III. An Organic Habitable Zone UniVerse
H. An Astrochemistry to Astrobiological Fertility
Into the 2000s and 2010s an exceptional Earthkinder has widely and deeply explored our celestial stellar, galactic and universal environs with regard to its material composition. Rather than a lumpen sterility, a flow of findings has increasingly revealed a natural propensity to form and complexify into an array of lively biochemical precursors. That is to say, a revolutionary organic procreative spontaneity has become its inherent essence. A novel ecosmos thus appears to be “pregnant with life” as the Nobel chemist Christian de Duve famously said.
ABSCICON Astrobiology Science Conference 2015: Habitability, Habitable Worlds, and Life. www.hou.usra.edu/meetings/abscicon2015. This June event in Chicago with many premier presenters conveys how these Earthwise frontiers of a fertile genesis cosmos that fills itself with an evolutionary emergence of ovular bioplanets presages such a 21st century revolution. The list of papers and posters runs into the hundreds. The week opened with a plenary talk by James Kasting on Sustained Habitability on a Dynamic Early Earth. Concurrent sessions each day such as The Diversity of Worlds: Comparative Planetology and Habitability, Major Transitions in Evolution: Catalysts and Constraints, and Laws of Life: Exploring Universal Biology proceeded to imply an inherently life-friendly universe. Extended abstracts are available on a Program page, everyone in the field seemed to speak such as Sara Walker, Paul Davies, Lisa Kaltenegger, Leroy Cronin, Nigel Goldenfeld, Charles Lineweaver, Robert Hazen, and Abel Mendez. A few titles are Chance and Necessity in the Mineral Evolution of Terrestrial Planets, On Detecting Biospheres from Thermodynamic Disequilibrium in Planetary Atmospheres, and The Emergence of Life as a First Order Phase Transition. See also AbSciCon 2017 in Organic Cosmos for a further focus on Diverse Life and its Detection on Different Worlds, by a similar stellar cast.
Recent years have witnessed dramatic advances in our understanding of the early steps in the transition from a prebiotic world to a world transformed by a biotic component. These early steps are presumed to include the evolution of collectively autocatalytic networks of molecules, as well as the evolution of protocells that define the boundary between living and non-living matter. Since the earliest cellular life, innovations caused by gene duplication and divergence, novel gene fusions/fission, and transfer of genes between phylogenetically distinct groups have led to an explosive diversification of the metabolic and regulatory networks within cells, enabling colonization of new environmental niches as well as new mechanisms for cooperative interactions between cells. The hierarchy of life — genes within genomes, organelles within cells, cells within organisms, and organisms within societies — is not a starting condition of the evolutionary process, but an outcome of a series of major transitions in which units of low complexity combine to form units of high complexity. Ongoing revolutions in genomics and informatics are giving new insights into the process by which such transitions occur. (The Origin and Subsequent Evolution of Life Plenary Session)
European Space Administration. www.lifeinuniverse.org/noflash/liu. An informative, graphic exposition from Cosmology to the Origin of Life and onto Social Implications.
List of Interstellar and Circumstellar Molecules. en.wikipedia.org/wiki/List_of_interstellar_and_circumstellar_molecules.. A comprehensive, up-to-date Wikipedia posting that in March 2014 cited over 200 complex, mostly organic, compounds in the cosmic spacescape. They are neatly arranged in classes of diatomic, triatomic, then four to ten or more atoms, denatured, and others.
National Aeronautics and Space Administration NASA. www.astrobiology.arc.nasa.gov. One of the premier science and cosmic panorama sites on the Internet.
Anbar, Ariel and Edna DeVore. The Astrobiology Science Conference 2008. Astrobiology. 8/2, 2008. An introduction to the Abstracts from 39 Sessions with hundreds of papers across the widest range that a sentient bioplanet beginning to survey its natural, solar, galactic, and cosmic environs could obtain. For an example of topics: Human Exploration of Mars, Astrovirology, Habitable Extrasolar Planets, Universal Intelligence, and Microbial Consortiums. Plenary speakers included Sir Martin Rees, Paul Davies, and Sara Seager. The above authors note that this annual Santa Clara, CA meeting began modestly in 2000 and is now a major international event. But a common philosophical vista and quest is not joined in the contributions which could realize a greater phenomenal, self-witnessing genesis. Yet our sample quotes can convey an imminent, salutary cosmic Copernican revolution if we might be so mindful.
In this talk, we discuss the prospects for a new cosmological modeling paradigm which treats the evolution of the universe in full generality, as the complex, nonlinear dynamical system that it is. We will explore the possibility that the emergence of complex structures will in turn provide insight into the likelihood of the emergence of life in the universe. (419, Steven Weinstein)
Arney, Gilda, et al. Organic Haze as a Biosignature in Anoxic Earth-like Atmospheres. International Journal of Astrobiology. 18/4, 2018. GA and Shawn Domagal-Goldman, NASA Goddard Space Flight Center, and Victoria Meadows, NASA Astrobiology Institute, report how the early Earth (Archean eon 3.8–2.5 billion years ago) was covered a complex haze such as biogenic organic sulfur gases (CS2, OCS, CH3SH, and CH3SCH3) within complex clouds of precursor chemicals. As this vital envelope becomes more specified, its properties can serve as a reference for evaluating exoplanets with regard to their relative habitability.
Bains, William. What do We Think Life Is? International Journal of Astrobiology. Online September, 2013. A British astrobiologist associated with Earth and Planetary Sciences, MIT, and SENS Research Foundation Laboratory, Cambridge, UK, contends that this fledgling field needs a better definition of what “living things” are to rightly proceed. Four vital properties are then cited: complex structure, dynamic self-maintenance, natural groups of organisms, and an internal formative code. These qualities are also seen to complement the “programme-metabolism-container” triad of theorist Mark Bedau and others.
The conundrum of finding a ‘definition’ for life can be side-stepped by asking how people actually identify examples of life, and using this as the basis for life detection strategies. I illustrate how astrobiologists actually select things that are living from things that are not living with a simple exercise, and use this as the starting point to develop four characteristics that underlie their decisions: highly distinctive structure (physical or chemical), dynamic behaviour (physical or chemical), multiple instances of life forming a ‘natural group’ and that the structural and dynamic characteristics of the group are independent of the details of the substrate on which life is growing. I show that these all derive the role of a code in the dynamic maintenance and propagation of life. I argue that evolution is neither a useful nor a practical way of identifying life. I conclude with some specific ways that these general categories of the observable properties of life can be detected. (Abstract)
Berne, Olivier and A. G. G. M. Tielens. Formation of Buckminsterfullerene (C60) in Interstellar Space. Proceedings of the National Academy of Sciences. 109/401, 2012. As the Abstract details, Leiden University astrochemists are able to add the discovery of this megamolecule to a conducive nebulae nursery filled with complex biological precursors.
Buckminsterfullerene (C60) was recently confirmed as the largest molecule identified in space. However, it remains unclear how and where this molecule is formed. It is generally believed that C60 is formed from the buildup of small carbonaceous compounds in the hot and dense envelopes of evolved stars. Analyzing infrared observations, obtained by Spitzer and Herschel, we found that C60 is efficiently formed in the tenuous and cold environment of an interstellar cloud illuminated by strong ultraviolet (UV) radiation fields. This implies that another formation pathway, efficient at low densities, must exist. Based on recent laboratory and theoretical studies, we argue that polycyclic aromatic hydrocarbons are converted into graphene, and subsequently C60, under UV irradiation from massive stars. This shows that alternative—top-down—routes are key to understanding the organic inventory in space. (Abstract, 401)
Bishop, Shawn and Ramon Egli. Discovery Prospects for a Supernova Signature of Biogenic Origin. Icarus. 212/2, 2011. As the Abstract details, European astrophysicists report a remarkable indication of a biologically active and intrinsically fecund interstellar milieu. The Abstract contains the fascinating technical details. Who are we Homo Sapiens to be able to do and find such revelations?
Approximately 2.8 Myr before the present our planet was subjected to the debris of a supernova explosion. The terrestrial proxy for this event was the discovery of live atoms of 60Fe in a deep-sea ferromanganese crust. The signature for this supernova event should also reside in magnetite (Fe3O4) microfossils produced by magnetotactic bacteria extant at the time of the Earth-supernova interaction, provided the bacteria preferentially uptake iron from fine-grained iron oxides and ferric hydroxides. Using estimates for the terrestrial supernova 60Fe flux, combined with our empirically derived microfossil concentrations in a deep-sea drill core, we deduce a conservative estimate of the 60Fe fraction as 60Fe/Fe ≈ 3.6 × 10−15. This value sits comfortably within the sensitivity limit of present accelerator mass spectrometry capabilities. The implication is that a biogenic signature of this cosmic event is detectable in the Earth’s fossil record. (Abstract, 960)
Blake, Geoffrey and Edwin Bergin. Prebiotic Chemistry on the Rocks. Science. 520/161, 2015. Praise for a paper The Comet-Like Composition of a Protoplanetary Disk as Revealed by Complex Cyanides (Karin Oberg) in the same issue about the detection of organic nitrile compounds in embryonic solar systems. The implication is “a vast reservoir of ice and volatile species that seed the surfaces of young rocky planets or moons.”
Blandford, Roger, Chairperson. New Worlds, New Horizons in Astronomy and Astrophysics. Washington, DC: National Academies Press, 2010. A report of the Committee for a Decadal Survey of Astronomy and Astrophysics of the National Research Council, available in full text and color online at the NAP site, Google title keywords. We quote one sample of its multi-media scope and forward-looking optimism. A grand collaborative mission statement indeed, albeit national, but quite at odds and in contrast with the despair of physical cosmologists convinced to their satisfaction of a hostile, moribund multiverse. Surely this dichotomy needs to be faced and resolved.
Giving Meaning to the Data: Cyber-Discovery The powerful (satellite) surveys described above will produce about a petabyte (1 million gigabytes) of data—roughly as much data as the total that astronomers have ever handled—every week. The data must be quickly sifted so that interesting phenomena can be identified rapidly for further study at other wavelengths. Interesting phenomena could also be discovered by cross-correlating surveys at different wavelengths. Vast numbers of images must be accurately calibrated and stored so that they can be easily accessed to look for motion or unusual behavior on all timescales. As daunting as it sounds, the technology and software that enable the accessing and searching of these enormous databases are improving all the time and will enable astronomers to search the sky systematically for rare and unexpected phenomena. This is a new window on the universe that is opening thanks to the computer revolution. (45)
Boss, Alan, et al. Bioastronomy 2004 Abstracts. Astrobiology. 4/2, 2004. The issue contains over 200 abstracts from this meeting in Reykjavik, Iceland in July. Held every three years under the auspices of the International Astronomical Union, the papers range widely from definitions and origins of life, how stars and planets form, satellite explorations, to the evolution and role of intelligence and technology.