The Galactic Habitable Zone
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The Galactic Habitable Zone
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Author :
language : en
Publisher:
Release Date : 2009
The Galactic Habitable Zone written by and has been published by this book supported file pdf, txt, epub, kindle and other format this book has been release on 2009 with categories.
We propose the concept of a "Galactic Habitable Zone" (GHZ). Similar to the circumstellar habitable zone (CHZ), the GHZ is that region in a spiral galaxy where life can exist. The width of the GHZ is controlled by two factors. The inner (closest to the center of the galaxy) limit is set by threats to complex life: nearby transient sources of ionizing radiation and comet impacts. Such threats tend to increase close to the galactic center. The outer limit is imposed by galactic chemical evolution, specifically the abundance of heavier elements. Observation of stars in the Milky Way galaxy suggests that the outer reaches of a spiral galaxy may be too poor in heavy elements to allow terrestrial complex life to exist.
Why Are We Here
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Author : Moiya McTier
language : en
Publisher:
Release Date : 2021
Why Are We Here written by Moiya McTier and has been published by this book supported file pdf, txt, epub, kindle and other format this book has been release on 2021 with categories.
In Chapter 3, we zoom out from planets to get a better understanding of the dynamical and chemical evolution of the Milky Way, which are both crucial for constraining the Galaxy's GHZ. We use the Extreme Deconvolution Gaussian Mixture Model to identify overdensities of stars in both velocity and action space, called moving groups and orbit groups, respectively. Velocities and actions are calculated using data from the early third data release of the Gaia mission. When we analyze the chemical abundance distributions of these moving and orbit groups with GALAH DR3 data, we find that using velocities alone to define moving groups, or even using velocities and actions together, yields an incomplete view of the underlying density distributions and their origins. Our chemical analysis also confirms expected chemical evolution trends in the Solar neighborhood. Next, we explore the effects of stellar motion and galactic dynamics on the habitability of planets in different regions of the Galaxy.
Probabilities In The Galaxy
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Author : Klaus Piontzik
language : en
Publisher: BoD – Books on Demand
Release Date : 2019-03-04
Probabilities In The Galaxy written by Klaus Piontzik and has been published by BoD – Books on Demand this book supported file pdf, txt, epub, kindle and other format this book has been release on 2019-03-04 with Science categories.
The method used in the following chapters of the book is referred to in mathematics as an axiomatic approach. From the analysis of empirical data of the Kepler satellite hypotheses are drawn, which are called approaches and axioms. The derived statements are formulated as sentences to which certain probabilities are assigned. All axioms and sentences lead to an overall presentation of the situation, which can then be used as a working hypothesis. Namely as a working hypothesis regarding the abundance of habitable, Earth-like planets, as well as life, intelligence and civilizations in our galaxy. It is unprobable that we are alone in the universe. It is more probable that we are not alone.
Worlds Beyond Our Own
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Author : Sujan Sengupta
language : en
Publisher: Springer
Release Date : 2014-10-28
Worlds Beyond Our Own written by Sujan Sengupta and has been published by Springer this book supported file pdf, txt, epub, kindle and other format this book has been release on 2014-10-28 with Science categories.
This is a book on planets: Solar system planets and dwarf planets. And planets outside our solar system – exoplanets. How did they form? What types of planets are there and what do they have in common? How do they differ? What do we know about their atmospheres – if they have one? What are the conditions for life and on which planets may they be met? And what’s the origin of life on Earth and how did it form? You will understand how rare the solar system, the Earth and hence life is. This is also a book on stars. The first and second generation of stars in the Universe. But in particular also on the link between planets and stars – brown dwarfs. Their atmospheric properties and similarities with giant exoplanets. All these fascinating questions will be answered in a non-technical manner. But those of you who want to know a bit more may look up the relevant mathematical relationships in appendices.
The Privileged Planet
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Author : Guillermo Gonzalez
language : en
Publisher: Regnery Gateway
Release Date : 2020-01-07
The Privileged Planet written by Guillermo Gonzalez and has been published by Regnery Gateway this book supported file pdf, txt, epub, kindle and other format this book has been release on 2020-01-07 with Science categories.
Earth. The Final Frontier Contrary to popular belief, Earth is not an insignificant blip on the universe’s radar. Our world proves anything but average in Guillermo Gonzalez and Jay W. Richards’ The Privileged Planet: How Our Place in the Cosmos Is Designed for Discovery. But what exactly does Earth bring to the table? How does it prove its worth among numerous planets and constellations in the vastness of the Milky Way? In The Privileged Planet, you’ll learn about the world’s life-sustaining capabilities, water and its miraculous makeup, protection by the planetary giants, and how our planet came into existence in the first place.
Habitability Of The Universe Before Earth
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Author :
language : en
Publisher: Academic Press
Release Date : 2017-12-11
Habitability Of The Universe Before Earth written by and has been published by Academic Press this book supported file pdf, txt, epub, kindle and other format this book has been release on 2017-12-11 with Science categories.
Habitability of the Universe before Earth: Astrobiology: Exploring Life on Earth and Beyond (series) examines the times and places—before life existed on Earth—that might have provided suitable environments for life to occur, addressing the question: Is life on Earth de novo, or derived from previous life? The universe changed considerably during the vast epoch between the Big Bang 13.8 billion years ago and the first evidence of life on Earth 4.3 billion years ago, providing significant time and space to contemplate where, when and under what circumstances life might have arisen. No other book covers this cosmic time period from the point of view of its potential for life. The series covers a broad range of topics encompassing laboratory and field research into the origins and evolution of life on Earth, life in extreme environments and the search for habitable environments in our solar system and beyond, including exoplanets, exomoons and astronomical biosignatures. Provides multiple hypotheses on the origin of life and distribution of living organisms in space Explores the diversity of physical environments that may support the origin and evolution of life Integrates contemporary views in biology and cosmology, and provides reasons that life is far more mobile in space than most people expect Includes access to a companion web site featuring supplementary information such as animated computer simulations
The Impossibility Of Extraterrestrial Life
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Author : Ben Tripp
language : en
Publisher: Impossibility of Extraterrestrial Life
Release Date : 2019-02-21
The Impossibility Of Extraterrestrial Life written by Ben Tripp and has been published by Impossibility of Extraterrestrial Life this book supported file pdf, txt, epub, kindle and other format this book has been release on 2019-02-21 with categories.
While the number of stars in the universe is very large - some 300,000,000,000 in the Milky Way Galaxy alone - there are only a relatively small number which could provide life-supporting heat for a habitable planet The primary restriction is the necessity of being in the Galactic Habitable Zone. This is followed by the secondary restriction of being in one of the few arms of the galaxy. These two restrictions reduce the number of possibilities to just a few million. Next the star must be 'hot'. Red Dwarfs will not do as they are 'relatively-speaking' cool, which necessitates that any planet be quite close in order to be in their 'habitable zone'. However 'close' means that the gravity of the star would distort the planet causing it to lock up with one side always facing the star. While numerous planets have been discovered near Red Dwarf stars those in the habitable zones are always very close to the star and are commonly understood to be orbiting the star in just a few days. If a person could stand on one of these planets the star would take up a large portion of the sky and because the planet would be 'locked up', the hot side would be much too hot and the other side would be much too cold. In fact it would be so cold that even CO2 would be frozen on the cold side along with whatever water had been present. Therefore even being in the twilight zone would not enable habitability. Furthermore the proximity of the star and the overpowering pull of its gravity would eliminate any possibility of there being a moon. However we understand from the way that the Earth operates that an axial tilt is necessary and of course the Moon is the factor that sets up and maintains the Axial Tilt. Without a properly-sized Moon there would not be any axial tilt meaning that even the Earth would be barely habitable and possibly not habitable at all. So Red Dwarfs are out which eliminates 95% of all of the stars in the universe including those within the Galactic habitable Zone. The next factor of interest relates to singularity. A star must be singular in order for any potentially-habitable planet to enjoy a circular orbit. The only way to eliminate this restriction is for the planet to be so close to its host star that the other stars in the group will not cause its orbit to deviate from circularity. However as we have already seen 'close' will not work.Getting setup for habitability is not a trivial affair with temperature control being paramount. In the case of the Earth, there are numerous factors involved with temperature control and being properly distanced from the host star is at the top of the list. Mars is not habitable and any idea that it can be colonized is bizarre. While the temperature range is similar to Antarctica - which is certainly not habitable - neither is there a magnetic field. Hence there is no protection from cosmic radiation. The Earth has a magnetic field but even in this case it is a transient and will not be able to provide protection for very much longer. However it will probably be longer than the Greenhouse Effect will be able to regulate the temperature on the Earth's surface to within the habitability range. This would seem to necessitate that any far-away planet must also have a Greenhouse Effect in place to regulate temperature but as we observe what is happening on Earth there is a limit to what the Greenhouse Effect can accomplice. The Earth is warming up and will continue to warm up. While a few degrees does seem trivial, our scientists recognize that warming up will have major consequences.The Earth is barely habitable and will not be habitable for very much longer. What can we possibly expect from a far-away planet? It all boils down to the conclusion that 'Extraterrestrial Life is Impossible'.
Rare Earth
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Author : Peter D. Ward
language : en
Publisher: Springer
Release Date : 2007-05-08
Rare Earth written by Peter D. Ward and has been published by Springer this book supported file pdf, txt, epub, kindle and other format this book has been release on 2007-05-08 with Science categories.
What determines whether complex life will arise on a planet, or even any life at all? Questions such as these are investigated in this groundbreaking book. In doing so, the authors synthesize information from astronomy, biology, and paleontology, and apply it to what we know about the rise of life on Earth and to what could possibly happen elsewhere in the universe. Everyone who has been thrilled by the recent discoveries of extrasolar planets and the indications of life on Mars and the Jovian moon Europa will be fascinated by Rare Earth, and its implications for those who look to the heavens for companionship.
How To Find A Habitable Planet
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Author : James F. Kasting
language : en
Publisher: Princeton University Press
Release Date : 2021-12-07
How To Find A Habitable Planet written by James F. Kasting and has been published by Princeton University Press this book supported file pdf, txt, epub, kindle and other format this book has been release on 2021-12-07 with Science categories.
The amazing science behind the search for Earth-like planets Ever since Carl Sagan first predicted that extraterrestrial civilizations must number in the millions, the search for life on other planets has gripped our imagination. Is Earth so rare that advanced life forms like us—or even the simplest biological organisms—are unique to the universe? How to Find a Habitable Planet describes how scientists are testing Sagan's prediction, and demonstrates why Earth may not be so rare after all. James Kasting has worked closely with NASA in its mission to detect habitable worlds outside our solar system, and in this book he introduces readers to the advanced methodologies being used in this extraordinary quest. He addresses the compelling questions that planetary scientists grapple with today: What exactly makes a planet habitable? What are the signatures of life astronomers should look for when they scan the heavens for habitable worlds? In providing answers, Kasting explains why Earth has remained habitable despite a substantial rise in solar luminosity over time, and why our neighbors, Venus and Mars, haven't. If other Earth-sized planets endowed with enough water and carbon are out there, he argues, chances are good that some of those planets sustain life. Kasting describes the efforts under way to find them, and predicts that future discoveries will profoundly alter our view of the universe and our place in it. This book is a must-read for anyone who has ever dreamed of finding other planets like ours—and perhaps even life like ours—in the cosmos. In a new afterword, Kasting presents some recent breakthroughs in the search for exoplanets and discusses the challenges facing space programs in the near future.
The Galactic Club
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Author : RONALD N. BRACEWELL
language : en
Publisher:
Release Date : 1974
The Galactic Club written by RONALD N. BRACEWELL and has been published by this book supported file pdf, txt, epub, kindle and other format this book has been release on 1974 with categories.
