A rigorous and scientific analysis of the myriad possibilities of life beyond our planet.
“Are we alone in the universe?” This tantalizing question has captivated humanity over millennia, but seldom has it been approached rigorously. Today the search for signatures of extraterrestrial life and intelligence has become a rapidly advancing scientific endeavour. Missions to Mars, Europa, and Titan seek evidence of life. Laboratory experiments have made great strides in creating synthetic life, deepening our understanding of conditions that give rise to living entities. And on the horizon are sophisticated telescopes to detect and characterize exoplanets most likely to harbour life.
Life in the Cosmos offers a thorough overview of the burgeoning field of astrobiology, including the salient methods and paradigms involved in the search for extraterrestrial life and intelligence. Manasvi Lingam and Abraham Loeb tackle three areas of interest in hunting for life “out there”: first, the pathways by which life originates and evolves; second, planetary and stellar factors that affect the habitability of worlds, with an eye on the biomarkers that may reveal the presence of microbial life; and finally, the detection of technological signals that could be indicative of intelligence. Drawing on empirical data from observations and experiments, as well as the latest theoretical and computational developments, the authors make a compelling scientific case for the search for life beyond what we can currently see.
Meticulous and comprehensive, Life in the Cosmos is a master class from top researchers in astrobiology, suggesting that the answer to our age-old question is closer than ever before.
1. Some Intrinsic Properties of Life
1.1. Defining life: Does it matter?
1.2. The requirements for life
1.3. The Anna Karenina principle
I. The Origin and Evolution of Life on Earth
2. The Pathways to the Origin of Life on Earth
2.1. When did life originate on Earth?
2.2. The basic building blocks of life
2.3. Synthesis of the basic building blocks of life
2.4. The polymerization of monomers
2.5. The RNA world
2.6. Did metabolism arise first?
2.7. What are the plausible sites for abiogenesis?
2.8. Mathematical models relating to the origin of life
3. The Evolutionary History of Life on Earth
3.1. The origin of life
3.2. The diversification of bacteria and archaea
3.3. Oxygenic photosynthesis
3.4. The rise of oyxgen and the Great Oxygenation Event
3.6. Complex multicellularity
3.7. Intelligence in animals
3.8. Technological intelligence
3.9. Paradigms for major evolutionary events
3.10. The critical steps model
II. Aspects of Extraterrestrial Biospheres
4. Habitability: Stellar Factors
4.1. The habitable zone and its extensions
4.2. Stellar winds
4.3. Stellar electromagnetic radiation
4.4. Stellar flares and associated space weather phenomena
5. Habitability: Planetary Factors
5.1. The myriad roles of temperature
5.2. Plate tectonics and habitability
5.3. Tidal locking and its consequences
5.4. Atmospheric composition
5.5. The extent of landmasses and oceans on the surface
5.6. The distribution of landmasses and oceans
5.7. Life in the atmosphere
6. The Quest for Biosignatures
6.1. Transiting planets
6.2. Non-transiting planets
6.3. Alternative observational constraints on habitability
6.4. Gaseous biosignatures
6.5. Surface biosignatures
6.6. Temporal biosignatures
6.7. False positives versus real biosignatures
6.8. Assessing the plausibility of life detection
7. Life in Subsurface Oceans
7.1. Worlds with subsurface oceans within our solar system
7.2. Temperature profiles of the ice envelopes
7.3. The habitats for subsurface ocean worlds
7.4. The routes to abiogenesis on subsurface ocean worlds
7.5. Ecosystems in planets with subsurface oceans
7.6. Bioessential elements and subsurface ocean worlds
7.7. Evolutionary trajectories on subsurface ocean worlds
7.8. Number of subsurface ocean worlds and the implications for detection
III. Aspects of Extraterrestrial Technospheres
8. The Drake Equation and Fermi’s Paradox
8.1. The Drake equation
8.2. The great silence: Where is everybody?
9. The Quest for Technosignatures
9.1. Radio technosignatures
9.2. Optical and infrared technosignatures
9.3. Modality of interstellar signaling
9.4. On the classification of technological agents
9.5. Artifact technosignatures
9.6. The relative prospects for detecting ETIs
10. The Propagation of Life in the Universe
10.1. History and principles of panspermia
10.2. Interplanetary and interstellar panspermia
10.3. Seeking potential signatures of panspermia
10.4. Interstellar travel via rockets
10.5. Interstellar travel without onboard fuel
Epilogue: Sic Itur Ad Astra
Manasvi Lingam is Assistant Professor of Astrobiology at the Florida Institute of Technology, an affiliate of the Institute for Theory and Computation at Harvard University, and a member of the American Physical Society.
Abraham Loeb is Frank B. Baird, Jr., Professor of Science at Harvard University. He is Founding Director of Harvard’s Black Hole Initiative, chair of the Board on Physics and Astronomy of the National Academies, and a fellow of the American Academy of Arts and Sciences.
"The new go-to for astrobiology. Life in the Cosmos is a quantitative and encyclopedic tour de force for all topics related to the origin of life on Earth and life's existence beyond."
– Sara Seager, author of The Smallest Lights in the Universe
"An instant classic. Lingam and Loeb's brilliant Life in the Cosmos is a momentous scientific achievement. To anyone looking to dig deep into the exciting prospect of discovering extraterrestrial life, I say: Make space on your bookshelf."
– Michael J. Russell, University of Turin
"Are we alone in the universe? Lingam and Loeb provide expert guidance to the many dimensions of this fundamental question – and, just maybe, how to answer it."
– Andrew H. Knoll, author of A Brief History of Earth: Four Billion Years in Eight Chapters
"A book of sweeping vision. Lingam and Loeb offer detailed and insightful analysis of the challenges we face as we investigate the universal distribution of this unusual material we call life. A helpful and fascinating read."
– Charles Cockell, author of Astrobiology: Understanding Life in the Universe
"A remarkable and modern survey of how to search for life in the universe, from two of the boldest, most innovative thinkers in the field today. Impressively detailed, this book takes into account what we know about life on Earth to consider what we don't know about life elsewhere."
– Jason Wright, Director, Penn State Extraterrestrial Intelligence Center
"This book discusses everything you ever wanted to know about life in the cosmos. Lingam and Loeb are the best guides for this truly breathtaking journey, providing masterful and comprehensive answers for everyone, from the scholar to the amateur stargazer."
– Dimitar Sasselov, author of The Life of Super-Earths: How the Hunt for Alien Worlds and Artificial Cells Will Revolutionize Life on Our Planet