William Bains

William Bains
Massachusetts Institute of Technology | MIT · Department of Earth Atmospheric and Planetary Sciences

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226
Publications
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Publications

Publications (226)
Article
New analysis is presented of the 1.1 mm wavelength absorption lines in Venus’ atmosphere that suggested the presence of phosphine. We retrieve a sulphur dioxide observation from the JCMT archive that was simultaneous within a few days of the PH3 1-0 spectrum obtained in June 2017, and demonstrate via a radiative transfer calculation that contaminat...
Article
About 2.5 billion years ago, microbes learned to harness plentiful solar energy to reduce CO 2 with H 2 O, extracting energy and producing O 2 as waste. O 2 production from this metabolic process was so vigorous that it saturated its photochemical sinks, permitting it to reach “runaway” conditions and rapidly accumulate in the atmosphere despite it...
Article
Full-text available
The thermodynamic properties of a substance are key to predicting its behavior in physical and chemical systems. Specifically, the enthalpy of formation and entropy of a substance can be used to predict whether reactions involving that substance will proceed spontaneously under conditions of constant temperature and pressure, and if they do, what t...
Preprint
Full-text available
About 2.5 billion years ago, microbes learned to harness plentiful Solar energy to reduce CO$_2$ with H$_2$O, extracting energy and producing O$_2$ as waste. O$_2$ production from this metabolic process was so vigorous that it saturated its photochemical sinks, permitting it to reach "runaway" conditions and rapidly accumulate in the atmosphere des...
Article
Full-text available
The initial reports of the presence of phosphine in the cloud decks of Venus have led to the suggestion that volcanism is the source of phosphine, through volcanic phosphides ejected into the clouds. Here, we examine the idea that mantle plume volcanism, bringing material from the deep mantle to the surface, could generate observed amounts of phosp...
Article
Full-text available
The atmosphere of Venus remains mysterious, with many outstanding chemical connundra. These include the unexpected presence of ∼10 ppm O 2 in the cloud layers, an unknown composition of large particles in the lower cloud layers, and hard to explain measured vertical abundance profiles of SO 2 and H 2 O. We propose a hypothesis for the chemistry in...
Preprint
Full-text available
The atmosphere of Venus remains mysterious, with many outstanding chemical connundra. These include: the unexpected presence of ~10 ppm O2 in the cloud layers; an unknown composition of large particles in the lower cloud layers; and hard to explain measured vertical abundance profiles of SO2 and H2O. We propose a new hypothesis for the chemistry in...
Preprint
Full-text available
The initial reports of the presence of phosphine in the cloud decks of Venus has led to the suggestion that volcanism was the source of phosphine, through volcanic phosphides ejected into the clouds. Here we examine the idea that mantle plume volcanism, bringing material from the deep mantle to the surface, could generate observed amounts of phosph...
Preprint
Full-text available
The potential detection of ppb levels phosphine (PH3) in the clouds of Venus through millimeter-wavelength astronomical observations is extremely surprising as PH3 is an unexpected component of an oxidized environment of Venus. A thorough analysis of potential sources suggests that no known process in the consensus model of Venus' atmosphere or geo...
Article
The potential detection of ppb levels phosphine (PH3) in the clouds of Venus through millimeter-wavelength astronomical observations is extremely surprising as PH3 is an unexpected component of an oxidized environment of Venus. A thorough analysis of potential sources suggests that no known process in the consensus model of Venus’ atmosphere or geo...
Preprint
Full-text available
New analysis is presented of the 1.1 mm wavelength absorption lines in Venus' atmosphere that suggested the presence of phosphine. We confirm that ALMA detected absorption at the PH3 1-0 wavelength in 2019, from an optimised spectrum covering half of the planetary disc. Sulphur dioxide line-contamination was then <10%, from modelling of a simultane...
Article
The recent candidate detection of ∼1 ppb of phosphine in the middle atmosphere of Venus is so unexpected that it requires an exhaustive search for explanations of its origin. Phosphorus-containing species have not been modeled for Venus' atmosphere before, and our work represents the first attempt to model phosphorus species in the venusian atmosph...
Article
Full-text available
Measurements of trace gases in planetary atmospheres help us explore chemical conditions different to those on Earth. Our nearest neighbour, Venus, has cloud decks that are temperate but hyperacidic. Here we report the apparent presence of phosphine (PH3) gas in Venus’s atmosphere, where any phosphorus should be in oxidized forms. Single-line milli...
Article
The search for biosignatures is likely to generate controversial results, with no single biosignature being clear proof of the presence of life. Bayesian statistical frameworks have been suggested as a tool for testing the effect that a new observation has on our belief in the presence of life on another planet. We test this approach here using the...
Preprint
Full-text available
The search for signs of life through the detection of exoplanet atmosphere biosignature gases is gaining momentum. Yet, only a handful of rocky exoplanet atmospheres are suitable for observation with planned next-generation telescopes. To broaden prospects, we describe the possibilities for an aerial, liquid water cloud-based biosphere in the atmos...
Article
Full-text available
The search for signs of life through the detection of exoplanet atmosphere biosignature gases is gaining momentum. Yet, only a handful of rocky exoplanet atmospheres are suitable for observation with planned next-generation telescopes. To broaden prospects, we describe the possibilities for an aerial, liquid water cloud-based biosphere in the atmos...
Article
Full-text available
We present a model of the evolution of control systems in a genome under environmental constraints. The model conceptually follows the Jacob and Monod model of gene control. Genes contain control elements which respond to the internal state of the cell as well as the environment to control expression of a coding region. Control and coding regions e...
Article
Full-text available
The chemistry of life requires a solvent, which for life on Earth is water. Several alternative solvents have been suggested, but there is little quantitative analysis of their suitability as solvents for life. To support a novel (non-terrestrial) biochemistry, a solvent must be able to form a stable solution of a diverse set of small molecules and...
Preprint
Full-text available
We recover PH3 in the atmosphere of Venus in data taken with ALMA, using three different calibration methods. The whole-planet signal is recovered with 5.4{\sigma} confidence using Venus bandpass self-calibration, and two simpler approaches are shown to yield example 4.5-4.8{\sigma} detections of the equatorial belt. Non-recovery by Villanueva et a...
Article
Research for possible biosignature gases on habitable exoplanet atmosphere is accelerating. We add isoprene, C5H8, to the roster of biosignature gases. We found that formation of isoprene geochemical formation is highly thermodynamically disfavored and has no known abiotic false positives. The isoprene production rate on Earth rivals that of methan...
Preprint
Full-text available
Research for possible biosignature gases on habitable exoplanet atmosphere is accelerating. We add isoprene, C5H8, to the roster of biosignature gases. We found that formation of isoprene geochemical formation is highly thermodynamically disfavored and has no known abiotic false positives. The isoprene production rate on Earth rivals that of methan...
Article
Full-text available
We describe a dataset of the quantitative reactivity of organic chemicals with concentrated sulfuric acid. As well as being a key industrial chemical, sulfuric acid is of environmental and planetary importance. In the absence of measured reaction kinetics, the reaction rate of a chemical with sulfuric acid can be estimated from the reaction rate of...
Preprint
Full-text available
We present a model of the evolution of control systems in a genome under environmental constraints. The model conceptually follows the Jacob and Monod model of gene control. Genes contain control elements which respond to the internal state of the cell as well as the environment to control expression of a coding region. Control and coding regions e...
Preprint
Full-text available
We published spectra of phosphine molecules in Venus' clouds, following open-science principles in releasing data and scripts (with community input leading to ALMA re-processing, now benefiting multiple projects). Some misconceptions about de-trending of spectral baselines have also emerged, which we address here. Using the JCMT PH3-discovery data,...
Preprint
Full-text available
We first respond to two points raised by Villanueva et al. We show the JCMT discovery spectrum of PH3 can not be re-attributed to SO2, as the line width is larger than observed for SO2 features, and the required abundance would be an extreme outlier. The JCMT spectrum is also consistent with our simple model, constant PH3-abundance with altitude, w...
Preprint
Full-text available
The recent candidate detection of 20 ppb of phosphine in the middle atmosphere of Venus is so unexpected that it requires an exhaustive search for explanations of its origin. Phosphorus-containing species have not been modelled for Venusian atmosphere before and our work represents the first attempt to model phosphorus species in Venusian atmospher...
Preprint
Full-text available
We revisit the hypothesis that there is life in the Venusian clouds to propose a life cycle that resolves the conundrum of how life can persist aloft for hundreds of millions to billions of years. Most discussions of an aerial biosphere in the Venus atmosphere temperate layers never address whether the life-small microbial-type particles-is free fl...
Preprint
Full-text available
Measurements of trace-gases in planetary atmospheres help us explore chemical conditions different to those on Earth. Our nearest neighbor, Venus, has cloud decks that are temperate but hyper-acidic. We report the apparent presence of phosphine (PH3) gas in Venusian atmosphere, where any phosphorus should be in oxidized forms. Single-line millimete...
Article
Full-text available
We revisit the hypothesis that there is life in the Venusian clouds to propose a life cycle that resolves the conundrum of how life can persist aloft for hundreds of millions to billions of years. Most discussions of an aerial biosphere in the Venus atmosphere temperate layers never address whether the life-small microbial-type particles-is free fl...
Article
Full-text available
Despite more than one hundred years of work on organosilicon chemistry, the basis for the plausibility of silicon-based life has never been systematically addressed nor objectively reviewed. We provide a comprehensive assessment of the possibility of silicon-based biochemistry, based on a review of what is known and what has been modeled, even incl...
Article
Full-text available
David Deamer has written another book, Assembling Life, on the origin of life. It is unapologetically polemic, presenting Deamer’s view that life originated in fresh water hydrothermal fields on volcanic islands on early Earth, arguing that this provided a unique environment not just for organic chemistry but for the self-assembling structure that...
Article
Full-text available
A long-term goal of exoplanet studies is the identification and detection of biosignature gases. Beyond the most discussed biosignature gas O2, only a handful of gases have been considered in detail. In this study, we evaluate phosphine (PH3). On Earth, PH3 is associated with anaerobic ecosystems, and as such, it is a potential biosignature gas in...
Preprint
Full-text available
A long-term goal of exoplanet studies is the identification and detection of biosignature gases. Beyond the most discussed biosignature gas O$_2$, only a handful of gases have been considered in detail. Here we evaluate phosphine (PH$_3$). On Earth, PH$_3$ is associated with anaerobic ecosystems, and as such is a potential biosignature gas on anoxi...
Chapter
Luftsauerstoff ist für das tierische Leben unverzichtbar, vor allem für uns selbst. Ein gesunder erwachsener Mensch kann zwei Wochen ohne Nahrung und mehrere Tage ohne Wasser aushalten, aber nicht mehr als fünf Minuten ohne Sauerstoff, ohne bleibende Schäden davonzutragen. Jedes Schulkind weiß, dass grüne Pflanzen die Energie des Sonnenlichts nutze...
Chapter
Wir hoffen, dass wir bisher überzeugend darlegen konnten, dass viele der Dinge, die komplexe Organismen wie wir besitzen – eukaryotische Zellen, Mehrzelligkeit, Sex – und andere, von denen wir abhängig sind, wie Sauerstoff, wahrscheinliche Folgen des Lebens sind, nachdem es sich auf der Erde vor 3,5 Mrd. Jahren entwickelt hatte. Aber das Auftauchen...
Chapter
Wir widmen uns nun der Frage, ob ein Planet grundsätzlich Leben aufrechterhalten kann. Die Minimalvoraussetzungen für komplexes Leben sind deutlich höher als für mikrobielles. Wir werden zuerst überlegen, was unsere Erde zu einem bewohnbaren Planeten macht und inwiefern ihre Geschichte im Sonnensystem eng mit dem Auftauchen und dem Fortbestand von...
Chapter
Wir können die Hypothese vom lebendigen Universum heute nicht testen, doch eines Tages werden wir so weit sein, denn wir werden immer bessere Fernerkundungen durchführen können, und vielleicht werden wir einmal geeignete Exoplaneten und Exomonde besuchen können. Die schlechte Nachricht ist, dass dies immer noch Jahrzehnte dauern wird, die gute, das...
Chapter
Der bedeutendste Moment in der Geschichte des Lebens auf unserem Planeten ist sein Ursprung. Viele der ersten Wissenschaftler, die sich mit dem Phänomen Leben auseinandergesetzt haben, waren der Ansicht, dass „tote Materie“ und Energie allein das Leben nicht erklären können und dass es einen wesentlichen Bestandteil geben müsse, der lebende Organis...
Chapter
Alles Leben besteht aus Zellen. Einzellige Organismen bestehen, wie der Namen schon sagt, aus nur einer Zelle, auch wenn diese Zelle außerordentlich komplex sein kann. Vielzeller verfügen nicht nur über viele Zellen, sondern auch zahlreiche unterschiedliche.
Chapter
Die Welt der Prokaryoten setzt sich aus Archaebakterien und Bakterien zusammen, die allein aufgrund ihrer schieren Anzahl unsere Welt beherrschen. Doch die Evolution führte zu einer immer höheren Komplexität, und die Entstehung eines weiteren wichtigeren Zelltyps, der eukaryotischen Zelle, stellte dabei eine entscheidende Innovation dar. Zwar sind...
Chapter
Im vorhergehenden Kapitel haben wir gesehen, dass viele Tiergruppen die Fähigkeit entwickelt haben, Werkzeuge zu verwenden, Probleme zu lösen, vorauszuplanen und komplexes Verhalten zu lernen. Doch es gibt nur eine Spezies, die diese Fähigkeiten so außerordentlich stark ausgeprägt besitzt, dass sie eine eigene Klasse bildet; diese Spezies ist natür...
Chapter
Menschen, oder zumindest die Menschen, die dieses Buch lesen, sind oft stolz auf ihre Intelligenz. Die Menschen haben die fortschrittlichste materielle Kultur und das komplizierteste und flexibelste Kommunikationssystem aller Wesen auf der Erde. Doch auch viele Tiere haben Fähigkeiten, die auf ein erhebliches Maß an Intelligenz schließen lassen.
Chapter
Am Anfang dieses Buches haben wir die Idee des großen Filters vorgestellt, etwas, das zwischen der Entstehung von Planeten (vom dem wir wissen, dass es oft passiert) und der Existenz technologischer Zivilisationen (die selten zu sein scheinen) steht. Wir haben uns gefragt, was dieser große Filter wohl sein könnte, und vermutet, dass es sich im Lauf...
Chapter
Wenn Menschen meinen, Sex sei wichtig, haben sie vermutlich Recht. Aber wenn Biologen über die Vermehrung durch Sex sprechen, meinen sie nicht den Spaß und die Intimität. Das ist ziemlich nebensächlich. Bei der sexuellen Revolution geht es darum, wie zwei Individuen ihre Gene vermischen und so ein neues Individuum erzeugen. Das ist einer der entsch...
Chapter
Vermutlich wurde das Leben zu Beginn von Reaktionen zwischen chemischen Stoffen – vor allem aus Gestein und Gasen – angetrieben, die bereits in der Umgebung der jungen Erde vorhanden waren. Wenn Leben an hydrothermalen Quellen in den Tiefen der Ozeane entstanden ist, dann reagierten das vulkanische Gestein und die Gase, die von diesen Vulkanen ausg...
Chapter
In diesem Buch werden wir begründen, warum die Entwicklung komplexen Lebens in jeder stabilen Umgebung mit ausreichend Lebensraum sehr wahrscheinlich ist, sobald auf einem planetaren Körper einmal Leben entstanden ist. Das komplexe Leben auf der Erde sind die echten (obligaten) Lebensformen aus vielen Zellen, vor allem die Mitglieder aus den Reiche...
Article
Phosphorus is an essential element for all life on Earth, yet trivalent phosphorus (e.g., in phosphines) appears to be almost completely absent from biology. Instead phosphorus is utilized by life almost exclusively as phosphate, apart from a small contingent of other pentavalent phosphorus compounds containing structurally similar chemical groups....
Article
Full-text available
Phosphorous-containing molecules are essential constituents of all living cells. While the phosphate functional group is very common in small molecule natural products, nucleic acids, and as chemical modification in protein and peptides, phosphorous can form P–N (phosphoramidate), P–S (phosphorothioate), and P–C (e.g., phosphonate and phosphinate)...
Book
Sind wir allein im Universum? Dieses Buch bietet eine einzigartige Perspektive auf die Frage, die die Menschheit von Anbeginn beschäftigt. In klarem und allgemein verständlichem Stil untersuchen zwei führende Forscher aus der Astrobiologie die verschiedenen Wege, die zu einer vielfältigen Biosphäre führen. Ist der Mensch eine galaktische Besonderhe...
Article
We present a new model for the biological production of phosphine (PH3). Phosphine is found globally, in trace amounts, in the Earth's atmosphere. It has been suggested as a key molecule in the phosphorus cycle, linking atmospheric, lithospheric and biological phosphorus chemistry. Phosphine's production is strongly associated with marshes, swamps...
Article
A fundamental goal of biology is to understand the rules behind life's use of chemical space. Established work focuses on why life uses the chemistry that it does. Given the enormous scope of possible chemical space, we postulate that it is equally important to ask why life largely avoids certain areas of chemical space. The nitrogen-sulfur bond is...
Article
We examine self-experimentation ethics history and practice, related law, use scenarios in universities and industry, and attitudes. We show through analysis of the historical development of medical ethics and regulation, from Hippocrates through Good Clinical Practice that there are no ethical barriers to self-experimentation. When the self-experi...
Article
Upcoming telescopes might be able to detect signatures of complex life on other worlds, but we need to involve physical, chemical and life scientists at the planning stage in order to interpret the findings when the time comes.
Article
Only about 100 natural products are known to contain a nitrogen-sulfur (N-S) bond. This review thoroughly categorizes N-S bond-containing compounds by structural class. Information on biological source, biological activity, and biosynthesis is included, if known. We also review the role of N-S bond functional groups as post-translational modificati...
Article
Sophisticated life forms will prove to be remarkably common in the universe, say Dirk Schulze-Makuch and William Bains
Chapter
Oxygen in the air is essential for animal life, especially our own. A healthy adult human can go 2 weeks or more without food, several days without water, but no more than 5 minute without oxygen before he or she suffers irreversible damage. Every schoolchild knows that green plants use the energy of sunlight to make the oxygen that we breath. The...
Chapter
Humans, or at least the humans reading this book, pride themselves on their intelligence. Humans have by far the most advanced material culture and sophisticated, flexible communication system of any creature on Earth. But many animals show accomplishments that suggest substantial intelligence. So what is intelligence, and how likely is it to arise...
Chapter
People think sex is important. They may be right.
Chapter
Before we start to discuss how life evolves on a planet, we have to address whether a planet can support life even in principle. The minimum requirements are at a higher bar for complex life than for microbial life. We will start our discussion by reviewing what makes Earth a habitable planet, and how our planetary history is closely interwoven wit...
Chapter
At the start of this book we introduced the idea that complex life evolved from simple life in a number of key steps or innovations. Our hypothesis is that all the steps in this progression have happened many times on Earth, and so are likely to occur on other worlds. In Part II of this book, we found that most of those transitions are likely Many...
Chapter
In the last chapter we pointed out that many different groups of animals have evolved the ability to use tools, solve problems, plan ahead, and learn complex behaviour. But there was one species whose ability to do this is so extraordinary that it belongs in a class of its own. That species is, of course, our own: Homo sapiens.
Chapter
All life is made up of cells. Unicellular organisms, as the name suggests, have just one cell, although that cell can be enormously complex. Multicellular organisms contain not just many cells, but critically they contain cells that are different from each other. Originating from a single egg, they develop into different cell types that have differ...
Chapter
In this book, we will argue that the evolution of complex life is highly likely in any stable, sufficiently extensive environment once life originated on a planetary body.
Chapter
Full-text available
In the beginning of this book we introduced the idea of a Great Filter, something that stood between the formation of planets (which we know is common) and the existence of technological civilizations (which seems rare). We asked ourselves where the Great Filter may be and surmised that it may be located in principle at any of the many steps that h...
Chapter
Full-text available
When life started it was likely powered by chemical reactions between chemicals—primarily rocks and gases—that were already present in the early Earth environment. If life originated at hydrothermal vents deep in the sea (as we think is a distinct possibility, as discussed in the last chapter), the volcanic rocks and the gases from volcanic exhalat...
Chapter
So far in this book we have argued, we hope persuasively, that many things possessed by complex organisms such as ourselves—eukaryotic cells, multicellularity, sex—and things we depend on, such as oxygen, were likely outcomes once life was established on Earth 3.5 billion years ago. But we have scarcely mentioned the appearance of large organisms t...
Chapter
The prokaryotic world is composed of the domains Archaea and Bacteria (Box 1.1), which dominate our planet based on their sheer numbers. However, in the evolution of increasing complexity, the emergence of another major type of cell, the eukaryotic cell, was a critical innovation. While many eukaryotes are single-celled organisms, as are bacteria,...
Chapter
The most monumental event in life’s history on our planet is its origin. Many early scientists, trying to understand the phenomenon of life, thought that ‘dead’ matter and energy alone cannot explain life, and that there must be a vital essence in living organisms that distinguishes them from the non-living world. Our current understanding refutes...
Article
Full-text available
Exoplanet science promises a continued rapid accumulation of rocky planet observations in the near future, energizing a drive to understand and interpret an unprecedented wealth of data to search for signs of life. The large statistics of exoplanet samples, combined with the ambiguity of our understanding of universal properties of life and its sig...
Article
Full-text available
Finding life on exoplanets from telescopic observations is the ultimate goal of exoplanet science. Life produces gases and other substances, such as pigments, which can have distinct spectral or photometric signatures. Whether or not life is found in future data must be expressed with probabilities, requiring a framework for biosignature assessment...
Book
Are humans a galactic oddity, or will complex life with human abilities develop on planets with environments that remain habitable for long enough? In a clear, jargon-free style, two leading researchers in the burgeoning field of astrobiology critically examine the major evolutionary steps that led us from the distant origins of life to the technol...
Article
Full-text available
Background: The chemicals of metabolism are constructed of a small set of atoms and bonds. This may be because chemical structures outside the chemical space in which life operates are incompatible with biochemistry, or because mechanisms to make or utilize such excluded structures has not evolved. In this paper I address the extent to which bioch...
Chapter
All complex multicellular organisms are eukaryotes. How did the evolution of the highly complex architecture of the eukaryotic cell arise? I discuss the differences between bacteria and archaea (prokaryotes) and eukaryotes in terms of chemistry, cellular structure, energetic and genetics. Chemistry and cell structure are less diagnostic of eukaryot...
Article
Biotechnology is viewed as an industry that combines scientific innovation, entrepreneurial management and experienced investment to drive innovation, primarily in biomedicine. This paper examines the third of these assumed preconditions. We find that the majority of investors in biotechnology companies over the last decade by number or by value ha...
Article
Full-text available
Life on Earth provides a unique biological record from single-cell microbes to technologically intelligent life forms. Our evolution is marked by several major steps or innovations along a path of increasing complexity from microbes to space-faring humans. Here we identify various major key innovations, and use an analytical toolset consisting of a...