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

I. Our EarthMost Occasion: A Rarest Confluence of Favorable Features and Close Calls

Naganuma, Takeshi. An Astrobiological View on Sustainable Life. Sustainability. 1/4, 2009. A Hiroshima University, Graduate School of Biosphere Science, environmentalist, who could not be in a more appropriate place, imaginatively views matter, evolution and its human frontier as a vectorial vortex of thermodynamic energies. In regard, it is asked whether such knowledge from its collective humankind scale can come to a common fore to save and sustain us.

In the Japanese language, the Sun is hi, and heat (fire) is also hi (originally ho or fo); water is mi or mizu; and, life is i-no-chi meaning energy of breath. The coincidence of two hi has impressed me, and I might say that split of mi by hi nourishes chi, at least, on the Earth. Both hi, that is the Sun’s radiation and the Earth’s interior heat, contribute to life. The degrees of contributions vary according to major modes of autotrophy, i.e., photosynthesis or chemolithoautotrophy. Examples of chemolithoautotrophic communities that depend primarily on geothermal hi are found in deep-sea hydrothermal vents and deep subsurface, respectively [4,5]. The idea that non-solar splitting of water nourishes life thus derives from the studies of deep-sea and deep subsurface biospheres, and is extended to possible extra-terrestrial biospheres. The concept of planetary biospheres should accommodate a more universal notion of life than traditional ones. The “non-solar splitting of water” idea is applicable to possible astrobiological biospheres. (835-836)

O'Callaghan, Jonathan. A Solution to the Faint-Sun Paradox Reveals a Narrow Window for Life. Quanta Magazine. January 27, 2022. A science writer describes a latest quandary which seems to affect the relative habitability of our Earth, and exoworlds. A fine temperature confluence between a steady solar source and crustal living systems need exist and be sustained for any evolutionary course to succeed. See also Chance Played a Role in Determining Whether Earth Stayed Habitable by Toby Tyrrell in Communications Earth & Environment (1/61, 2020).

We know that life under our faint young sun was possible, and now we might know why. What we are starting to see is just how lucky we may have been in avoiding becoming a permanent snowball Earth or even a steam Earth. Somehow, conditions were just right on our planet, keeping us in this narrow window between being frozen solid and evaporating to oblivion, and allowing us to survive — despite a few near misses. “There’s a huge discussion about the requirements for habitability,” said Georg Feulner. “Even on Earth, things could have gone wrong easily.” (13)

Olse,, Stephanie, et al. The Effect of Ocean Salinity on Climate and its Implications for Earth’s Habitability. arXiv:2205.06785. As if we didn’t need any more fine-tuned conditions, Purdue University, University of Chicago, Weizmann Institute of Sciences and University of Victoria researchers including Dorion Abbot note that variable salt water levels could have aid or inhibit life’s planetary occasion and course.

The influence of atmospheric composition on the climates of present-day and early Earth has been studied extensively, but the role of ocean composition has received less attention. We use the ROCKE-3D ocean-atmosphere general circulation model to investigate the response of Earth's present-day and Archean climate system to low vs. high ocean salinity. We find that saltier oceans yield warmer climates due to changes in ocean dynamics. In combination with higher levels of greenhouse gases such as CO2 and CH4, a saltier ocean may allow for a warm Archean Earth with only seasonal ice at the poles despite receiving 20% less energy from the Sun. (Abstract)

Olson, Stephanie, et al. Oceanographic Constraints on Exoplanet Life. arXiv:1909.02928. With our favorable tectonic balance of land and sea as a reference, University of Chicago geophysicists including Dorian Abbot consider variable exoworld oceanic conditions with regard to the presence of living systems. This liquid, amniotic surface hydrosphere is also seen as a major factor in their relative biological detectability. See also Scaling Relations for Terrestrial Exoplanet Atmospheres from Baroclinic Criticality by this extended group at 1908.02661 for more vital properties.

Liquid water oceans are crucial to our search for life on exoplanets because water is essential for life as we know it. However, oceans are dynamic habitats and some may be better hosts for life than others. In Earth's oceanic circulation conveys nutrients such as phospourous which affects the distribution and productivity of life. Of importance is upwelling due to wind-driven divergence in surface layers, which returns nutrients that tend to accumulate at depth. We address these aspects by using ROCKE-3D, a fully coupled ocean-atmosphere GCM, to investigate ocean dynamics on a diversity of habitable planets. Efficient nutrient recycling favors greater biological activity for better biosignature detection. Our results demonstrate the importance of oceanographic phenomena for exoplanet life detection and the emerging field of exo-oceanography. (Abstract excerpt)

Pacetti,, Elenia, et al. The Impact of Tidal Disruption Events on Galactic Habitability. arXiv:2008.09988. University of Rome and Florida Institute of Technology astroresearchers including Amedeo Balbi and Manasvi Lingam add another impediment to planetary habitations by pointing out that perilous radiations which seem to suffuse far interstellar reaches will be deleterious in various ways to living systems. See also The Habitability of the Galactic Bulge at 2008.07586.

Tidal Disruption Events (TDEs) are characterized by the emission of a short burst of high-energy radiation. We analyze the cumulative impact of TDEs on galactic habitability using the Milky Way as a proxy. We show that X-rays and extreme ultraviolet (XUV) radiation emitted during TDEs can cause hydrodynamic escape and instigate biological damage. In particular, we show that planets within distances of ∼0.1-1 kpc could lose Earth-like atmospheres over the age of the Earth. We conclude by highlighting potential ramifications of TDEs and argue that they should be factored into analyses of inner galactic habitability. (Abstract)

To summarize, two broad conclusions emerge from this work. First, the cumulative negative impact of TDEs on habitability is comparable to that of Active Galactic Nuclei. Second, some fraction of planetary systems closer to the central black hole of the Milky Way may have been adversely affected. Our analysis suggests that TDEs might exert a substantive influence on planetary habitability. (5)

Panov, Alexander. Post-Singular Evolution and Post-Singular Civilizations. Grinin, Leonid, et al, eds. Evolution: A Big History Perspective. Volgograd: Uchitel Publishing, 2011. While not citing Ray Kurzweil’s technological version, within this evolutionary cosmos a Moscow State University physicist philosopher cites a central, transformative event, a “global biospheric revolution,” whence planetary life might finally rise and awaken to a consummate intelligence. At this ultimate moment, a worldwise civilization need be able to proactively achieve a common knowledge, mindfulness and peaceable allegiance to reign in machines and weaponry. If this half-way point can be successfully passed through, a second phase of a creative “Exo-humanism” future spreading across galaxy and cosmos can commence. See also in this volume The Noospheric Concept of Evolution, Globalization and Big History by Vasily Vasilenko.

It is shown that the ability of the world civilization to overcome a singularity border (a system crisis) determines some important civilization's feature in an intensive post-singular phase of development. A number of features of the post-singular civilization can stimulate its ‘strong communicativeness’, which is a prerequisite for the formation of ‘the galactic cultural field’. Post-singular civilizations – carriers of the cultural field – are considered as potential partners in interstellar communication and as our own potential future. (Abstract)

We proposed the scenario of post-singular evolution in which the leadership system is a post-singular civilization in intensive phase of development. A post-singular civilization is exo-humanistic and exo-humanitarian, one that is part of the galactic cultural field. The typical features of an exo-humanitarian civilization must be moral imperatives of exo-humanism and, apparently, a declining state of investigations with the classical scientific method, at least in the field of fundamental sciences. Such a civilization is communicative in the strong sense. It would not be overstating the case to say that, when establishing contact with such a civilization, we contact the wider cultural field and become an element of it. (228)

Paradise, Adiv, et al. Climate Diversity in the Habitable Zone due to Varying pN2 Levels. arXiv:1910.02355. As if we did not already have enough finely tuned conditions which serve to make this home habitable Earth so very special, here University of Toronto astrophysicists and a biologist point out that an optimum band and pressure of atmospheric nitrogen is another vital parameter. For our bioplanet, it nominally is 79% and 21% oxygen within a tight zone of a few percent either way. In addition this range which has remained relatively stable for millions of years.

A large number of studies have responded to the growing body of confirmed terrestrial habitable zone exoplanets by presenting models of various possible climates. However, the impact of the partial pressure of gases such as N2 has been poorly-explored, despite the abundance of N2 in Earth's atmosphere. We use PlaSim, a fast 3D climate model, to simulate hundreds of climates with varying N2 pressures, insolations, and surfaces to identify the impact of the gas partial pressure on the climate. We find that the climate's response is nonlinear and highly sensitive to this factor. We identify CO2 and H2O absorption lines, warming or cooling by the water vapor greenhouse positive feedback, heat transport, and more as competing mechanisms that determine the equilibrium climate. (Abstract excerpts)

Pilat-Lohinger, Elke. The Role of Dynamics on the Habitability of an Earth-like Planet. International Journal of Astrobiology. 14/2, 2015. In an Exoplanet issue, a University of Vienna astrophysicist reaches a notable conclusion about our own solar system. It seems especially conducive because the orbital planets all lie in the same plane, and have basically circular orbits. Such a relative stability over a long time period is most favorable for a suitable biosphere upon which life can evolve and emerge to a noosphere able to observe itself and a planetary neighborhood.

Prantzos, Nikos. A Probabilistic Analysis of the Fermi Paradox in Terms of the Drake Formula. arXiv:2003.04802. Two decades after his Our Cosmic Future book, the Institute of Astrophysics, Paris, research director provides a new update of this equation estimate of how many Earth-like worlds might exist. It is also cast another response to Enrico’s 1950s concern that no one actually seems to be there. An underrated factor may have been the lifetime duration of a technical civilization. This would have a major winnowing effect if they could not get their common act together so as to save their home bioworld. Based on our own terminal perils, this situation could imply that a decisive planetary self-realization and selection, indeed a sustainability singularity, is a critical. imperative step. In Prantzos’ expansive view, civilizations are seen to randomly come and go, some for a short period, others may be longer. Earth is not the first, nor the last, but at the present time is alone for these reasons.

In evaluating the number of technological civilizations N in the Galaxy through the Drake formula, emphasis is mostly put on astrophysical and biotechnological factors describing the emergence of a civilization and less on its lifetime L, which is strongly related to its demise. It is argued that this factor is in fact the most important regarding the practical implications of the Drake formula, because it determines the extent of the "sphere of influence" of any technological civilization. The Fermi paradox is then studied by way of a simplified Drake version through Monte Carlo simulations of N civilizations expanding in the Galaxy during their space faring lifetime. In that frame, the probability of "direct contact" is set as the fraction of the Galactic volume occupied collectively by N civilizations. The results are used to find regions in the parameter space where the Fermi paradox holds. (Abstract excerpt)

Provenzale, Murante, et al. Climate Bistability of Earth-like Planets. arXiv:1912.05392. Eleven astroscientists from Torino to Trieste report that our own world seems to have passed through both colder, icy states and warmer, watery times. By these findings, this prior occasion appears as dual climatic options, depending on relative levels of energetic forcings. And as noted, such dynamic shiftings may play a serious role as evolutionary organisms may proceed on their course.

About 500 million years ago, our planet seems to have experienced snowball conditions, with continental and sea ices covering a large fraction of its surface. This situation points to a potential bistability of Earth's climate, that can have at least two equilibrium states for the same external solar radiation forcing. Here we explore the probability of bistable climates in earth-like exoplanets, and the properties of planetary climates obtained by varying the semi-major orbital axis, eccentricity, obliquity, and atmospheric pressure. To this goal, we use the Earth-like surface temperature model (ESTM) to provide a climate estimator for parameter sensitivity and long climatic simulations. An intriguing result of the present work is that the planetary conditions that support climate bistability are remarkably similar to those required for the sustenance of complex, multicellular life on the planetary surface. (Abstract excerpt)

Quarles, Billy, et al. Obliquity Evolution of Circumstellar Planets in Sun-like Stellar Binaries. arXiv:1911.08431. We add this report by Georgia Tech and NASA astronomic researchers including Jack Lissauer because it broaches another vicarious variable which could influence for better or worse life’s chances to evolve and reach global abilities to retrospectively perceive realize this reality.

Changes in planetary obliquity, or axial tilt, influence the climates on Earth-like planets. In the solar system, the Earth's obliquity is stabilized due to our moon which causes small amplitude variations beneficial for advanced life. Most Sun-like stars have at least one stellar companion and the habitability of their exoplanets is shaped by these pairings. We show that a stellar companion dramatically effects whether an Earth-like obliquity stability is possible. We present a new formalism for the planetary spin precession that accounts for orbital misalignments between the planet and binary. Thus, Earth-like planets likely experience much larger obliquity variations, with more extreme climates, unless they are in specific favorable states. (Abstract excerpt)

Ramirez, Rodrigo, et al. New Numerical Determination of Habitablility in the Galaxy. International Journal of Astrobiology. Online March, 2017. Universidad Nacional Autonoma de Mexico and Instituto de Estudios Avanzados de Baja, California astrophysicists finesse quantifications of the relative galactic and cosmic occurrence of planetary life. While rudimentary organisms may likely proliferate, a global evolution of technological civilizations may be less common and hardly detectable.

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