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the Complete Review
the complete review - astrobiology

Life in the Cosmos

Manasvi Lingam
Avi Loeb

general information | our review | links | about the authors

To purchase Life in the Cosmos

Title: Life in the Cosmos
Author: Manasvi Lingam and Avi Loeb
Genre: Textbook
Written: 2021
Length: 902 pages
Availability: Life in the Cosmos - US
Life in the Cosmos - UK
Life in the Cosmos - Canada
directly from: Harvard University Press
  • From Biosignatures to Technosignatures

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Our Assessment:

(--) : wide-ranging and staggeringly thorough; a fascinating in-depth overview of the field

See our review for fuller assessment.

The complete review's Review:

       Life in the Cosmos is a textbook on astrobiology -- on 'life', in any form, in the universe, beyond (just) on earth.
       In their Preface, the authors note that:

     Our expectation is that this work will be employed as a textbook by graduate and possibly advanced undergraduate students, while also functioning as a point of reference for professional scientists whose research interests overlap with astrobiology. On account of the monograph's size and scope, we recommend that the contents herein are best covered over a two- or three-semester sequence
       The sheer size and scope of the book can indeed seem daunting: it covers a lot -- from the origins and nature of the most basic forms of life to the potential types of intelligent extraterrestrial life, and, specifically, how we might recognize and/or determine the presence/existence any of these kinds of life (if they are ...) out there, all considered in considerable detail.
       Life in the Cosmos begins with a close examination of 'life' itself, and its origins. While, as the authors note in the book's opening, their principal aim here: "is to address the prospects for extraterrestrial life", the first part of the text, taking up nearly a third of the whole, is devoted to life as we know it -- terrestrial life. Indeed, among much else, Life in the Cosmos is an excellent primer on life on earth, from the very beginnings.
       While acknowledging the possibility of biological life that is based on other biochemistries, their focus is on life-as-we-know-it -- carbon- and water-based. In painstaking detail, Lingam and Loeb consider how it might have originated, with an emphasis on the necessary conditions, as, if we expect to find life-as-we-know-it elsewhere in the universe, similar conditions and circumstances would be strong indicators of at least the possibility of it having come about there in a similar way.
       From 'life' at its most basic they proceed to the evolution of intelligent life, through the terrestrial "five major breakthroughs" they identify: the emergence of life, oxygenic photosynthesis, eukaryotes, animals, and technological intelligence. What happened on earth again remains the guide, but, as all along, they also consider possible alternative paths. (Of course, 'what happened on earth' is also not always clear, and they discuss the various theories that might explain it, too.) Throughout, they also consider the probabilities, as even similar conditions need not necessarily result in the same outcomes, noting about the five major breakthroughs they identify:
Each of these major evolutionary events happened only once on our planet, thus potentially implying that they may have a low likelihood of occurrence on other worlds.
       So also, for example, they note the vital rise of atmospheric oxygen on earth, as a consequence of oxygenic photosynthesis -- and that:
Despite the potential existence of multiple paths towards oxygenic photosynthesis, the possibility that it arose only once on our planet -- and perhaps not very soon after the emergence of life -- might indicate that it represents a difficult evolutionary step that is not readily achievable on exoplanets and exomoons.
       Meanwhile, they show that other leaps along the path to higher forms of life have much better odds
(T)here are strong grounds for supposing that multicellularity could originate with relative ease on other worlds, given the appropriate conditions. It is credible, therefore, that multicellularity constitutes a "minor" major transition.
       The second part of the text considers extraterrestrial biospheres: are there worlds -- planets and moons -- that could sustain some form of life (likely, yes) and what are the local factors that could affect whether or not life can arise and be sustained there, as well as then also what evidence of 'biosignatures' can be determined from our terrestrial vantage point.
       The authors methodically consider the factors involved with habitability, first the stellar factors -- those of the host stars to the relevant bodies -- and then the planetary ones themselves, down to, for example, the distribution of landmasses and oceans. While mostly focused on life in terrestrial or aquatic habitats, they also consider the possibility of life in the atmospheres of other worlds. And, while much of the discussion is about lifeforms evidence of which might be readily detectable, they also consider at some length -- devoting an entire chapter to the subject -- life in subsurface oceans, which is much harder to detect (noting that: "our own Solar system comprises at least three worlds confirmed to possess subsurface oceans").
       The final part of the text considers extraterrestrial technospheres -- essentially, a discussion of the search for intelligent life in the universe. The authors prefer the definition 'Search for Extraterrestrial Technological Intelligence' for SETI rather than the conventional ''Search for Extra Terrestrial Intelligence', focusing on intelligences sufficiently technologically advanced so as to communicate in space. They begin with discussions of the Drake equation -- an estimate of the number of worlds with such advanced life on them -- and then the so-called Fermi Paradox, which basically wonders: if there is advanced intelligence out there, why haven't we come across any ? (Acknowledging that both of these: "may be perceived as philosophical twaddle by some individuals, it is important to recognize that they play a fundamental role in guiding our search strategies and are therefore relevant from a practical standpoint".)
       From there they move on to the various 'technosignatures' that intelligent lifeforms may be leaving -- noting that we may not be looking in the right places or at the right things (with, for example, the search for radio signals).
       A final chapter considers the propagation of life in the universe, specifically the idea of 'panspermia', life being transferred from one world to another. This ranges from discussions of ejecta from one world seeding the next to interstellar rocket travel and the various types of technologically advanced vehicles that might be capable of it.
       It all makes for a truly exhaustive study. While Lingam and Loeb note that they can't, in fact, cover all the possibilities regarding everything they address -- e.g.: "The number of solutions that have been proposed as resolutions of Fermi's paradox total at least over a hundred. As we cannot hope to address all of them, we will focus on a few select examples" --, it often feels that they come close; certainly, they cover and address the main points fully. Life in the Cosmos is a work of staggering thoroughness -- and helpfully they point to the significant as well as recent literature on most everything they cover, for those looking for even more detail. A 117-page bibliography both attests to the breadth of their own research in putting together this volume, as well as gives direction to those interested in following up on specific subjects.
       Life in the Cosmos is a scientific textbook and, as such, much of the writing is fairly technical; the terminology that is used and, especially, the equations can prove challenging to readers without a background in the field(s), with passages such as that below not uncommon:

       In fact, however, at least a general sense of the equations and their implications is generally made quite clear; even if the equations are a skimmed blur, a close reading of the surrounding text can keep even the lay-reader from feeling too much at sea -- for the most part. If some of the science -- especially when reduced to symbol-heavy equations -- is, in its specifics and calculation, beyond the amateur, the authors explain it clearly enough along the way to convey the gist (and there is a lot of gist).
       As Lingam and Loeb already suggested in their Preface:
We strove to arrive at the right balance between conveying a substantial amount of technical information and expressing ourselves in an engaging and insightful fashion. We are of the opinion that scientific writing these days tends to emphasize the former aspect at the latter's expense, thus reducing many textbooks to theory or intimidating compendiums of facts, figures, and equations. [...] (W)e have opted to eschew an orthodox approach that is exclusively oriented toward the explication of technical details and endeavored instead to enkindle and inculcate a genuine passion for the subject by enhancing the readability of this tome
       They have succeeded quite well at this, presenting a vast amount of material in both relatively accessible as well as engaging form. (As they also already noted in their Preface: "A number of quotations and epigraphs are consequently interwoven throughout the book to enliven the accompanying discussion while preserving didacticism"; the (often literary) selection, ranging from passages from Virginia Woolf to Shelley and Neruda, Thoreau to Lomonosov, and even the Heike monogatari, is fairly on point while also making for splash of a quite different color, and even if they can at times seem like over-fancy frills, there's little harm in that.)
       Life in the Cosmos is almost endlessly fascinating, even for those who stumble along mainly at the surface. From the discussions of how life can arise to planetary conditions allowing for life to evolve and be sustained and the technological capabilities necessary for interstellar travel, Life in the Cosmos is both incredibly wide-ranging and constantly fascinating. Reading distant biosignatures with the still limited capabilities we have would seem almost impossible, but the authors show how suggestive a variety of evidence actually is. Actual proof of life is hard to come by, for now, but there are tantalizing possibilities to explore.
       As a textbook, Life in the Cosmos would seem to fulfil its function exceptionally well, presenting and covering the subject matter very well and helpfully pointing readers to where else they can follow up specific points in greater detail. Life in the Cosmos also holds considerable appeal for the lay-reader. Despite being technically challenging, it offers so much that it should also be rewarding for anyone interested in the field.

- M.A.Orthofer, 30 December 2021

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Life in the Cosmos: Reviews: Manasvi Lingam: Avi Loeb: Other books of interest under review:

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About the Authors:

       Manasvi Lingam teaches at the Florida Institute of Technology.

       Avi Loeb teaches at Harvard.

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© 2021 the complete review

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