III. Ecosmos: A Revolutionary Fertile, Habitable, Solar-Bioplanet Incubator Lifescape
I. Our EarthMost Occasion: A Rarest Confluence of Favorable Features and Close Calls
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.
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.
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)
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)
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)
Mathews, Freya. Moral Ambiguities in the Politics of Climate Change. Nanda, Ved, ed.. Climate Change and Environmental Ethics. New Brunswick, NJ: Transaction Publishers, 2011. Two decades after her visionary The Ecological Self work about individual and cosmic self-realization (search), the Australian ecophilosopher continues to meld “anthropocentric and biocentric” options in a viable, creative synthesis. Along with the quotes, she advises a “bio-synergy,” a “relational inter-functionality” of persons and planet, little self and Big self, as each engaged in a deep process of psychic individuation.
I would like to propose two ways – both holistic, but differently so – in which “nature” under its global aspect might be conceived. The first such way in which nature might be conceived is as a self-realizing or autopoetic system, defined not in terms of the elements that contingently constitute it, but in terms of its ends as an entity in its own right, which is to say, in terms of its status as an end-for-itself, and its disposition to navigate circumstances in such a way as to preserve its own identity as a living system through time and change. (48)
McIntyre, Sarah, et al. Planetary Magnetism as a Parameter in Exoplanet Habitability. arXiv:1903.03123. Australian National University astrophysics including Charles Lineweaver proceed to add another physical, geologic factor which could influence whether a globular, orbital object might harbor living systems and an evolutionary intelligence. As the abstract says, a certain range of values are required to maintain conducive watery and airy conditions.
Evidence from the solar system suggests that, unlike Venus and Mars, the presence of a strong magnetic dipole moment on Earth has helped maintain liquid water on its surface. Therefore, planetary magnetism could have a significant effect on the long-term maintenance of atmosphere and liquid water on rocky exoplanets. We use Olson and Christensen's (2006) model to estimate magnetic dipole moments of rocky exoplanets with radii Rp ≤ 1.23 R⊕. Even when modelling maximum magnetic dipole moments, only Kepler-186 f has a magnetic dipole moment larger than the Earth's, while approximately half of rocky exoplanets detected in the circumstellar habitable zone have a negligible magnetic dipole moment. This suggests that planetary magnetism is an important factor when prioritizing observations of potentially habitable planets. (Abstract)
Milner, Yuri. Are We Alone?. www.breakthroughinitiatives.org/AreWeAlone. On a site for the Breakthrough Initiatives project launched and funded by the Russian entrepreneur, and physicist, this page exhorts that in a galactic cosmos now known to be filled with habitable planets, it is of ultimate import whether our precious bioworld is uniquely aware, or do we have myriad neighbors. It is endorsed by many luminaries such as Stephen Hawking, Martin Rees, Jill Tarter, Nikolay Kardashev, Sara Seager, and Kip Thorne. Another endeavor is Breakthrough Starshot, more below, to scope out and initiate the sending of probes to Alpha Centuri, the closest star to our sun. The announcement was on the nightly news, and in the NY Times for April 12, 2016 as Reaching for the Stars, Across 4.37 Light-Years by Dennis Overbye.
Who are we? A mature civilization, like a mature individual, must ask itself this question. Is humanity defined by its divisions, its problems, its passing needs and trends? Or do we have a shared face, turned outward to the Universe? Because the biggest questions of our existence are at stake. Are we the Universe’s only child - our thoughts its only thoughts? Or do we have cosmic siblings - an interstellar family of intelligence? There are likely billions of earth-like worlds in our galaxy alone. And with instruments now or soon available, we have a chance of finding out if any of these planets are true Pale Blue Dots – home to water, life, even minds.
Milojevic, I. and S. Inayatullah. Futures Dreaming Outside and on the Margins of the Western World. Futures. 35/5, 2003. An argument that the vast genre of science fiction is largely written by white males who are preoccupied with war between binary opposites. Non-western, indigenous writers, especially women, are noted to be in search of alternative, less-combatant, holistically peaceful and creative visions.