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

H. Stellar Planetary Systems: A Stochastic Profusion of Galaxies, Solar Orrerys, and Habitable Zones

Lisse, Carey, et al. Abundant Circumstellar Silica Dust and SiO Gas Created by a Giant Hypervelocity Collision in the ~12 Myr HD172555 System. Astrophysical Journal. 701/2019, 2009. A team of astronomers using NASA’s Spitzer Space Telescope has found this evidence of a collision between a larger, Mercury size, and a smaller, Moon like object, which is then seen to imply how our earth formed by a similar impact. We cite as one example in this weekly, telephone-book size, periodical by thousands of researchers of humankind’s sentient surveillance and reconstruction of its galactic and cosmic environs, as if a planetary person.

Lucarini, Valerio, et al. Habitability and Multistability in Earth-like Planets. Astronomische Nachrichten. 334/6, 2013. With the Kepler satellite now having found a galaxy filled with orbital worlds, University of Hamburg, Germany, physicists are able, with colleagues worldwide and facilitated by 21st century instrumentation and computation, to begin to characterize their (bio)chemical atmospheres and weather dynamics. See also Bistability of the Climate around the Habitable Zone: A Thermodynamic Investigation by Lucarini, et al, in Icarus (226/1724, 2013). And significantly, as recorded in Global Climate as a Complex Dynamic System, this same team is also applying these skills and perceptions to better study and understand our own Earth weather.

We explore the potential multistability of the climate for a planet around the habitable zone. We focus on conditions reminiscent to those of the Earth system, but our investigation aims at presenting a general methodology for dealing with exoplanets. We provide a thorough analysis of the non-equilibrium thermodynamical properties of the climate system and explore, using a flexible climate model, how such properties depend on the energy input of the parent star, on the infrared atmospheric opacity, and on the rotation rate. It is possible to reproduce the multi-stability properties reminiscent of the paleoclimatologically relevant snowball (SB) - warm (W) conditions. These results have relevance for the general theory of planetary circulation and for the definition of necessary and sufficient conditions for habitability. (Abstract excerpt)

Astronomische Nachrichten (Astronomical Notes) is the oldest astronomy journal in publication, first appearing in 1823. It is based at the Leibniz Institute for Astrophysics in Potsdam, and online with Wiley where every issue, with some interruptions, can be accessed. In its worldwide venue it is said to cover “all fields of astrophysical research including instrumentation, numerical methods, solar and stellar astrophysics, extra galactic and cosmological research.”

MacPherson, Glenn and Alan Boss. Cosmochemical Evidence for Astrophysical Processes During the Formation of our Solar System. Proceedings of the National Academy of Sciences. 108/19152, 2011. Smithsonian Institution, and Carnegie Institution of Washington, planetary scientists contribute even more evidence that person and planet are quite at home in such a prolific genesis universe.

Through the laboratory study of ancient solar system materials such as meteorites and comet dust, we can recognize evidence for the same star-formation processes in our own solar system as those that we can observe now through telescopes in nearby star-forming regions. High temperature grains formed in the innermost region of the solar system ended up much farther out in the solar system, not only the asteroid belt but even in the comet accretion region, suggesting a huge and efficient process of mass transport. (Abstract, 19152) Planetary systems, including our own solar system, arise as a natural byproduct of star formation out of interstellar molecular clouds. (19152)

Madhusudan, Nikku, ed. ExoFrontiers: Big Questions in Exoplanetary Science. Online:IOP Science Books, 2022. A status wow collection as the profusion of global objects ever grows in amazing occurrence, diversity, fertility, surface and internal conditions, and many other aspects. Typical chapters are The Demographics of Exoplanets by Scott Gaudi, et al, Transit Spectroscopy by David Deming, et al, Orbital Dynamics and Architectures of Exoplanets by Daniel Fabrycky, and Exoplanetary Astrobiology by Victoria Meadows. But as this introduction alludes (e.g., Guadi) our home orderly orrery appears to be uniquely fortuitous for a sapient speciesphere to proceed with such spatial and temporal studies.

For example, the well-defined planetary mass/size categories of solar system planets may imply a certain quantization in size as a natural outcome of planetary formation. Similarly, their orbital locations may imply that giant planets should be preferentially formed at larger orbital separations, among other such trends. However, even in just the macroscopic parameters, the demographics of the thousands of exoplanets known indicate that the solar
system may arguably be the exception rather than the norm. (NM, 1-2)

Exoplanet surveys have revealed a wide diversity of orbital architectures, including information on orbital eccentricities, resonant period ratios, obliquities, and multi-planet systems. In parallel, theoretical studies have sought to link these discoveries to the formation and evolution of planetary systems. This chapter discusses the state of the art in our understanding of orbital dynamics and architectures of exoplanets, the important questions, opportunities and challenges. (Fabrycky)

Marcy, Geoffrey. The New Search for Distant Planets. Astronomy. October, 2006. The lead article in a special issue on extrasolar planets. To date over 200 such exoplanets have been found by various radial-velocity, transit, microlensing and direct-imaging methods. Over the past decade this burst of activity has also advanced our understanding of how planets form, their wide variety including free roaming giants, and an increasing detection of earth-like worlds and sun-like stars. A better sense of a solar “habitable zone” then accrues, along with how special is our home globe as it’s intelligent species begins to explore for and seek neighbors. The issue includes a fold out Atlas of Extrasolar Planets by space artist Lynette Cook.

Martin, Rebecca and Mario Livio. The Solar System as an Exoplanetary System. arXiv:1508.00931. With a wealth of satellite, observatory, and laboratory findings about a dynamic cosmos filled with stochastic orbital worlds to now draw upon, University of Nevada and Space Telescope Science Institute astronomers can assess the relative nature of our home environs. While not “extremely rare,” this sun and nine planet array is special for circular orbits, only one close-in planet, and an absence of disruptive “super-Earths.” See also papers by Giovanna Tinetti, Elke Pilat-Lohinger, and Allessandro Morbidelli for similar notice of a favorable, unique solar system, along with Tsvi Piran for even a favorable Milky Way galaxy.

In general, there are three aspects in which the Solar System differs most from other observed multi-planet systems. First, the low mean eccentricity of the planets in the Solar
System maybe somewhat special, although this may be accounted for by selection effects. Secondly, there is in the total lack of planets inside Mercury’s orbit. Massive planets migrating through the habitable zone can change the course of planet formation in that region. Overall, however, processes that could act to clear the inner part of the Solar Systems (such as giant planet migration), are believed to be operating within a non-negligible fraction of the exoplanet systems. Third, the lack of super-Earths in our Solar System is somewhat special and could have allowed the Earth to become habitable. (6-7)

Mason, John, ed. Exoplanets: Detection, Formation, Properties, Habitability. Berlin: Springer/Praxis Publishing, 2008. I recall my youth some 6 decades ago when any hope of finding other extrasolar planets was held to be quite remote. In the past few years a burst of discoveries fueled by advanced telescope and satellite instrumentation, along with computer enhancement, has found over 200 such objects from initial Jupiter giants to lately more Earth size neighbors.

Mayor, Michel and Pierre-Yves Frei. New Worlds in the Cosmos: The Discovery of the Exoplanets. Cambridge: Cambridge University Press, 2003. Progress in detecting large, Jupiter-type orbiting planets as of 2001.

Meadows, Victoria, et al. Community Report from the Biosignatures Standards of Evidence Workshop. arXiv:2210.14293. A major NASA, ASU plus document by over 80 astro-authorities such as Glada Arney, Laura Barge, Chris Kempes, Sanjoy Som and Sara Walker to scope out, get in front of, this vast enterprise of our Earthly search quest for other near and far animate presences. Many more contributors are cited to give this circa 2021 project a broad credibility. The comprehensive, graphic report goes on for 86 pages, with a long reference list

The search for life beyond the Earth is the premier goal of the NASA Astrobiology Program for the scientific missions that explore the environments of Solar System planets and exoplanets. However, the detection of extraterrestrial life is so challenging that many technical approaches will be needed to make a convincing claim. Current and upcoming research efforts aimed at past and extant life could avail a consensus framework to plan for, assess and discuss life detection. Given the importance of exolife searches to NASA, and its complex scientific challenges and conveyance, the astrobiology community needs to develop guidelines for biosignature findings, along with clear reporting protocols. (Executive Summary)

Menou, Kristen. Climate Stability of Habitable Earth-like Planets. Earth and Planetary Science Letters. 429/20, 2015. The University of Toronto astrophysicist adds to the latest research on exoworld chemical geologies and consequent atmospheres. A result is that the width of a solar habitable zone need be finessed by such variable properties so that inner and outer edges become less conducive, a central path is most preferred. See also Haqq-Misra and Turbet herein for more science.

The carbon–silicate cycle regulates the atmospheric CO2 content of terrestrial planets on geological timescales through a balance between the rates of CO2 volcanic outgassing and planetary intake from rock weathering. It is thought to act as an efficient climatic thermostat on Earth and, by extension, on other habitable planets. If, however, the weathering rate increases with the atmospheric CO2 content, as expected on planets lacking land vascular plants, the carbon–silicate cycle feedback can become severely limited. Here we show that Earth-like planets receiving less sunlight than current Earth may no longer possess a stable warm climate but instead repeatedly cycle between unstable glaciated and deglaciated climatic states. This has implications for the search for life on exoplanets in the habitable zone of nearby stars. (Abstract)

The key new feature of our analysis is the lack of stable climates on Earth-like planets lacking land vascular plants, at low enough insolation levels. This suggests that a subset of Earth-like planets located in the outer regions of habitable zones may be preferentially found in a frozen, rather than deglaciated, state. A globally frozen state might be observationally inferred from the very high albedo and the correspondingly low water content of the planet’s atmosphere. According to these results, some Earth-like planets in the outer habitable zone would also be caught in a transiently warm state with surface liquid water present only infrequently. (23)

Messeri, Lisa. Placing Outer Space: An Earthly Ethnography of Other Worlds. Durham, NC: Duke University Press, 2016. In response to 21st century discoveries of a prolific cosmos that appears to innately seed itself with planetary objects, a University of Virginia professor of science, technology, and society describes her project to broach a conceptual vision and response. By any measure, a vital imaginary shift is in order to appreciate our individual and collective identity as roundly global in kind, verily that habitable bioworlds seem to be nature’s essential feature. As the note says, she imbedded in the planet search community with interviews and travel, which welcomed her endeavor. A prior guide is Gayatri Spivak’s (search) sense of “planetarity,” by this novel vista, our allegiance is not to tribes or nations, but as Earthlings whose wholly home is this precious biosphere. See also her Op-Ed: What’s So Special About Another Earth? in the NY Times (August 25, 2016) on the finding of our Proxima Centauri neighbor.

In Placing Outer Space Lisa Messeri traces how the place-making practices of planetary scientists transform the void of space into a cosmos filled with worlds that can be known and explored. Making planets into places is central to the daily practices and professional identities of the astronomers, geologists, and computer scientists Messeri studies. She takes readers to the Mars Desert Research Station and a NASA research center to discuss ways scientists experience and map Mars. At a Chilean observatory and in MIT's labs she describes how they discover exoplanets and envision what it would be like to inhabit them. Today’s planetary science reveals the universe as densely inhabited by evocative worlds, which in turn tells us more about Earth, ourselves, and our place in the universe.

Mettler, Jean-Noel, et al.. Earth as an Exoplanet. III. Using Empirical Thermal Emission Spectra as Input for Atmospheric Retrieval of an Earth-Twin Exoplanet. arXiv:2310.02634. In three entries since October 2000, ETH Zurich astrophysicists propose an approach to quantify and evaluate our own candidate habitable bioworld as some manner of baseline guide. Prior versions are Earth as an Exoplanet. II. Earth's Time-variable Thermal Emission and Its Atmospheric Seasonality of Bioindicators (2210.05414) and Earth as an Exoplanet: I. Time variable thermal emission using spatially resolved MODIS data. (2010.02589).

In these studies, we treat Earth as an exoplanet and investigate our home planet by means of a potential future mid-infrared (MIR) space mission called the Large Interferometer For Exoplanets (LIFE). Key findings include: Our world is a temperate habitable planet with abundant CO2, H2O, O3, and CH4; seasonal variations in temperature, and albedo are detectable; and Earth's variable H2O profile and patchy clouds lead to biased results for atmospheric make up. Our results suggest that LIFE could correctly identify Earth as a planet where life could thrive, with detectable levels of bioindicators, a temperate climate, and surface conditions allowing liquid surface water. (Abstract)

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