III. Ecosmos: A Revolutionary Fertile, Habitable, Solar-Bioplanet Incubator Lifescape
H. Prolific ExoWorlds, Galactic Dynamics, Solar Orrerys, Habitable Zones, Biosignatures
Adibekyan, Vardan, et al. Which Type of Planets do We Expect to Observe in the Habitable Zone? Origins of Life and Evolution of Biospheres. Online June, 2016. With Pedro Figueira and Nuno Santos, University of Porto, Portugal, astrophysicists proceed to quantify our myriad new neighbors so as to identify and characterize what manner are likely to be in conducive locales as our home Earth. See also by the lead author Formation and Evolution of Exoplanets in Different Environments at arXiv:1701.01661. And how fantastic is it that a collaborative planetary species can begin a cosmic census across a widest stochastic diversity of potentially ovular worlds.
We used a sample of super-Earth-like planets detected by the Doppler spectroscopy and transit techniques to explore the dependence of orbital parameters of the planets on the metallicity of their host stars. We confirm the previous results (although still based on small samples of planets) that super-Earths orbiting around metal-rich stars are not observed to be as distant from their host stars as we observe their metal-poor counterparts to be. The orbits of these super-Earths with metal-rich hosts usually do not reach into the Habitable Zone (HZ), keeping them very hot and inhabitable. We found that most of the known planets in the HZ are orbiting their GK-type hosts which are metal-poor. The metal-poor nature of planets in the HZ suggests a high Mg abundance relative to Si and high Si abundance relative to Fe. These results lead us to speculate that HZ planets might be more frequent in the ancient Galaxy and had compositions different from that of our Earth. (Abstract)
Airapetian, Vladimir, et al. Impact of Space Weather on Climate and Habitability of Terrestrial-type Exoplanets. International Journal of Astrobiology. Online August, 2019. A forty-five member collaboration from NASA, across the USA, Austria, Germany, Japan, and Ireland provide an extended review and preview of this “astro-spheric” phase of a biocosmic spacescape which fills itself with evolutionary life bearing planets in solar incubators. A 206 page edition is accessible at arXiv:1905.05093.
Andrews, Sean, et al. The Disk Substructures at High Angular Resolution Project (DSHARP): 1. Motivation, Sample, Calibration, and Overview. Astrophysical Journal Letters. 869/2, 2018. An introduction to Focus on DSHARP Results, a 10 paper collection herein about the project and its first round of findings. Their significance is noted in Science as Hints of Young Planets Puzzle Theorists by Daniel Clery (362/1337, 2018), see second quote.
We introduce the Disk Substructures at High Angular Resolution Project (DSHARP), one of the initial Large Programs conducted with the Atacama Large Millimeter/submillimeter Array (ALMA). The primary goal is to find and characterize substructures in the spatial distributions of solid particles for a sample of 20 nearby protoplanetary disks, using very high resolution observations of their 240 GHz continuum emission. These data provide a first look at the small-scale disks that are relevant to planet formation, their prevalence, morphologies, spatial scales, spacings, symmetry, and amplitudes, with a variety of disk and stellar hosts. Here we discuss the motivation for the project, describe the survey design and the sample properties, detail the observations and data calibration, highlight some basic results, and provide a general overview of the key conclusions that are presented in more detail in a series of accompanying articles. (Abstract excerpt)
Arbesman, Samuel and Gregory Laughlin. A Scientometric Prediction of the Discovery of the First Potentially Habitable Planet with a Mass Similar to Earth. PLoS One. 5/10, 2010. Since detection of an earth-like extrasolar planet appears imminent, Harvard University and University of California, Santa Cruz, scientists propose a “novel metric of habitability” to facilitate its actual perception and veracity. By such lights, the epochal event is expected to occur in mid 2011.
Armstrong, David, et al. Transit Shapes and Self-Organizing Maps as a Tool for Ranking Planetary Candidates. arXiv:1611.01968. Astrophysicists Armstrong and Don Pallacco, University of Warwick, and Alex Santerne, University of Marseille, apply these neural methods to help analyze the vast amounts of data as the Kepler satellite finds ever more astral objects.
Aschwanden, Markus and Felix Scholkmann. Exoplanet Predictions Based on Harmonic Orbit. arXiv:1705.07138. In a 21st century scientific paper that would please Johannes Kepler some four hundred years on, astrophysicists can now discern and quantify that orbital planets do in fact display an intrinsic orderly motion. See also Self-Organizing Systems in Planetary Systems by Aschwanden at 1705.07138 and Order out of Randomness by MA, et al at 1708.03394.
The current exoplanet database includes 5454 confirmed planets and candidate planets observed with the KEPLER mission. We find 932 planet pairs from which we extract distance and orbital period ratios. While earlier studies used the Titius-Bode law or a generalized version with logarithmic spacing, which both lack a physical model, we employ here the theory of harmonic orbit resonances, which contains quantized ratios instead, to explain the observed planet distance ratios and to predict undetected exoplanets. Our orbital predictions includes 171 exoplanets, 2 Jupiter moons, one Saturn moon, 3 Uranus moons, and 4 Neptune moons. (Abstract excerpt)
Azua-Bustos, Armando and Cristian Vega-Martinez. The Potential for Detecting ‘Life as We Don’t Know It’ by Fractal Complexity Analysis. International Journal of Astrobiology. Online June, 2013. Pontificia Universidad Católica de Chile, and Instituto de Astrofísica de La Plata, Argentina scientists suggest a clever approach whereof the deep proclivity of living systems to form self-similar, iterative geometries could provide a viable indicator for searches of their presence across the cosmos.
Finding life in the Universe entirely different to the one evolved on Earth is probable. This is a significant constraint for life-detecting instruments that were sent and may be sent elsewhere in the solar system, as how could we detect life as ‘we don't know it’? How could we detect something when we have no prior knowledge of its composition or how it looks like? Here we argue that disregarding the type of lifeform that could be envisioned, all must share in common the attribute of being entities that decrease their internal entropy at the expense of free energy obtained from its surroundings. As entropy quantifies the degree of disorder in a system, any envisioned lifeform must have a higher degree of order than its supporting environment. Here, we show that by using fractal mathematics analysis alone, one can readily quantify the degree of entropy difference (and thus, their structural complexity) of living processes (lichen growths and plant growing patterns in this case) as distinct entities separate from its similar abiotic surroundings. This approach may allow possible detection of unknown forms of life based on nothing more than entropy differentials of complementary datasets. (Abstract)
Balbi, Amedeo and Manasvi Lingam. Beyond Mediocrity: How Common is Life?.. arXiv:2305.05395. University of Rome and Florida Institute of Technology exoscientists (search each) gather wide and deep considerations about to better evaluate the celestial presence of living systems. Yes, there may be many habitable worlds, but our thought process need go beyond this to engage a stochastic array of conditions, stellar varieties, and more contingencies. See also A Bayesian Analysis of Technological Intelligence in Land and Oceans by Manasvi Lingam, et al at arXiv:2305.05989.
The probability that life spontaneously emerges in a suitable environment (abiogenesis) is a major issue in astrobiology, which begs an accepted theory for the origin of life. In this paper, we adopt a Bayesian statistical approach to rigorously infer the lower evident-based bounds for abiogenesis. We note that the possible existence of many habitable worlds does not imply that life should be common in the universe. If habitable worlds are uncommon, for an agnostic prior, a deterministic scenario for the origin of life might be favoured over one where abiogenesis is a fluke event. (Excerpt)
Baraffe, I., et al. The Physical Properties of Extra-Solar Planets. Reports on Progress in Physics. 73/016901, 2010. An historic revision and expansion is going on about what kind of celestial cosmos that human beings find ourselves in, which has not yet run its course nor is widely appreciated. Rather than earthly biospheres as anomalous rarities, a default just a decade ago, planetary objects of any and all kind seem to abound wherever they can. This advance and vista has lately matured to the extent that astronomers can write this tutorial paper about their observation, formation, interior structure, atmospheres, evolution, star-planet interaction, and so on.
Basri, Gibor and Michael Brown. Planetesimals to Brown Dwarfs: What is a Planet? Annual Review of Earth and Planetary Sciences. 34/193, 2006. Earth, via its sentient species, through progress in instrumentation and observation, grows in knowledge about the formation and prevalence of orbital planetary objects.
Batygin, Konstantin, et al. Born of Chaos. Scientific American. May, 2016. Astrophysicists Batygin, Gregory Laughlin and Alessandro Morbidelli (search) write a popular article about the dynamic formation of the solar system and of our planet Earth just now being reconstructed, which all leads to an auspicious realization. In this post-Kepler satellite and worldwide collaborative era, it has been found that prolific arrays of orbital objects typically exhibit a contingent jumble of small rocky to giant gaseous planets in every which disordered location, especially close in to the host star. But our home solar community has a rare, well-spaced procession from one small Mercury to Venus, Earth and Mars onto larger outer worlds. Over its history, the planet Jupiter first moved toward the sun which cleaned out planetesimals and super-Earths, except for Mercury. It then tacked outward which led to further destructions or expulsions. See also Jupiter’s Decisive Role in the Inner Solar System’s Early Evolution by Batygin and Laughlin in the Proceedings of the National Academy of Sciences (112/4214, 2015) and the third quote.
In Brief: A wealth of new evidence from computer simulations as well as observations of planets throughout the galaxy is revealing new details of our solar system’s dynamic and violent history. The solar system’s configuration of small inner rocky worlds and large outer giants is anomalous in comparison with most other planetary systems, which have different architectures. (30)
Batygin, Konstantin, et al. The Origin of Universality in the Inner Edges of Planetary Systems. arXiv:2306.08822. KB, CalTech, Fred C. Adams and Juliette Becker, University of Michigan astrophysicists (search) describe some latest recognitions of independent celestial regularities as exhibited by any manner of solar orrery. See A Framework for the Architecture of Exoplanetary Systems at 2301.02374 and Order from Chaos by Lee Billings in Scientific American (May 2023) for concurrent notices. But will our special Earthumanity be able (in time) to realize the full implications without a phenomenal revolution?
he orbital period of the inner-most objects within the galactic census of planetary and satellite systems appears to be nearly universal. This paper presents a theoretical framework toward a simple explanation by way pfof the interplay between disk accretion, magnetic field generation by convective dynamos, and Kelvin-Helmholtz contraction. By this method we can express the magnetospheric truncation radius in astrophysical disks, to find that the relevant orbital frequency is independent of the mass of the host body. (Excerpt)