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Alone but Not Lonely: Exploring for Extraterrestrial Life
Humans have always been fascinated by the possibility of extraterrestrial life, often wondering if we are alone in the universe. Drawing on nearly fifty years as a leader in planetary exploration, Louis Friedman brings into focus the subject of extraterrestrial life, separating knowledge from conjecture, fact from fiction, to draw scientific and technical conclusions that answer this enduring question.
Friedman argues that intelligent life is probably rare in the universe (maybe even uniquely on Earth) but that simple life is likely abundant on millions or billions of planets waiting now to be discovered. He asserts that studying and searching for extraterrestrial life cannot be done by interstellar probes—due to the vastness of space and the comparative brevity of human lifespans—but it can be done remotely by a new technique involving the solar gravity lens that can magnify exoplanets by tens of billions. This technique will allow humankind to explore exoplanets and open up an exciting new field of comparative astrobiology.
Wide-ranging in scope, this book discusses the history of searching for extraterrestrial life, the scientific evidence thereof, and finally his own conclusions on what’s next. Included in the book are three an explanation of interstellar messaging, a reprint of a debate between Carl Sagan and Ernst Mayr on extraterrestrial intelligence, and an opinion essay on the search for extraterrestrial intelligence.
Friedman argues that intelligent life is probably rare in the universe (maybe even uniquely on Earth) but that simple life is likely abundant on millions or billions of planets waiting now to be discovered. He asserts that studying and searching for extraterrestrial life cannot be done by interstellar probes—due to the vastness of space and the comparative brevity of human lifespans—but it can be done remotely by a new technique involving the solar gravity lens that can magnify exoplanets by tens of billions. This technique will allow humankind to explore exoplanets and open up an exciting new field of comparative astrobiology.
Wide-ranging in scope, this book discusses the history of searching for extraterrestrial life, the scientific evidence thereof, and finally his own conclusions on what’s next. Included in the book are three an explanation of interstellar messaging, a reprint of a debate between Carl Sagan and Ernst Mayr on extraterrestrial intelligence, and an opinion essay on the search for extraterrestrial intelligence.
162 pages, Paperback
Published September 19, 2023
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September 12, 2023
The eternal question - Are We Alone?
In his interesting new book "Alone But Not Lonely," author Louis Friedman provides a comprehensive examination of humanity's ageless search for life beyond our planet. As I discovered this pre-release copy just ahead of its September publication, no Goodreads reviews yet exist. Given the fascinating and informative nature of the book, I try to write a long review.
The Search for Life Beyond Earth
For all of human history, we have wondered if life exists on other worlds beyond our own. This captivating question has permeated religion, philosophy, science and popular culture. In his book "Alone But Not Lonely: Exploring for Extraterrestrial Life," Dr. Louis Friedman provides a comprehensive overview of humanity's age-old search for life beyond Earth, assessing the possibility and likelihood of finding extraterrestrial intelligence and simpler alien lifeforms.
Early Speculation on Alien Life
Friedman begins by tracing the history of speculation about extraterrestrial life back to ancient Greek philosophers like Democritus and Lucretius, who supported the idea of inhabited alien worlds. He notes that for centuries, religion both opposed and supported the notion of alien life, depending on the doctrine.
The invention of the telescope and the science of astronomy moved the debate into the realm of science, though it remained speculative. The discovery in the 20th century that the galaxy contains billions of stars with planets led more scientists to conclude that life must exist somewhere out there.
This helped spur modern organized searches for extraterrestrial intelligence (ETI) using radio telescopes, which Friedman details in the book. However, these searches, now decades long, have still not yielded any definitive evidence of alien civilizations attempting to communicate across interstellar distances.
The Definition and Rarity of Intelligence
Friedman provides his own definition of intelligence as involving both scientific understanding of the environment and technological ability to communicate that understanding. He argues that by this definition, humans remain the only known intelligent species, despite some claims of intelligence in species like dolphins or chimpanzees on Earth.
He gives an overview of the various searches for ETI conducted over the past 50 years by scanning radio frequencies, which have found no clear signals that can be attributed to alien civilizations. Analysis of the results suggests that alien civilizations advanced enough to deliberately broadcast signals strong enough for us to detect are likely extremely rare or nonexistent in our galaxy.
Friedman argues that intelligence, technology and civilization may simply be an evolutionary accident unique to humans, rather than inevitabilities of evolution.
Possibilities for the Lack of Discovered Alien Civilizations
Given the size and age of the universe, the lack of any evidence for intelligent alien civilizations is perplexing. Friedman discusses various possible explanations that have been offered.
First, intelligent life may be far rarer than we imagine. Second, alien civilizations may tend to be short-lived for a variety of reasons, going extinct before they can expand significantly into the galaxy. Third, intelligence may not actually provide an evolutionary advantage, and could even be a liability that leads to short lifespans.
With Earth as the only current data point, the issue remains open. Friedman argues that the absence of any hints of intelligence beyond Earth, despite extensive searching, indicates it is likely extremely rare or nonexistent elsewhere in our galaxy.
Possibilities for Basic Alien Life
While intelligence may be scarce, Friedman argues that simpler extraterrestrial life is potentially abundant in the universe. Life arose very quickly on Earth after its formation, suggesting the origin of life may be commonplace on habitable worlds.
Ingredients for life like water and complex organic molecules are widespread throughout the galaxy. The thousands of exoplanets discovered in recent decades include many potentially habitable worlds, where life could exist.
Friedman gives an overview of our own solar system, noting several "ocean world" moons like Europa and Enceladus that may harbor life in warm underground oceans. He argues that while intelligence appears to be extremely rare, basic microbial alien life could be ubiquitous in the cosmos based on what we know so far.
The Limits of Interstellar Travel
Given the possibilities for life within our galaxy, can we travel to and explore potentially habitable exoplanets directly? Unfortunately, Friedman argues, practical interstellar travel is likely impossible. The distances between stars are simply too vast and spacecraft speeds too slow using any currently known means of propulsion.
While theoretical concepts have been proposed, none are remotely practical given the constraints of physics, engineering and cost. Even a voyage to merely the nearest stars would take tens of thousands of years.
More interesting habitable exoplanet destinations are hundreds or thousands of light years away. Alien worlds will have to be explored remotely through telescopes and probes rather than direct visitation.
Using the Sun as a Gravitational Lens
While we cannot travel to exoplanets, Friedman explains that there is a way to use our own sun to observe them at magnifications allowing surface study. Einstein's theory showed gravity bends the path of light rays.
This lensing effect means the Sun can magnify light from a distant exoplanet by a factor of 10 billion. By positioning a telescope at the focal point of this "solar gravitational lens," direct imaging of exoplanets may be possible even over interstellar distances.
This focal line begins at approximately 550 AU from the Sun, in the outer solar system. Reaching this region requires speeds of 35 AU per year, achievable with advanced solar sails on small probes.
A Series of Missions to the Stars
Rather than a single ambitious interstellar probe, Friedman advocates for a series of incremental missions, each pushing farther into the solar system and interstellar medium.
Developing advanced solar sails and testing them on probes to objects like Kuiper Belt objects and interstellar comets will enable eventual capability to reach the solar gravitational lensing focus point.
In concert with improving exoplanet imaging and mapping techniques from Earth and space telescopes, this could allow detailed observations of potentially habitable exoplanets to begin in the 2040s. Multiple small probes using solar gravitational lensing could survey several promising exoplanets simultaneously.
The Dawn of Comparative Astrobiology
What might we find in these direct observations of multiple alien worlds? Detailed imaging could provide clues about extraterrestrial life and biosignatures.
Friedman proposes that a new field of "comparative astrobiology" may emerge. With data from diverse exoplanets, scientists can study how life arises and evolves in different environments. This can provide key insights about the origins and prevalence of life in the cosmos, and help answer fundamental questions about our own existence and evolution.
Even if no technological alien civilizations are found, the study of multiple exoplanets potentially harboring microbial life will revolutionize our understanding of biology.
Alone But Not Lonely
Given the lack of any signals from or evidence for intelligent aliens, Friedman argues that humanity likely stands alone as the sole technological civilization in the Milky Way galaxy, if not the universe.
But while we may be alone, detailed exploration of other worlds teeming with life will prevent us from ever being lonely. Friedman ends on an optimistic and exciting note, envisioning a future where swarms of solar sail probes virtually visit distant exoplanets and beam home detailed data to build immersive 3D models.
He argues this will provide endless frontiers for exploration and discovery for centuries to come, as we uncover deeper insights about life, intelligence and our own existence. Even if we find no alien equivalents, observing myriad new forms of extraterrestrial life will bring us closer to understanding ourselves.
In his interesting new book "Alone But Not Lonely," author Louis Friedman provides a comprehensive examination of humanity's ageless search for life beyond our planet. As I discovered this pre-release copy just ahead of its September publication, no Goodreads reviews yet exist. Given the fascinating and informative nature of the book, I try to write a long review.
The Search for Life Beyond Earth
For all of human history, we have wondered if life exists on other worlds beyond our own. This captivating question has permeated religion, philosophy, science and popular culture. In his book "Alone But Not Lonely: Exploring for Extraterrestrial Life," Dr. Louis Friedman provides a comprehensive overview of humanity's age-old search for life beyond Earth, assessing the possibility and likelihood of finding extraterrestrial intelligence and simpler alien lifeforms.
Early Speculation on Alien Life
Friedman begins by tracing the history of speculation about extraterrestrial life back to ancient Greek philosophers like Democritus and Lucretius, who supported the idea of inhabited alien worlds. He notes that for centuries, religion both opposed and supported the notion of alien life, depending on the doctrine.
The invention of the telescope and the science of astronomy moved the debate into the realm of science, though it remained speculative. The discovery in the 20th century that the galaxy contains billions of stars with planets led more scientists to conclude that life must exist somewhere out there.
This helped spur modern organized searches for extraterrestrial intelligence (ETI) using radio telescopes, which Friedman details in the book. However, these searches, now decades long, have still not yielded any definitive evidence of alien civilizations attempting to communicate across interstellar distances.
The Definition and Rarity of Intelligence
Friedman provides his own definition of intelligence as involving both scientific understanding of the environment and technological ability to communicate that understanding. He argues that by this definition, humans remain the only known intelligent species, despite some claims of intelligence in species like dolphins or chimpanzees on Earth.
He gives an overview of the various searches for ETI conducted over the past 50 years by scanning radio frequencies, which have found no clear signals that can be attributed to alien civilizations. Analysis of the results suggests that alien civilizations advanced enough to deliberately broadcast signals strong enough for us to detect are likely extremely rare or nonexistent in our galaxy.
Friedman argues that intelligence, technology and civilization may simply be an evolutionary accident unique to humans, rather than inevitabilities of evolution.
Possibilities for the Lack of Discovered Alien Civilizations
Given the size and age of the universe, the lack of any evidence for intelligent alien civilizations is perplexing. Friedman discusses various possible explanations that have been offered.
First, intelligent life may be far rarer than we imagine. Second, alien civilizations may tend to be short-lived for a variety of reasons, going extinct before they can expand significantly into the galaxy. Third, intelligence may not actually provide an evolutionary advantage, and could even be a liability that leads to short lifespans.
With Earth as the only current data point, the issue remains open. Friedman argues that the absence of any hints of intelligence beyond Earth, despite extensive searching, indicates it is likely extremely rare or nonexistent elsewhere in our galaxy.
Possibilities for Basic Alien Life
While intelligence may be scarce, Friedman argues that simpler extraterrestrial life is potentially abundant in the universe. Life arose very quickly on Earth after its formation, suggesting the origin of life may be commonplace on habitable worlds.
Ingredients for life like water and complex organic molecules are widespread throughout the galaxy. The thousands of exoplanets discovered in recent decades include many potentially habitable worlds, where life could exist.
Friedman gives an overview of our own solar system, noting several "ocean world" moons like Europa and Enceladus that may harbor life in warm underground oceans. He argues that while intelligence appears to be extremely rare, basic microbial alien life could be ubiquitous in the cosmos based on what we know so far.
The Limits of Interstellar Travel
Given the possibilities for life within our galaxy, can we travel to and explore potentially habitable exoplanets directly? Unfortunately, Friedman argues, practical interstellar travel is likely impossible. The distances between stars are simply too vast and spacecraft speeds too slow using any currently known means of propulsion.
While theoretical concepts have been proposed, none are remotely practical given the constraints of physics, engineering and cost. Even a voyage to merely the nearest stars would take tens of thousands of years.
More interesting habitable exoplanet destinations are hundreds or thousands of light years away. Alien worlds will have to be explored remotely through telescopes and probes rather than direct visitation.
Using the Sun as a Gravitational Lens
While we cannot travel to exoplanets, Friedman explains that there is a way to use our own sun to observe them at magnifications allowing surface study. Einstein's theory showed gravity bends the path of light rays.
This lensing effect means the Sun can magnify light from a distant exoplanet by a factor of 10 billion. By positioning a telescope at the focal point of this "solar gravitational lens," direct imaging of exoplanets may be possible even over interstellar distances.
This focal line begins at approximately 550 AU from the Sun, in the outer solar system. Reaching this region requires speeds of 35 AU per year, achievable with advanced solar sails on small probes.
A Series of Missions to the Stars
Rather than a single ambitious interstellar probe, Friedman advocates for a series of incremental missions, each pushing farther into the solar system and interstellar medium.
Developing advanced solar sails and testing them on probes to objects like Kuiper Belt objects and interstellar comets will enable eventual capability to reach the solar gravitational lensing focus point.
In concert with improving exoplanet imaging and mapping techniques from Earth and space telescopes, this could allow detailed observations of potentially habitable exoplanets to begin in the 2040s. Multiple small probes using solar gravitational lensing could survey several promising exoplanets simultaneously.
The Dawn of Comparative Astrobiology
What might we find in these direct observations of multiple alien worlds? Detailed imaging could provide clues about extraterrestrial life and biosignatures.
Friedman proposes that a new field of "comparative astrobiology" may emerge. With data from diverse exoplanets, scientists can study how life arises and evolves in different environments. This can provide key insights about the origins and prevalence of life in the cosmos, and help answer fundamental questions about our own existence and evolution.
Even if no technological alien civilizations are found, the study of multiple exoplanets potentially harboring microbial life will revolutionize our understanding of biology.
Alone But Not Lonely
Given the lack of any signals from or evidence for intelligent aliens, Friedman argues that humanity likely stands alone as the sole technological civilization in the Milky Way galaxy, if not the universe.
But while we may be alone, detailed exploration of other worlds teeming with life will prevent us from ever being lonely. Friedman ends on an optimistic and exciting note, envisioning a future where swarms of solar sail probes virtually visit distant exoplanets and beam home detailed data to build immersive 3D models.
He argues this will provide endless frontiers for exploration and discovery for centuries to come, as we uncover deeper insights about life, intelligence and our own existence. Even if we find no alien equivalents, observing myriad new forms of extraterrestrial life will bring us closer to understanding ourselves.
October 15, 2023
As someone who loves thinking and reading about space exploration and the possibility of extraterrestrial life, this book was an enjoyable read. It’s general, spanning multiple fields and issues that relate to the search for extraterrestrial life. The central thesis of the book is that humanity is alone in terms of being the only intelligent life in the galaxy. However, simple microbial life is likely widespread.
I give the book 3 stars because I 1) fundamentally disagree with the central thesis of the book. The author makes a series of assumptions that lead him to boldly and confidently state we are the only ones. Pessimism aside, this line of thinking forgoes further imagination and creativity that galvanizes discoveries of the future. 2) I found some of his biological claims a litttle fast and loose with the facts. Nothing he said was flat out wrong. I have a PhD in Biological sciences and have spent too much time learning about astrobiology and related disciplines. The author has an engineering background. And so when he’s talking about technical challenges to interstellar travel for instance, his strengths show. When talking about biology, the lapse are evident.
Overall, I recommend the book as a way to further sharpen your own views on this topic but reading perhaps a contrarian and more pessimistic viewpoint.
I give the book 3 stars because I 1) fundamentally disagree with the central thesis of the book. The author makes a series of assumptions that lead him to boldly and confidently state we are the only ones. Pessimism aside, this line of thinking forgoes further imagination and creativity that galvanizes discoveries of the future. 2) I found some of his biological claims a litttle fast and loose with the facts. Nothing he said was flat out wrong. I have a PhD in Biological sciences and have spent too much time learning about astrobiology and related disciplines. The author has an engineering background. And so when he’s talking about technical challenges to interstellar travel for instance, his strengths show. When talking about biology, the lapse are evident.
Overall, I recommend the book as a way to further sharpen your own views on this topic but reading perhaps a contrarian and more pessimistic viewpoint.
October 2, 2023
This is a great summary of the work to date on the search for life in the universe, SETI, and a thoughtful perspective on where we might go next with the research. It’s a quick listen or read.
November 22, 2023
I did not care for the book, it reads like a college lecture and was very repetitive. I got the impression that most of it was his opinions.
I will give the caveat that I was looking for an entertaining read instead of a strictly informative one. It may be a great read for class but not a leisurely read.
I will give the caveat that I was looking for an entertaining read instead of a strictly informative one. It may be a great read for class but not a leisurely read.
October 29, 2023
This book is fascinating! Backed with real numbers and statistics, this book did a really great job in changing my whole perspective on topic of interstellar travel. It worths reading.
April 9, 2024
Boring
October 16, 2023
very interesting
A great read for a novice. Fills in gaps that I have never thought about. Was very interesting and very easy to understand
A great read for a novice. Fills in gaps that I have never thought about. Was very interesting and very easy to understand
Displaying 1 - 7 of 7 reviews