 Making Intelligent Life in the Universe 19
1.7 Conclusion: Returning to L 23
References 25
2 Reading the Cosmos: What Our Science Tells Us About
the Science of Another World 33
Carl L. DeVito
2.1 Introduction 33
2.2 The Why and How of Interstellar Communication 34
2.3 An Early Language 36
2.4 A Language Based on Science 36
2.5 Our Senses, Our Perceptions and Our Science 38
2.5.1 Motion 38
2.5.2 Space “in the small” 39
2.5.3 Time 39
2.5.4 Space “in the large” 40
2.5.5 Mathematics 42
2.6 Conclusion 44
References 45
v
vi Contents
3 The Impact of Discovering the First Technosignature 47
Ross Davis, Kevin Schillo and Lucianne Walkowicz
3.1 Introduction 48
3.2 Cultural Impact Based on Analogous Historical Events 48
3.3 Modeling the Impact Based on the Discovery’s Diffusion
into Society 49
3.4 Multimodal Diffusion into Knowledge Systems
of Complex Publics 52
References 55
4 Searching for Extraterrestrial Intelligence by Locating
Potential ET Communication Networks in Space 57
Ross Davis
4.1 Introduction 58
4.2 Concepts 60
4.3 Case Study 63
4.4 Conclusions 64
Acknowledgements 65
References 66
5 Habitable Mini-Earths with Black Hole Cores 69
Branislav Vukotić and Richard Gordon
5.1 Introduction 70
5.2 Surface Comfort 71
5.3 Concept and Design 72
5.4 Surface Conditions and Size 72
5.5 Black Hole Core 75
5.6 Mass Boosting and Terraformation 76
5.7 Technosignatures 76
5.8 Conclusion 77
Acknowledgement 78
References 78
6 Technosignatures in Time-Series Photometry 85
Hector Socas-Navarro, Shauna Sallmen, Eric Korpela
and Daniel Angerhausen
6.1 Introduction 85
6.2 Types of Technosignatures 87
6.2.1 Dyson Spheres 87
6.2.2 Transit Beacons 88
6.2.3 Orbital Mirrors 88
6.2.4 Lagrange-Point Starshades 89
Contents vii
6.2.5 Geostationary Artifacts 90
6.2.6 Laser Broadcasting and Planetary Cloaking 93
6.2.7 Non-Keplerian Orbits 93
6.3 Axis of Merit Discussion for These Technosignatures 93
6.4 Methods 97
6.4.1 Detectability of Time-Series Technosignatures 98
References 99
7 Post-Detection Message Analysis and Comprehension 103
Brian S. McConnell
7.1 Categorizing an ET Signal 103
7.1.1 Megastructures 103
7.1.2 Beamed Power and Propulsion Signals 104
7.1.3 Intercepted Communication 104
7.1.4 Intentional Communication 104
7.2 The Interstellar Communication Relay 106
7.3 The Processing Pipeline and Participants 106
7.4 Demodulation 107
7.4.1 Pulse Width Modulation 107
7.4.2 Pulse Interval Modulation 107
7.5 Combining Pulse Width and Pulse Interval Modulation 108
7.5.1 Wavelength Multiplexing 108
7.5.2 Information Carrying Capacity 108
7.6 Data Extraction 109
7.6.1 Transcription 109
7.6.2 Structural Analysis 110
7.6.3 Segmentation and Extraction 110
7.6.4 Data Types 110
7.6.5 Communicating Observables vs. Qualia 111
7.6.6 Images 111
7.6.7 Time Domain Signals 112
7.6.8 Algorithms (Computer Programs) 114
7.6.9 Solve For X Patterns 114
7.6.10 Memory 115
7.6.11 Modularity and Reuse 115
7.6.12 Symbolic Communication Systems and Artificial
Languages 117
7.6.13 Genomic Information 118
7.6.14 Other Data Types 118
7.7 Classifying ETI Communication 119
7.7.1 Static/One Way Communication 119
viii Contents
7.7.2 Algorithmic Systems 121
7.7.3 Statically Defined Programs 121
7.7.4 Data-Driven Programs 121
7.7.5 Machine Learning/Narrow AI 122
7.7.6 Adaptive/Self-Learning Systems 122
7.8 Risks of Contact 123
7.8.1 Internal (Human Originated) Risks 123
7.8.1.1 Interstate Competition and Interference 123
7.8.2 Misinformation 123
7.8.3 Societal Reaction 123
7.8.4 External Risks 124
7.8.5 Algorithms 124
7.8.5.1 Malware 124
7.8.6 Artificial Intelligence 124
7.8.7 Genetic Information 124
7.8.8 Unknown Unknowns 125
References and Recommended Reading 125
8 Statistical Issues in the Search for Technosignatures 127
Amedeo Balbi and Claudio Grimaldi
8.1 Introduction 127
8.2 General Issues 130
8.3 Emission Processes 134
8.3.1 Drake’s N 135
D
8.3.2 Average Number of Emission Processes at Earth 136
8.4 Bayesian Inference from Non-Detection
and Detection 139
References 143
9 Economics and Technosignatures: New Connections 149
Anamaria Berea
9.1 The Different Faces of Economics 149
9.2 Economics in the Context of NASA Astrobiology
Roadmap and the Drake Equation 152
9.3 Economics in the Context of Biosignatures vs.
Technosignatures Research 153
9.4 Economic Methodology and Epistemology
into Astrobiology 155
References 156
Index 161
Preface
Technosignature is a term that encompasses the idea of searching for intel-
ligent, technological signatures of civilizations other than ours in the uni-
verse. A term that would probably be more familiar to the larger audience
would be SETI (search for extraterrestrial intelligence). Technosignatures
are the technological equivalent of biosignatures and a subset of biosigna-
tures, which represent evidence of alien life, whether it is intelligent or not.
They represent any signals that can be collected from the universe, such as
radio wavelengths, optical signals, and many more, that can be potential
candidates as signals emitted intentionally from another part of the uni-
verse that is not Earth.
This book—Technosignatures for Detecting Intelligent Life in Our
Universe: A Research Companion—represents a collection of works by a
wide diversity of researchers who have been in this field for a long time.
While there have been several books written on the subject in the past, this
is the newest research that we have to date in the field, and it by no means
represents all aspects of technosignatures research. But this book does give
us a good lens into the current state-of-the-art in the field. At the same
time, it spreads across a wide range of other fields that are tangential or are
used for SETI— from history and economics to communication, photom-
etry, statistics, data science, astrobiology, exoplanetary science, and many
more.
Some of the most important debates, when searching for life beyond our
planet, have been around the definitions of life and intelligence. While we
don’t have very accurate or universally agreed upon definitions for either
of these monumentally important concepts, we can recognize, in general,
what is life is and what intelligence is, especially on our planet. And, in
general, we assume there is no intelligence without life, as we also consider
artificial intelligence to be an extension and a byproduct of intelligent bio-
logical life. In fact, if biosignatures are signatures of life, in general, tech-
nosignatures are signatures of intelligent life, whether this life is biological,
artificial, or even extinct. There are many voices in the community that are
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