VII. Pedia Sapiens: A Genesis Future on Earth and in the Heavens
C. An Earthropic Principle: Novel Evidence About a Special Planet
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.
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.
Raymond, Sean. Sculpting Our Planetary System. American Scientist. September-October, 2018. In an issue on the many ways that Big Data/AI methods are bringing new capabilities to astronomical studies, a Laboratoire d’ Axtrophysique de Bordeaux researcher describes a novel, quite chaotic picture of how orbital worlds and solar systems form and evolve. Our familiar, orderly array, which was long taken as a norm, now seems a rare benign state as we learn about a usual crush of super-Earths, gas giants and rocky worlds in wildly shifting transits. See also by Formation of Terrestrial Planets by Raymond and Andre Izidoro at arXiv:1803.08830 and The Excitation of a Primordial Cold Asteroid Belt as an Outcome of the Planetary Instability by their group (1808.00609). The issue contains many entries from computations and astrochemistry to gravity waves and exoplanets.
The discovery of thousands of planets orbiting other stars has given us three surprising insights about our Solar System. First, we are weird: Our Solar System is a 1-in-2,000 rarity. Second, planet formation is a dynamic process, characterized by large-scale orbital drift as well as violent collisions and the ejection of young planets into interstellar space. Lastly, the second point may explain the first one—that is, how our Solar System formed is likely the root cause of our weirdness. (280)
Raymond, Sean, et al. Solar System Formation in the Context of Extra-Solar Planets. arXiv:1812.01033. Senior astrophysicists SR, University of Bordeaux, Andre Izidoro, Sao Paulo State University and Alessandro Morbidelli, University of Nice (search each) post a strongest analysis to date that our home Earth-Sun spatial and temporal array seems to be a rarest long term orderly, benign, conducive milieu for life to evolve and develop to a personsphere intelligence able to reach this auspicious conclusion. At the cusp of 2020, here is an incredible finding in our midst with implications for the fate and future not only of a geonate EarthKinder, but on to a self-chosen Ecosmos.
Exoplanet surveys have confirmed one of humanity's worst fears: we are weird. If our Solar System were observed with present-day Earth technology -- to put our system and exoplanets on the same footing -- Jupiter is the only planet that would be detectable. The statistics of exo-Jupiters indicate that the Solar System is unusual at the ~1% level among Sun-like stars (or ~0.1% among all stars). But why are we different? We argue that most Earth-sized habitable zone exoplanets are likely to form much faster than Earth, with most of their growth complete within the disk lifetime. Their water contents should span a wide range, from dry rock-iron planets to water-rich worlds with tens of percent water. Jupiter-like planets on exterior orbits may play a central role in the formation of planets with small but non-zero, Earth-like water contents.
Rees, Martin. Is There Life Beyond Earth? New Scientist. July 12, 2003. More considerations by the Cambridge University astronomer about the future options and august purpose for an integral earthkind in the universe.
More time lies ahead than has elapsed in the entire course of biological evolution. In those aeons, Earth could be the “seed” from which post-human life spreads through the galaxy. The fate of humanity could then have an importance that is truly cosmic: what happens here might conceivably make the difference between a near eternity filled with ever more complex and subtle forms of life and one filled with nothing but base matter. (27)
Rees, Martin. Living in a Multiverse. Ellis, George F. R., ed. The Far-Future Universe: Eschatology from a Cosmic Perspective. Philadelphia: Templeton Foundation Press, 2002. In his many universe scenario, only those finely tuned for life can contain intelligent planetary beings who are able to learn, contemplate and creatively carry forth this genesis. (Noted again in The Greening of the Galaxy)
Our Earth may have cosmic importance, as the one place form which life could spread through the universe. This realization raises the stakes from the earth to the entire cosmos. This new century, on this planet may be a defining moment for the cosmos. In the entire domain that cosmologists explore – ten billion years of time, ten billion light-years of space – the most crucial space-time location of all could be here and now. (84)
Sagan, Dorion. Biospheres. New York: McGraw-Hill, 1990. Prescient speculations from a Vladimir Vernadsky and Gaian perspective on how earth seems primed for a biological metamorphosis which spawns self-contained, autopoietic colonies. A key tenet is a fractal creation which recovers the ancient microcosm/macrocosm correspondence in a evolutionary universe.
Looking forward, it is possible to imagine a scenario in which the cosmos becomes animated in a way our intellectual forerunners and midnight star-gazers may never have imagined: if life continues to unfold “fractally” in the direction set down here - with individuality reestablishing itself at ever greater levels - biospheres will till the virgin soil of space itself… (184)
Sandberg, Anders, et al. Dissolving the Fermi Paradox. arXiv:1806.02404. Oxford University, Future of Humanity Institute scientist forecasters AS, Eric Drexler and Toby Ord contend that long after Frank Drake’s famous 1961 method to calculate anticipated cosmic civilizations, many new findings from genes to galaxies beg a whole scale revision. As the quotes say, and current works reach from other angles, even though the universe is filled with planetary objects, the answer to why no evidence has been found may well be that we Earthlings are the only sapiensphere species to have evolved this far.
The Fermi paradox is the conflict between a high probability of intelligent life elsewhere in the universe and the apparently absence we in fact observe. The expectation that the universe should be teeming with intelligent life is based on views that even if the probability of intelligent life developing at a given site is small, the sheer multitude of possible sites should yield many observable civilizations. We show that this conflict arises from the use of Drake-like equations, which implicitly assume certainty from highly uncertain parameters. We examine these parameters, incorporating models of chemical and genetic transitions on paths to the origin of life, and identify uncertainties that span multiple orders of magnitude. When the model is recast to represent realistic distributions of uncertainty, we find a substantial probability of there being no other intelligent life in our observable universe, and thus little surprise when we fail to detect any signs of it. (Abstract edits and excerpts)
Santos, Nuno, et al. Constraining Planet Structure and Composition from Stellar Chemistry. arXiv:1711.00777. An 11 member team from European observatories contribute to a growing sense that whole solar systems act altogether in a concerted way. The elemental makeup of the resident star is found to effect and determine what kind of orbital planets might be present. By this measure, different stellar populations can be evaluated for their relative propensity toward or away from a conducive habitability. See also Characterization of Exoplanet-Host Stars by this group at 1711.01112.
The chemical composition of stars that have orbiting planets provides important clues about the frequency, architecture, and composition of exoplanet systems. We compiled abundances for Fe, O, C, Mg, and Si in a large sample of solar neighbourhood stars that belong to different galactic populations. Assuming that overall the chemical composition of the planet building blocks will be reflected in the composition of the formed planets, we show that according to our model, discs around stars from different galactic populations, as well as around stars from different regions in the Galaxy, are expected to form rocky planets with significantly different iron-to-silicate mass fractions. Furthermore, the results may have impact on our understanding of the frequency of planets in the Galaxy, as well as on the existence of conditions for habitability. (Abstract)
Sardar, Ziauddin, ed. Rescuing All Our Futures. Westport, CT: Praeger, 1999. A theme of this website is the need for a global representation of all peoples in a peaceful, sustainable, much kinder abode. Within the palpable dominance of West and North over East and South, which augurs for a more of the same technological, consumptive future, these papers explore non-Western, indigenous, feminine options. Noted contributors include Susantha Goonatilake, Eleonara Masini, Sohail Inayatullah, Ivana Milojevic, Vinay Lal and Ashis Nandy. The traditional vision of the Maori peoples of New Zealand would make a suitable organic vision.
For the Maori, writes activist Ramana Williams, the appropriate term is the creation of a whanau. It means a vast universal family that connects the stars and the moon, the earth, and the sky and all life forms that reside therein, the world of animation and inanimation, the worlds of the living and the dead. (56)
Scharf, Caleb and Leroy Cronin. Quantifying the Origins of Life on a Planetary Scale. arXiv:1511.02549. The Columbia University astrobiologist and University of Glasgow biochemist scope out an advanced 2010s theoretical update of the 1960s Drake equation for better estimates of the likelihood of habitable abodes for organisms and peoples. See also A Probabilistic Framework for Quantifying Biological Complexity by Cronin, Stuart Marshall, and Alastair Murray at arXiv:1705.03460.
In this paper, we describe an equation to estimate the frequency of planetary “origin of life”-type events that is similar in intent to the Drake Equation but with some key advantages—specifically, our formulation makes an explicit connection between “global” rates for life arising and granular information about a planet. Our approach indicates scenarios where a shared chemical search space with more complex building blocks could be the critical difference between cosmic environments where life is potentially more or less abundant but, more importantly, points to constraints on the search. The possibility of chemical search-space amplification could be a major variance factor in planetary abiogenesis probabilities. (Significance)