III. Ecosmos: A Revolutionary Fertile, Habitable, Solar-Bioplanet, Incubator Lifescape

I. Our EarthMost Distinction: A Rare Planetary Confluence of Favorable Conditions for Life in Person

Dehant, Veronique, et al. Geoscience for Understanding Habitability in the Solar System and Beyond. Space Science Reviews. 215/42, 2019. Eighteen researchers from six European countries survey of how a wide range of variable internal and external geological and environmental conditions might affect a planet’s hospitality for evolutionary life. A tour is first taken of the Early Earth, Mars, Venus and outer worlds. How study of near and far exoplanets might progress is then scoped out. And as one reads along, it strikes how such a 21st century contribution as this need be attributed to an as yet unidentified worldwise, collective entity learning by her/his own self.

This paper reviews habitability conditions for a terrestrial planet from the point of view of geosciences. It addresses how interactions between the interior of a planet or a moon and its surface atmosphere, hydrosphere and biosphere might be able to sustain life. We address and debate questions issues such as: How do core and mantle affect the evolution and habitability of planets; Mantle overturn on the evolution of the interior and atmosphere; What is the role of the global carbon and water cycles; The influence of comet and asteroid impacts on the evolution of the planet; How does life interact with the evolution of the Earth’s geosphere and atmosphere; and How can knowledge of the solar system geophysics and habitability be applied to exoplanets. (Abstract excerpt, edit)

Dosovic, Vladimir, et al. Advanced Aspects of the Galactic Habitability. arXiv:1904.01062. In a paper to appear in Astronomy & Astrophysics, University of Belgrade astronomers VD, Branislav Vukotic and Milan Cirkovic continue to advance technical evaluations of how relatively conducive for life, organisms and persons this Milky Way galaxy might be. To do so, a fine line is drawn between colonization and catastrophe with regard to potential abilities to spread an interstellar civilization or succumb to external or internal disasters. And again it is amazing that a fledgling global prodigy, in this case from a recent war zone, can yet commence such quantifications of celestial frontiers.

Astrobiological evolution of the Milky Way has emerged as one of the key research topics in recent years. In order to build precise, quantitative models of the Galactic habitability, we need to account for two opposing tendencies of life and intelligence in the most general sense: the tendency to spread to all available ecological niches and the tendency to succumb to various types of existential catastrophes. These evolutionary tendencies are being engaged in fields such as ecology, macroevolution, risk analysis, and futures studies, while an astrobiological treatment has been lacking so far. Our aim is to investigate the dynamics of opposed processes of expansion and extinction of life in the Galaxy. While most of the examined parameter space shows very low habitability values, as expected, the remaining part has features that imply a reduction in the amount of fine-tuning to resolve the Fermi paradox. (Abstract excerpts)

Eggl, Siegfried, et al. Habitable Zones in Binary Star Systems: A Zoology. Galaxies. 8/3, 2020. SE, University of Washington, Nikolaos Georgakarakos, NYU Abu Dhabi, and Elke Pilat-Lohinger, University of Vienna astrophysicists provide a latest technical survey of the relative habitability for binary and multiple stellar arrays, which are now seen to compose 40 - 45% of solar objects. Under favorable conditions, living systems will occur and form, but a long term stability vital to evolutionary developments is chancy and unlikely. See also Fear the Shadows of the Giants: On Secular Perturbations in Circumstellar Habitable Zones of Double Stars by Akos Bazso and Elke Pilat-Lohinger at arXiv:2008.11651 (second quote).

Several concepts have been brought forward to determine where terrestrial planets are likely to remain habitable in multi-stellar environments. Dynamically informed habitable zones include gravitational perturbations on planetary orbits, and full scale, self consistent simulations promise detailed insights into the evolution of select terrestrial worlds. Predictions on where to look for habitable worlds in such environments can differ between concepts. The aim of this article is to provide an overview of current approaches and estimates for the various types of habitable zones in binary star systems. (Eggl Abstract)

Results from earlier investigations of binary star systems assumed that well-separated binaries can be simply treated as single star systems. Our new results shed a different light, they demonstrate that secular perturbations do affect the HZ for a wide range of binary system orbital and physical parameters. Passing stars can affect planetary systems severely and can lead to direct or indirect ejections. They explain the apparent overabundance of eccentric (circumstellar) exoplanets in wide binary systems by the action of galactic tides that lead to an increase of the secondary star’s eccentricity, (2008.1165, 37).

Emspak, Jesse. New Insights into How the Solar System Formed. Astronomy. May, 2018. As the quote says, a science writer explains how the latest results increasingly imply that our home incubator is a uniquely conducive milieu. While myriad stellar systems are usually beset with chaos, here our large, gaseous Jupiter appears to have uniquely coursed over billions of years inward and out to form the relatively benign, orderly array that Earth presently abides in.

2018. As the quote says, a science writer explains how the latest results increasingly imply that our home incubator is a uniquely conducive milieu. While myriad stellar systems are usually beset with chaos, here our large, gaseous Jupiter appears to have uniquely coursed over billions of years inward and out to form the relatively benign, orderly array that Earth presently abides in.

Erdmann, Weronika, et al. How the Geomagnetic Field Influences Life on Earth. Origins of Life and Evolution of Biospheres. 51/231, 2021. Adam Mickiewicz University, Poland, biophysicists cite and quantify still another global and celestial factor which could have had a significant influence on life’s evolutionary course.

Earth is a rarity the Solar System because it has an oxidizing atmosphere, moderate temperatures, and a constant geomagnetic field (GMF). The GMF also protects life against the solar wind and cosmic rays which then led to stable environmental conditions. Organisms from archaea to plants and animals may have used the GMF as a source of spatial information. This review thus covers the latest findings about these many influences. In conclusion, a conducive GMF has a positive impact on living organisms, while a weak GMF has a negative affect. (Article excerpt)

Foley, Bradford and Peter Driscoli. Whole Planet Coupling Between Climate, Mantle, and Core. arXiv: 1711.06801. Akin to solar systems being found to act in a coordinated manner, Carnegie Institute for Science geophysicists describe globally dynamic interactions between interior, surface and atmospheric phases, whence an integral bioworld acts as a unitary entity. As a result, another finely choreographed synchrony is required so as to achieve long-term evolutionary habitability.

Earth's climate, mantle, and core interact over geologic timescales. Climate influences whether plate tectonics can take place on a planet, with cool climates being favorable for plate tectonics because they enhance stresses in the lithosphere, suppress plate boundary annealing, and promote hydration and weakening of the lithosphere. Coupling between climate, mantle, and core can potentially explain the divergent evolution of Earth and Venus. As Venus lies too close to the sun for liquid water to exist, there is no long-term carbon cycle and thus an extremely hot climate. On planets within the habitable zone where liquid water is possible, a wide range of evolutionary scenarios can take place depending on initial atmospheric composition, bulk volatile content, or the timing of when plate tectonics initiates, among other factors. Many of these evolutionary trajectories would render the planet uninhabitable. (Abstract)

Forgan, Duncan, et al. Evaluating Galactic Habitability Using High-Resolution Cosmological Simulations of Galaxy Formation. International Journal of Astrobiology. Online January, 2016. Astroscientists Forgan, with Pratika Dayal, Charles Cockell, and Noam Libeskind, proceed as Earthlings to seek out effective ways to estimate the relative kinds, areas, and phases of galaxies which might be favorable for living systems to form and evolve.

Forget, Francois. On the Probability of Habitable Planets. International Journal of Astrobiology. 12/3, 2013. With the rush of Kepler satellite discoveries of a Milky Way and universe filled with solar systems and orbital objects of every kind, the prevalence, or absence, of earth-analog bioworlds has become a prime issue. An Institute Pierre Simon Laplace, Universite Paris, astrophysicist here provides a succinct technical survey. Four classes of conducive worlds are cited: Planets like this with suitable water, atmosphere, and stabilities; Earth-like but unable to hold aqueous seas; Worlds with too much water and/or geothermal activity; and Ice covered, frozen globes. A suggestive allusion as made by Paul Davies, John Gribbin and others, is that in some real way our minute, self-regulating orb just flickering into knowing consciousness may be of immense significance after all.

In the past 15 years, astronomers have revealed that a significant fraction of the stars should harbor planets and that it is likely that terrestrial planets are abundant in our galaxy. Among these planets, how many are habitable, i.e. suitable for life and its evolution? Liquid water remains the key criterion for habitability. It can exist in the interior of a variety of planetary bodies, but it is usually assumed that liquid water at the surface interacting with rocks and light is necessary for the emergence of a life able to modify its environment and evolve. A first key issue is thus to understand the climatic conditions allowing surface liquid water assuming a suitable atmosphere. This have been studied with global mean 1D models which has defined the “classical habitable zone”, the range of orbital distances within which worlds can maintain liquid water on their surfaces. A new generation of 3D climate models based on universal equations and tested on bodies in the solar system is now available to explore with accuracy climate regimes that could locally allow liquid water. A second key issue is now to better understand the processes which control the composition and the evolution of the atmospheres of exoplanets, and in particular the geophysical feedbacks that seems to be necessary to maintain a continuously habitable climate. From that point of view, it is not impossible that the Earth’s case may be special and uncommon. (Abstract)

Frank, Adam. Light of the Stars: Alien Worlds and the Fate of the Earth. New York: Norton, 2019. The University of Rochester astrophysicist and author (search UR) provides a latest survey of the 2ist century revolutionary witness of an innately planet and solar system making cosmos, which begets living systems and a global sapience able to learn this. The unique work is an insider’s view of profligate biospheres and maybe noospheres, citing Vernadsky, Teilhard, Lovelock and Lynn Margulis, which infer a growing sense of an inherent astrobiology. But these findings lead us to realize that our Anthropocene moment is due to many rare, favorable twists and turns along the way.

Adam Frank then coins a phrase “thinking like a planet” which we should aspire to and put into practice. If a relative significance to the whole galactic cosmos might rightly be appreciated for our habitable abide with rising perils, it could provide a unifying incentive we so need. It is alluded that if a sustainable bioworld is achieved, we Earthlings can become “winners in the game of cosmic evolution.” The innovative idea was indeed availed by David Wallace-Wells in The Uninhabitable Earth in a closing section The Anthropic Principle.

From this perspective, civilizations become just another thing the Universe does, like solar flares or comets. We can use what the stars have laid out before us in our astrobiological studies to explore how any civilization on any planet can – or, in the worst case, cannot – evolve together. The advantages of this astrobiological perspective can be gained even if no other civilization ever existed. Thinking about hypothetical exo-civilizations is valuable in dealing with the challenge of the Anthropocene because it reaches us to “think like a planet.” It teaches us to frame our pathways to a long-term project of civilization in terms of the coevolution between life and the Earth. (15)

Frank, Adam and Woodruff Sullivan. A New Empirical Constraint on the Prevalence of Technological Species in the Universe. arXiv:1510.08837. The University of Rochester and University of Washington astronomers update the Drake equation (search Vakoch) by way of the latest rush of satellite exoplanet findings to boost chances that our prodigious planet is not alone. See also A Population-Based Habitable Zone Perspective by Andras Zsom at arXiv:1510.06885.

In this paper we address the cosmic frequency of technological species. Recent advances in exoplanet studies provide strong constraints on all astrophysical terms in the Drake Equation. Using these and modifying the form and intent of the Drake equation we show that we can set a firm lower bound on the probability that one or more additional technological species have evolved anywhere and at any time in the history of the observable Universe. We find that as long as the probability that a habitable zone planet develops a technological species is larger than ~10−24, then humanity is not the only time technological intelligence has evolved. This constraint has important scientific and philosophical consequences. (Abstract)

Frank, Adam and Woodruff Sullivan. Sustainability and the Astrobiological Perspective: Framing Human Futures in a Planetary Context. arXiv:1310.3851. University of Rochester and University of Washington astrophysicists embellish the vista proposed by Arnould, Baum, and Naganuma herein that it well serves to situate our precious Earth in its fertile galactic milieu. Circa 2013, a prominent addition is the discovery of myriad extrasolar planets and widening solar habitable zones. In our Anthropocene era, only a cosmic perspective can provide both the ecosphere systems purview, and the import of an intelligent, healthy bioworld to the greater creation.

We explore how questions related to developing a sustainable human civilization can be cast in terms of astrobiology. In particular we show how ongoing astrobiological studies of the coupled relationship between life, planets and their co-evolution can inform new perspectives and direct new studies in sustainability science. Using the Drake Equation as a vehicle to explore the gamut of astrobiology, we focus on its most import factor for sustainability: the mean lifetime of an ensemble of Species with Energy-Intensive Technology (SWEIT). We then cast the problem into the language of dynamical system theory and introduce the concept of a trajectory bundle for SWEIT evolution and discuss how astrobiological results usefully inform the creation of dynamical equations, their constraints and initial conditions. Three specific examples of how astrobiological considerations can be folded into discussions of sustainability are discussed: (1) concepts of planetary habitability, (2) mass extinctions and their possible relation to the current, so-called Anthropocene epoch, and (3) today's changes in atmospheric chemistry (and the climate change it entails) in the context of pervious epochs of biosphere-driven atmospheric and climate alteration (i.e. the Great Oxidation Event). (Abstract)

Fremont, Emeline, et al.. Atmospheric Escape From Three Terrestrial Planets in the L 98-59 System. arXiv:2312.00062. As studies of orbital exoworld studies become ever more sophisticated, nine astroscientists at the University of Maryland, NASA Goddard, Universidad Nacional Autonoma de Mexico, University of Washington, and Jet Propulsion Laboratory are now able to quantify the presence or evaporative absence of atmospheric conditions, which then have a major effect on habitability. Once again, over long durations the situation has a stochastic aspect, such as relative location to a host star.

A critically important process affecting the climate evolution and potential habitability of an exoplanet is atmospheric escape, in which high-energy radiation from a star drives the escape of hydrogen atoms and other light elements. L 98-59 is a benchmark system for studying this occasion, such as water loss and oxygen loss. Our results constrain the atmospheric evolution of these small rocky planets, and they provide context for current and future observations of the L 98-59 system to generalize our understanding of multi-terrestrial planet systems. (Excerpt)

Further, the presence of an atmosphere on any of the L 98-59 planets is highly dependent on the way the planets evolved in the presence of their star’s stellar activity. Therefore, our work studying the effects of flares and strong XUV radiation on volatile loss or accumulation for these planets may help us to better constrain certain characteristics of the system, such as stellar age, initial planetary composition, and planetary formation processes, in future JWST observations.

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