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

H. Prolific ExoWorlds, Galactic Dynamics, Solar Orrerys, Habitable Zones, Biosignatures

Cabrol, Nathalie. Using Machine Learning to Optimize the Search for Biosignatures. Nature Astronomy. 7/3, 2023. We cite this article by the senior French-American astrobiologist and director of the Carl Sagan Center for the Study of Life in the Universe at the SETI Institute as such a far and wide celestial neighborhood census becomes facilitated by AI methods (see our EI section).

A probabilistic machine learning-based framework for recognizing and predicting microbial landscape patterns at nested spatial scales was developed. The approach substantially increased the probability of detecting biosignatures when tested at a Martian analogue in the high Andes. This search tool has applications for detecting biosignatures on terrestrial or icy planets.

Carroll, Michael. The Hunt for Earth’s Bigger Cousins. Astronomy. April, 2017. As worldwide humankind continues to explore, discover and quantify a widest array of planetary objects, many articles as this keep up with their findings. Here a science writer and author of Earths of Distant Suns (2016) notes that a most prevalent size seems to be 2 to 10 times our home planet, which are known as Super Earths or Sub Neptunes. We also enter because in several places it is observed that this orderly solar system is an anomaly amongst the usual chaos, continents in motion via plate tectonics are rare, wholly gaseous atmospheres are common, and so on. So the case of an extraordinary great Earth continues to build.

Cassan, Arnaud, et al. One or More Bound Planets per Milky Way Star from Microlensing Observations. Nature. 481/167, 2012. A team of some 41 scientists within the Probing Lensing Anomalies Network (PLANET) collaboration, based at Institut d’Astrophysique de Paris, Université Pierre and Marie Curie, further support the 21st century revolution to realize an innately conducive cosmos that seemingly seeds itself with as many worlds as there are stars in the sky.

We conclude that stars are orbited by planets as a rule, rather than the exception. (167) Planets around stars in our Galaxy thus seem to be the rule rather than the exception. (169)

Chang, Kenneth. 7 Earth-Size Planets Orbit Dwarf Star, NASA and European Astronomers Say. New York Times. February 23, 2017. As a graphic display to lead the front page, this is a report about the widely-noted discovery of the most solar system-like, multi-world array found to date. We also note that while a cooperative humanity can reveal such frontiers, as readers know, the rest of the daily news was about a precious planet consumed with barbaric, terminal violence.

Not just one, but seven Earth-size planets that could potentially harbor life have been identified orbiting a tiny star not too far away, offering the first realistic opportunity to search for signs of alien life outside the solar system. The planets orbit a dwarf star named Trappist-1, about 40 light-years, or 235 trillion miles, from Earth. All seven are very close to the dwarf star, circling more quickly than the planets in our solar system. The innermost completes an orbit in just 1.5 days. The farthest one completes an orbit in about 20 days. That makes the planetary system more like the moons of Jupiter than a larger planetary system like our solar system.

Chen, Jingjing and David Kipping. Probabilistic Inference of the Masses and Radii of Other Worlds. arXiv:1603.08614. Columbia University astronomers look back upon the past two decades, especially by the Kepler satellite, of novel planetary discoveries to propose four object classes – Terran (rocky earths), Neptunian worlds, larger Jovian orbs (both gaseous) and stars. By these views, the so-called Super Earths actually appear to be mini-Neptunes or gas dwarfs. It is thus concluded: This independent analysis adds further weight to the emerging consensus that rocky Super-Earths represent a narrower region of parameter space than originally thought. Effectively, then, the Earth is the Super-Earth we have been looking for.

Chiang, Eugene and Gregory Laughlin. The Minimum-Mass Extrasolar Nebula: In Situ Formation of Close-in Super-Earths. Monthly Notices of the Royal Astronomical Society. 431/3444, 2013. In a typical paper now infusing such august journals, University of California, Berkeley, and Santa Cruz, astrophysicists continue to show how profligate cosmic nature is when it comes to seeding herself with all manner of solar-planetary systems and ovular bioworlds.

Close-in super-Earths, with radii R ≈ 2–5R⊕ and orbital periods P < 100 d, orbit more than half, and perhaps nearly all, Sun-like stars in the Universe. We use this omnipresent population to construct the minimum-mass extrasolar nebula (MMEN), the circumstellar disc of solar-composition solids and gas from which such planets formed, if they formed near their current locations and did not migrate. In a series of back-of-the-envelope calculations, we demonstrate how in situ formation in the MMEN is fast, efficient, and can reproduce many of the observed properties of close-in super-Earths, including their gas-to-rock fractions. Testable predictions are discussed. (Abstract)

Cockell, Charles, et al.. Habitability. Astrobiology. 16/1, 2016. As an exceptional, sapient biosphere begins to survey and quantify a prolific galactic and cosmic neighborhood, an 18 member team from across Europe, including Helmet Lammer, posts this consideration about conducive spacescape zones for incubator solar systems. We quote the long Abstract, and wonder whom over the great Earth is doing this? See also for example The Inner Edge of the Habitable Zone for Synchronously Rotating Planets around Low-Mass Stars at arXiv:1602.05176.

Habitability is a widely used word in the geoscience, planetary science, and astrobiology literature, but what does it mean? In this review on habitability, we define it as the ability of an environment to support the activity of at least one known organism. We adopt a binary definition of “habitability” and a “habitable environment.” An environment either can or cannot sustain a given organism. However, environments such as entire planets might be capable of supporting more or less species diversity or biomass compared with that of Earth. A clarity in understanding habitability can be obtained by defining instantaneous habitability as the conditions at any given time in a given environment required to sustain the activity of at least one known organism, and continuous planetary habitability as the capacity of a planetary body to sustain habitable conditions on some areas of its surface or within its interior over geological timescales. We also distinguish between surface liquid water worlds (such as Earth) that can sustain liquid water on their surfaces and interior liquid water worlds, such as icy moons and terrestrial-type rocky planets with liquid water only in their interiors. This distinction is important since, while the former can potentially sustain habitable conditions for oxygenic photosynthesis that leads to the rise of atmospheric oxygen and potentially complex multicellularity and intelligence over geological timescales, the latter are unlikely to. Habitable environments do not need to contain life. Although the decoupling of habitability and the presence of life may be rare on Earth, it may be important for understanding the habitability of other planetary bodies (Abstract)

Cooke, Ilsa and Ian Sims. Experimental Studies of Gas-Phase Reactivity in Relation to Complex Organic Molecules in Star-Forming Regions. ACS Earth and Space Chemistry. Online June, 2019. We note this entry by University of Rennes, CNRS, France astrophysical chemists as an example in this new journal of how sophisticated these research endeavors have become as they quantify ever increasing evidence of an intrinsic biocosmic essence which brings forth, complexifies, develops and evolves as it reaches our human ability and purpose to retrospectively learn and continue For later work see Variability due to climate and chemistry in observations of oxygenated Earth-analogue exoplanets at arXiv:2209.07566.

The field of astrochemistry concerns the formation and abundance of molecules in the interstellar medium, star-forming regions, exoplanets, and solar system bodies. These astrophysical objects contain the chemical material from which new planets and solar systems are formed. Around 200 molecules have thus far been observed in the interstellar medium; almost half containing six or more atoms and considered “complex” by astronomical standards. All of these complex molecules consist of at least one carbon atom and thus the term complex organic molecules (COMs) has been coined by the astrochemical community. In the following review, we present recent laboratory efforts to produce quantitative kinetic data for gas-phase reactions at low temperatures. (Abstract excerpt)

The scope of ACS Earth and Space Chemistry includes the application of analytical, experimental and theoretical chemistry to investigate research questions relevant to the Earth and Space. The journal notes the highly interdisciplinary nature of research in this area, with chemistry and chemical research tools as the unifying theme. It publishes broadly in the domains of high- and low-temperature geochemistry, atmospheric chemistry, marine chemistry, planetary chemistry, astrochemistry, and analytical geochemistry.

Cuntz, Manfred, et al. Habitability of Super-Earth Planets around Main-sequence Stars including Red Giant Branch Evolution. International Journal of Astrobiology. 11/1, 2012. As this Kepler planet finder satellite era increasingly reveals a creative cosmos that seems to seed itself with a stochastic infinity of orbiting orbs, University of Texas, Potsdam Institute, and University of Guanajuato, Mexico astrophysicists quantify the suitability of such big brother worlds for life’s inevitable appearance and evolution. Please consider with Gowanlock, et al, as Great Earth comes to explore with amazement a grand new neighborhood.

In a previous study published in Astrobiology, we focused on the evolution of habitability of a 10 M⊕ super-Earth planet orbiting a star akin to the Sun. This study was based on a concept of planetary habitability in accordance with the integrated system approach that describes the photosynthetic biomass production taking into account a variety of climatological, biogeochemical and geodynamical processes. In the present study, we pursue a significant augmentation of our previous work by considering stars with zero-age main-sequence masses between 0.5 and 2.0 M⊙ with special emphasis on models of 0.8, 0.9, 1.2 and 1.5 M⊙. Our models of habitability consider geodynamical processes during the main-sequence stage of these stars as well as during their red giant branch evolution. Pertaining to the different types of stars, we identify the so-called photosynthesis-sustaining habitable zone (pHZ) determined by the limits of biological productivity on the planetary surface. We obtain various sets of solutions consistent with the principal possibility of life. (15)

Deeg, Hans and Juan Antonio Belmonte, eds. Handbook of Exoplanets. International: SpringerLink, 2018. If ever a vast frontier has opened and become accessible, it is the 21st century’s realization of a fecund universe that innately fills itself with all manner of planetary worlds and solar systems. Beyond 20th century space exploration, a galactic and cosmic neighborhood now beckons for all our futures. After a past decade of prolific global projects, novel instrumentations and computer analyses, this 3,500 volume with 160 authoritative entries is a major documentation to date. Atmospheric Biosignatures, Characterizing Exoplanet Habitability, Dynamic Evolution of Planetary Systems, Exoplanet Catalogs, Host Star Astroseismology, Formation of Giant Planets and Super-Earths, Habitability in Binary Star Systems, Mapping Exoplanets, Planet-Star Interactions, Earth’s Biosignatures Over Time, The Habitable Zone, are just a few areas. As appropriate for our common Earthwise geo-sapience, the entire text is posted online as PDFs on its SpringerLink site. Here are some Abstract edits.

Life on Earth is molecular in nature, with attributes such as information processing and catalysis as a result of those molecules and interactions among them. A general model for life must require (i) a source of energy to build and sustain biochemical complexity and information processing; (ii) elemental raw materials to construct molecules having specific properties and reactivity; (iii) a solvent that supports the range of interactive biomolecules; and (iv) physicochemical conditions in which life’s molecules can be synthesized, stablized, and combine. For life on Earth, these requirements are: (i) light energy in visible-to-near-infrared wavelengths or chemical energy by oxidation–reduction disequilibrium (ii) the biogenic elements carbon, hydrogen, oxygen, nitrogen, phosphorus, and sulfur (iii) liquid water, and (iv) specific ranges in temperature, pH, salinity, pressure, and environmental factors. (Tori Hoehler, et al, Life’s Requirements)

Recent discoveries of exoplanets by both ground-based and space-based surveys indicate that terrestrial-size planets are common around other stars. This raises an intriguing possibility of extraterrestrial life on these planets, which may be detectable with upcoming detailed characterization missions. Consequently, the concept of the habitable zone has been defined to focus the search for life on those planets most likely to be able to sustain liquid water on their surface for extended durations. This chapter addresses the need for such definition, the current state-of-the-art of models that are used to define the habitable zone, and concludes with applications to current and future missions. (Ravi Kopparapu, The Habitable Zone)

A habitable exoplanet is a world that can maintain stable liquid water on its surface. Techniques and approaches to characterizing such worlds are essential, as performing a census of Earthlike planets that may or may not have life will evince how frequently life originates and is sustained on worlds other than our own. Approaches to making the types of measurements that indicate habitability are diverse and have different considerations for the required wavelength range, spectral resolution, maximum noise levels, stellar host temperature, and observing geometry. (Tyler Robinson, Exoplanet Habitability)

The discovery of exoplanets has both focused and expanded the search for extraterrestrial intelligence. The consideration of Earth as an exoplanet, the knowledge of the orbital parameters of individual exoplanets, and the prevalence of exoplanets found throughout the galaxy have altered the search strategies of communication SETI efforts. Future efforts to characterize individual planets with imaging and via transit, will allow for searches for a variety of technosignatures on their surfaces, in their atmospheres, and in orbit around them. (Jason Wright, Exoplanets and SETI)

Deeg, Hans, et al, eds. Extrasolar Planets. Cambridge: Cambridge University Press, 2008. A report from the XVI Canary Islands Winter School of Astrophysics (doesn’t that sound pleasant) on how to detect them, their frequency, characterization, how they might have formed, favorable solar systems, biomarkers, and so on.

Del Genio, Anthony, et al. The Inner Solar System’s Habitability Through Time. arXiv:1807.04776. We cite this entry by Del Genio, NASA Goddard, David Brain, University of Colorado, Lena Noack, Free University of Berlin and Laura Schaefer, Arizona State University for its content, and to note how later 2010s worldwide collaborations are proceeding to reconstruct how our home world came to form and survive, and to scan the celestial raiment as it becomes filled with all manner of near and far neighbor vicarious solar systems and orbital worlds.

Earth, Mars, and Venus, irradiated by an evolving Sun, have had fascinating but diverging histories of habitability. Although only Earth's surface is considered to be habitable today, all three planets might have simultaneously been habitable early in their histories. We consider how physical processes that have operated similarly or differently on these planets determined the creation and evolution of their atmospheres and surfaces over time. These include the geophysical and geochemical processes that determined the style of their interior dynamics and the presence or absence of a magnetic field; the surface-atmosphere exchanges that acted as a source or sink; the Sun-planet interactions that controlled escape of gases to space; and the atmospheric processes that serve to determine climate and habitability. (Abstract)

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