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

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

Lammer, Helmet, et al. The Role of Nitrogen as a GeoBiosignature for the Detection and Characterization of Earth-like Habitats. arXiv:1904.11716. A seven member group mainly from the Austrian Academy of Sciences Space Research Institute cites that the appropriate presence of this globally atmospheric and chemical element ought to be seen as another important factor for life’s emergent evolution.

Since the Archean, nitrogen has been a major atmospheric constituent in Earth's atmosphere. It is an essential element in the building blocks of life, therefore the geobiological nitrogen cycle is a fundamental factor in the long term evolution of both Earth and Earth-like exoplanets. We discuss the development of the Earth's N2 atmosphere since the planet's formation and its relation with the geobiological cycle. Then we suggest atmospheric evolution scenarios and their possible interaction with life forms for a stagnant-lid anoxic world, a tectonically active anoxic world, and an oxidized tectonically active world. Since life forms are the most efficient means for recycling deposited nitrogen back into the atmosphere nowadays, they sustain its surface partial pressure at high levels. (Abstract excerpt)

Lineweaver, Charles and Molly Townes O’Brien. The Cosmic Context of the Millennium Development Goals: Maximum Entropy and Sustainability. Thomas Faunce, ed. Nanotechnology Toward the Sustainocene. Singapore: Pan Stanford Publishing, 2015. An Australian National University astronomer and law professor expansively situate our crucial imperative to achieve a better populace and planet within a widest temporal and spatial evolutionary locus. In this whole scenario, a global transition to organic viability would contribute to the arrow and advance of informed, personified order over disorderly dissipations.

Life forms are a subset of the organized structures in the universe known as far-from equilibrium dissipative systems (FarFEDS). FarFEDS are dissipative structures that, while maintaining their structure, convert low-entropy energy to high-entropy energy. They include galaxies, stars, convection cells, typhoons, fires, humans, and bacteria. All FarFEDS (and thus all life forms) extract free energy from the environment and turn it into waste heat faster than random processes such as diffusion would be able to do. (41-42)

Lingam, Manasvi. Implications of Abiotic Oxygen Buildup for Earth-like Complex Life. arXiv:2002.03248. A Florida Institute of Technology astrophysicist (search) surveys the importance for a bioworld to achieve a favorable atmospheric O2 level in the low 20% range for life to be able to develop and evolve. This small window between starved and burnt up need be reached in a timely way (Lineweaver) and persist over relatively long periods. This atmospheric quality would then be a vital biosignature. See also Ward, Lewis, et al. Follow the Oxygen: Comparative Histories of Planetary Oxygenation and Opportunities for Aerobic Life by Lewis Ward, et al in Astrobiology (19/6, 2019). In regard, still another vital, finely tuned check point to successfully pass through is highlighted.

One of the chief paradoxes of molecular oxygen (O2) is that it is an essential requirement for multicellular eukaryotes on Earth while simultaneously posing a threat to their survival via the formation of reactive oxygen species. In this paper, the constraints imposed by O2 on Earth-like complex life are applied to whether worlds with abiotic O2 inventories can harbor such organisms. By consideration of the O2 sources and sinks of Earth-like planets, it is proposed that worlds with X-ray and extreme ultraviolet fluxes might not host complex lifeforms because the photolysis of water molecules may cause high O2 buildup. (Abstract excerpt)

Lingam, Manasvi and Abraham Loeb. Dependence of Biological Activity on the Surface Water Fraction of Planets. arXiv:1809.09118. The Harvard University, Institute for Theory and Computation postdoc and director team (search) continue their studies of extraterrestrial life by noting a critically vital feature of this habitable Earth, namely a 30% land and 70% ocean ratio maintained over some three billion years. As such multiphase exoplanet research proceeds apace, it is becoming evident that this dual division is a rarest state. The common spherical default is wholly dry, watery or gaseous. Plate tectonic movements are then seen to add a significant favorable condition (still going on in the Pacific rim of fire). A previous entry (L & L, 1804.02271) considered the effect of stellar physics on planetary life. As this section seeks to report, our home sapient Earth seems to be an increasingly special bioplanet amongst myriad vicarious candidates. This is an awesome, unexpected finding in need of much public report and notice, at a same time when nuclear nations are in headlong regression.

One of the unique features associated with the Earth is that the fraction of its surface covered by land is comparable to that spanned by its oceans and other water bodies. Here, we investigate how extraterrestrial biospheres depend on the ratio of the surficial land and water fractions. We find that worlds that are overwhelmingly dominated by landmasses or oceans are likely to have sparse biospheres. Our analysis suggests that major evolutionary events such as the buildup of O2 in the atmosphere and the emergence of technological intelligence might be relatively feasible only on a small subset of worlds with surface water fractions ranging approximately between 30% and 90%. We also discuss how our predictions can be evaluated by future observations, and the implications for the prevalence of microbial and technological species in the Universe. (Abstract)

The paper is organized as follows. In Sec. 2, we examine the biological potential of extraterrestrial biospheres and discuss the consequences for the buildup of O2 in the atmosphere. In Sec. 3, we discuss how the emergence of technological intelligence may depend on the surficial land-water ratio of these worlds. We follow this up with a discussion of how common are worlds with surface landmasses and oceans in Sec. 4. (2)

The emergence of technological intelligence turned out to be very sensitive to the size of the world, i.e. larger worlds are endowed with a significant advantage. For Earth-sized worlds, a water fraction of 30-90% might ensure that the likelihood of technological intelligence relative to the Earth is reasonably high. We also found that the Earth’s value of δw (ratio of land to water) appears to be close to the optimum with respect to the emergence of technological species. (10)

Lingam, Manasvi and Abraham Loeb. Implications of Tides for Life on Exoplanets. arXiv:1707.04594. Harvard-Smithsonian Center for Astrophysics theorists consider this geospheric surface condition which could have a major influence on long-term habitability. Our own Earth-moon system is an optimum situation of moderate tidal flows and basins, whereof cellular life can begin its evolutionary course. However, on the many other exoworlds just being found, this stable state maybe a rare occurrence. A corollary or default phase has become known “tidal locking” whence an orbiting object enters a tandem rotation with a host star or moon, see Tidal Locking of Habitable Exoplanets by Rory Barnes herein.

As evident from the nearby examples of Proxima Centauri and TRAPPIST-1, Earth-sized planets in the habitable zone of low-mass stars are common. Here, we focus on such planetary systems and argue that their (oceanic) tides could be more prominent due to stronger tidal forces. We identify the conditions under which tides may exert a significant positive influence on biotic processes including abiogenesis, biological rhythms, nutrient upwelling and stimulating photosynthesis. We conclude our analysis with the identification of large-scale algal blooms as potential temporal biosignatures in reflectance light curves that can arise indirectly as a consequence of strong tidal forces. (Abstract)

Lingam, Manasvi and Abraham Loeb. Physical Constraints for the Evolution of Life on Exoplanets. arXiv:1810:02007. Some two weeks after a posting (1809.09118, see also 1807.08879, 1804.02271) about how plate tectonics can effect habitability, this Harvard team, funded in part by the Breakthrough Foundation, here view additional vicarious cosmic, solar, and geologic influences such as stellar coronal winds and flares, planetary magnetospheres, oceanic and atmospheric evaporations, electromagnetic radiation, relative oxygen buildup, origins of life, photosynthesis, and more in mathematic detail. These studies are then supported with some 300 references. Once again, this home Earth whereupon a sapient species is altogether able to explore, quantify and learn, seems to be an increasingly unique candidate personsphere.

Some two weeks after a posting (1809.09118, see also 1807.08879, 1804.02271) about how plate tectonics can effect habitability, this Harvard team, funded in part by the Breakthrough Foundation, here view additional vicarious cosmic, solar, and geologic influences such as stellar coronal winds and flares, planetary magnetospheres, oceanic and atmospheric evaporations, electromagnetic radiation, relative oxygen buildup, origins of life, photosynthesis, and more in mathematic detail. These studies are then supported with some 300 references. Once again, this home Earth whereupon a sapient species is altogether able to explore, quantify and learn, seems to be an increasingly unique candidate personsphere.

Lingam, Manasvi and Abraham Loeb. Role of Stellar Physics in Regulating the Critical Steps for Life. arXiv:1804.02271. Harvard University, Institute for Theory and Computation (see below), astrophysicists (postdoc and director) enter a 34 page, 200 reference paper as much about how the major evolutionary transitions scale (see Szathmary, Section VI. H. 8) is a good guide to the active quest for exoplanetary life and mind. Here five main stages of Prokaryotes, Eukaryotes, Plastids (organelles), Complex Multicellularity, and Human Persons (homo sapiens) are proposed, with Oxygenic photosynthesis, land invasion, and technological intelligence as subsets. By this view, an “extended habitability” zone is drawn for Earth of a prior 4.5 billion past years (Gyr), and 1-2 Gyr ahead.

With this sketch in place, the effects of solar type (our sun is a G yellow dwarf), variable radiative intensities, and other stellar aspects, are considered with regard to original, primitive biochemical, unicell phases and their evolution all the way to technical civilizations. It is then noted that while teleological progress is out of favor, this well researched, episodic course from primal microbes to literate peoples does trace an oriented ascent. And if to wonder about it all in 2018, a worldwide humankinder seems well on her/his way to an organic, procreative ecosmos, stochastic to be sure, which fills itself with potentially habitable bioworlds and embryogeneses toward salutary self-discovery.

We us the critical step model to study the major transitions in evolution on Earth. We find that a total of five steps represents the most plausible estimate, in agreement with previous studies, and use the fossil record to identify the potential candidates. We apply the model to Earth-analogs around stars of different masses by incorporating the constraints on habitability set by stellar physics including the habitable zone lifetime, availability of ultraviolet radiation for prebiotic chemistry, and atmospheric escape. The critical step model suggests that the habitability of Earth-analogs around M-dwarfs is significantly suppressed. The total number of stars with planets containing detectable biosignatures of microbial life is expected to be highest for K-dwarfs. In contrast, we find that the corresponding value for intelligent life (technosignatures) should be highest for solar-mass stars. Thus, our work may assist in the identification of suitable targets in the search for biosignatures and technosignatures. (Abstract)

Harvard University Institute for Theory and Computation The mission of the ITC is to advance our knowledge and understanding of the universe through computational and analytical means, to create a forum for exploration and discoveries in theoretical astrophysics, and to train the next generation of astrophysicists. ITC addresses a wide variety of problems such as simulations of galaxy formation in the Universe, large scale structure in the universe, accretion of gas onto black holes, the first stars & black holes and the search for life and planet formation.

Livingston, John. One Cosmic Instant. Boston: Houghton Mifflin, 1973. Some 35 years ago the York University environmentalist placed earth’s increasing ecological stress, evident even then, in the long perspective of a special bioplanet whose life evolves to human technological sentience, only to place itself at terminal peril. Today it is often said that we have already overshot a global carrying capacity, that earth has a fever, temperature unknown, that its physiology can in fact perish. By this view, we have indeed reached a second singularity which requires our mindful self-selection.

Livio, Mario. How Special is the Solar System?. arXiv:1801.05061. The veteran Romanian, Israeli, American astrophysicist and author (search) posts a chapter to appear in Consolidation of Fine-Tuning, see Anthropic Principle for website. Livio also has a joint chapter with Martin Rees about the multiverse, noted herein. To wit, an array of unusual features such as a quiet, stable sun, orderly planetary orbits and spacings, and more do allude to a rare cocatenation. While early and speculative, there is something curious about our home Earth-Sun nexus, as a sentient species begins to wonder about it all.

Given the fact that Earth is so far the only place in the Milky Way galaxy known to harbor life, the question arises of whether the solar system is in any way special. To address this question, I compare the solar system to the many recently discovered exoplanetary systems. I identify two main features that appear to distinguish the solar system from the majority of other systems: (i) the lack of super-Earths, (ii) the absence of close-in planets. I examine models for the formation of super-Earths, as well as models for the evolution of asteroid belts, the rate of asteroid impacts on Earth, and of snow lines, all of which may have some implications for the emergence and evolution of life on a terrestrial planet. (Abstract)

An examination of the physical properties of our solar system reveals that it is not extremely unusual when those are compared to the characteristics of the other observed exoplanetary systems. Still, there is no doubt that a few of the solar system’s parameters have made it conducive to the emergence and evolution of life. For example, low eccentricity planets (as observed in the solar system) have a more stable temperature throughout the entire orbit, which may make them more likely to harbor life [123]. Planetary systems with a low mean eccentricity are also more likely to have a long-term dynamical stability. (32)

Macdonald, Evelyn, et al. Climate Uncertainties Caused by Unknown Land Distribution on Habitable M-Earths. arXiv:2110.04310. (M-Earth denotes an exoplanet with a Mass similar to our own) University of Toronto astrophysicists find the wide range of possible land and ocean ratios, as they vary over time, to contribute still another contingent factor with regard to the presence of living, evolutionary systems.

A planet's surface conditions can significantly impact its environmental habitability. In this study, we use the 3D general circulation model ExoPlaSim to vary dayside land cover on a rotating, temperate rocky planet under two opposite continent extremes whence all the land or all the ocean is centred at the substellar point. We identify water vapour and sea ice as climate drivers, and isolate land-dependent regimes under which case rules. We find that the amount and configuration of land can change a planet’s average surface temperature by up to 20K, and its atmospheric water content by orders of magnitude. (Abstract excerpt)

Martin, David. Populations of Planets in Multiple Star Systems. arXiv:1802.08693. In a chapter for the Handbook of Exoplanets (September 2018), a Swiss National Science Foundation Fellow at the University of Chicago gathers latest findings that find orbital worlds in a vicinity of two or more suns with as fairly common, maybe up to half of galactic cases. The situation is seen as an exotic example of nature’s ubiquitous diversity. It is then generally surmised that such a chaotic solar and planetary arrangements are not favorable, indeed ruinous, for long life term habitability.

Martin, Rebecca and Mario Livio. Asteroids and Life: How Special is the Solar System?. arXiv:2202.01352. University of Nevada cosmobiologists consider still another celestial anomaly which may have played a part in the occasion and course of life’s evolutionary development. As the Abstract notes, our collaborative sapiensphere continues to quantify parameters which could have affected relative environmental conditions. In this case, a certain amount of meteoric contacts seems to be a vital gradient.

Asteroid impacts with the Earth may have played an essential role in the emergence of life through their creation of favorable niches, favorable atmospheres and the delivery of water. Consequently, we suggest two potential requirements for exoplanetary life: first, that the system has an asteroid belt, and second, a mechanism to drive asteroids to impact the exoterrestrial habitable planet. Since in the solar system, the ν6 secular resonance is involved in driving these impacts, we explore how the giant planets affect this property. Hence the solar system is somewhat special, but the degree of fine-tuning that may be necessary for the emergence of life is not excessive. (Abstract)

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