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

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

Lammer, Helmut, et al. What Makes a Planet Habitable? Astronomy and Astrophysics Review. 17/2, 2009. Some 15 senior members of the European astrospace community from Austria, Germany, France, Holland, Sweden, England, and onto Russia and the US, provide an extensive review of a galaxy and cosmos seemingly rift with worlds of every kind, as the Abstract notes. As these many studies express, an innately conducive milieu of solar systems, suitable biospheres, earth-analogs, seems increasingly evident. The paper agrees that life’s origin requires the common minimum of a membrane vesicle, metabolic proteins, and an information carrier, along with a driving energy gradient.

This work reviews factors which are important for the evolution of habitable Earth-like planets such as the effects of the host star dependent radiation and particle fluxes on the evolution of atmospheres and initial water inventories. We discuss the geodynamical and geophysical environments which are necessary for planets where plate tectonics remain active over geological time scales and for planets which evolve to one-plate planets. A classification of four habitat types is proposed. Class I habitats represent bodies on which stellar and geophysical conditions allow Earth-analog planets to evolve so that complex multi-cellular life forms may originate. Class II habitats includes bodies on which life may evolve but due to stellar and geophysical conditions that are different from the class I habitats, the planets rather evolve toward Venus- or Mars-type worlds where complex life-forms may not develop. Class III habitats are planetary bodies where subsurface water oceans exist which interact directly with a silicate-rich core, while class IV habitats have liquid water layers between two ice layers, or liquids above ice. Furthermore, we discuss from the present viewpoint how life may have originated on early Earth, the possibilities that life may evolve on such Earth-like bodies and how future space missions may discover manifestations of extraterrestrial life. (Abstract)

Laughlin, Gregory and Jack Lissauer. Exoplanetary Geophysics: An Emerging Discipline. Schubert, Gerald, ed.. Treatise on Geophysics. Amsterdam: Elsevier, 2015. A chapter for this 11 volume, 2nd edition by UC Santa Cruz, and NASA Ames scientists as terrestrial studies can now be extended to a galactic and cosmic scale. Who are we Earthlings to be the universe's way of describing and comprehending itself?

Lemonick, Michael. Can We Find Another Earth? Discover. March, 2002. The rapid progress in detecting stars with orbiting planets by perturbations in their movement due to the orbiting bodies, now over 100, leads to plans for telescopes able to focus in from Jupiter to Earth size globes.

Lemonick, Michael. Mirror Earth: the Search for Our Planet’s Twin. New York: Walker, 2012. Once science editor at Time magazine, the prolific author engagingly presents the incredible project and promise of finding another earth-like habitable world, which are now expected to abound across galaxy and cosmos. This is accomplished through vignette interviews with proponents such as William Borucki, Geoff Marcy, Dimitar Sasselov, David Charbonneau, and especially “female exoplaneteers” Natalie Batalha, Deborah Fisher, and Sara Seager. The abiding scenario and incentive is a fertile universe whereof bioworlds and evolutionary life flourishes. As an aside, I found this on the new book shelf at the Integrated Science and Engineering Library, University of Massachusetts at Amherst next to Destiny or Chance Revisited: Planets and their Place in the Cosmos by Stuart Taylor (Cambridge UP, 2012) which opts for the negative “rare Earth” view, now mostly discredited, of a forbidding spacescape where inhabited worlds are extreme accidents (which as usual says more about the writers).

Lineweaver, Charles and Aditya Chopra. The Habitability of Our Earth and Other Earths: Astrophysical, Geochemical, Geophysical, and Biological Limits on Planet Habitability. Annual Review of Earth and Planetary Sciences. Volume 40, 2012. An Australian National University astrophysicist and a geologist offer an extensive chapter that summarizes these epochal advances of the past decade. The result is the discovery of an expansive array of habitable zones from earth’s crust to galactic neighborhoods. By any measure, our collaborative humankind is presently coming upon a profoundly life, sentience, and people bearing genesis universe.

For life forms like us, the most important feature of the Earth is its habitability. Understanding habitability and using that knowledge to locate the nearest habitable planet may be crucial for our survival as a species. Over the past decade, expectations that the universe could be filled with habitable planets have been bolstered by the increasingly large overlap between terrestrial environments known to harbor life and the variety of environments on newly detected rocky exoplanets. The inhabited and uninhabited regions on Earth tell us that temperature and the presence of water are the main constraints can be used in a habitability classification scheme for rocky planets. Our compilation and review of recent exoplanet detections suggests that the fraction of stars with planets is 100%, and that the fraction with rocky planets may be comparably large. We review extensions to the circumstellar habitable zone including an energy habitable zone to start and maintain life, and the galactic habitable zone. (Abstract)

The increasingly large overlap between terrestrial environments known to harbor life and the surface environments of newly detected rocky exoplanets bolsters expectations that the universe may be filled with habitable planets. The fraction of stars with planets is approximately 100%. The fraction of stars with a rocky planet in the HZ could be comparably large. The water content of rocky planets is highly variable. This variability can be used to classify their habitability, e.g., ocean planets, Earth-like planets, and desert planets. (Summary Points)

Lissauer, Jack. Extrasolar Planets. Nature. 419/355, 2002. A news report about a galaxy and cosmos becoming filled with detectable planetary objects.

Natural philosophers have speculated on the existence of world around other suns for millennia. Now that real data are available, we find a diversity far beyond that expected by scientists, or science-fiction writers. (355)

Lissauer, Jack and Imke de Pater. Fundamental Planetary Science: Physics, Chemistry and Habitability. Cambridge: Cambridge University Press, 2014. It is a good sign that a novel scientific endeavor and subject area has come of age when a comprehensive text can be written about it. Lissauer, NASA Kepler project senior scientist, and de Pater, UC Berkeley and Delft University, situate a wealth of worlds in a conducive cosmos from Astrophysics and Atmospheres to Solar and ExoPlanetary Formation, Dynamics, Surfaces, Interiors, Moons, Comets, Meteors, Rings, and the Life that originated and arose to altogether be able to do this. But an implied Copernican revolution to an innately planet making universe, as so many ovular earths, has not yet occurred.

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.

Previous   1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9 | 10  Next  [More Pages]