FREE AN INTRODUCTION TO ASTROBIOLOGY PDF David A. Rothery,Iain Gilmour,Mark A. Sephton | 366 pages | 31 Oct 2011 | CAMBRIDGE UNIVERSITY PRESS | 9781107600935 | English | Cambridge, United Kingdom Astrobiology - Wikipedia Astrobiologyformerly known as exobiologyis an interdisciplinary scientific field concerned with the originsearly evolutiondistribution, and future of life in the universe. Astrobiology considers the question of whether extraterrestrial life exists, and if it does, how humans can detect it. Astrobiology makes use of molecular biologybiophysicsbiochemistrychemistryastronomyphysical cosmologyexoplanetology and geology to investigate the possibility of life on other worlds and help recognize biospheres that might be different from that on Earth. This interdisciplinary field encompasses research on the origin of planetary systemsorigins of organic compounds in spacerock-water-carbon interactions, abiogenesis on Earth, planetary habitabilityresearch on biosignatures for life detection, and studies on the potential for life to adapt to challenges on Earth and in outer space. Biochemistry may have begun shortly after the Big Bang Current studies on the planet Mars by the Curiosity and Opportunity rovers are searching for evidence of ancient life as well as plains related to An Introduction to Astrobiology rivers or lakes that may have been habitable. Even if extraterrestrial life is never discovered, the interdisciplinary nature of astrobiology, and the cosmic and evolutionary perspectives An Introduction to Astrobiology by it, may still result in a range of benefits here on Earth. The term was first proposed by the Russian Soviet astronomer Gavriil Tikhov in The synonyms of astrobiology are diverse; however, the synonyms were structured in relation to the most important sciences implied in its development: astronomy and biology. The term exobiology was coined by molecular biologist and Nobel Prize winner Joshua Lederberg. Another term used in the past is xenobiology"biology of the foreigners" a word used in by science fiction writer Robert Heinlein in An Introduction to Astrobiology work The Star Beast. Since alternate chemistry analogs to some life-processes have been created in the laboratory, xenobiology is now considered as an extant subject. While it is an emerging and developing field, the question of whether life exists elsewhere in the universe is An Introduction to Astrobiology verifiable hypothesis and thus a valid line of scientific inquiry. Planetary scientist David Grinspoon calls astrobiology a field of natural philosophy, grounding speculation on the unknown, in known scientific theory. Space Program. NASA's Viking missions to Mars, launched inincluded three biology experiments designed to look for metabolism of present life on Mars. Advancements in the fields of astrobiology, observational astronomy and discovery of large varieties of extremophiles with An Introduction to Astrobiology capability to thrive in the harshest environments An Introduction to Astrobiology Earth, have led to speculation that life may possibly be thriving on many of the extraterrestrial bodies in the universe. There is a growing body of evidence to suggest that Mars has previously had a considerable amount of water on its surface[37] [38] water being considered an essential precursor to the development of carbon-based life. Missions specifically designed to search for current life on Mars An Introduction to Astrobiology the Viking program and Beagle 2 probes. The Viking results An Introduction to Astrobiology inconclusive, [40] and Beagle 2 failed minutes after landing. In latethe Phoenix lander probed the environment for past and present planetary habitability of microbial life on Marsand An Introduction to Astrobiology the history of water there. The European Space Agency 's astrobiology roadmap fromidentified five main research topics, and specifies several key scientific objectives for each topic. The five research topics are: [42] 1 Origin and evolution of planetary systems; 2 Origins of organic compounds in space; 3 Rock-water-carbon interactions, organic synthesis on Earth, and steps to life; 4 Life and habitability; 5 Biosignatures as facilitating life detection. On 9 DecemberNASA reported that, based on evidence from Curiosity studying Aeolis PalusGale Crater contained an ancient freshwater lake which could have been a hospitable environment for microbial life. The European Space Agency is currently collaborating with the Russian Federal Space Agency Roscosmos and developing the ExoMars astrobiology rover, which An Introduction to Astrobiology scheduled to be launched in Julybut was postponed to When looking for life on other planets like Earth, some simplifying assumptions are useful to reduce the size of the task of the astrobiologist. One is the informed assumption that the vast majority of life forms in our galaxy are based on carbon chemistriesas are all life forms on Earth. Carbon is the An Introduction to Astrobiology most abundant element in the universe and the energy required to make or break a bond is at just the appropriate level for building molecules which are not only stable, but also reactive. The fact that carbon atoms bond readily to other carbon atoms allows for the building of extremely long and complex molecules. The presence of liquid water is an assumed requirement, as it is An Introduction to Astrobiology common molecule and provides an excellent environment for the formation of complicated carbon-based molecules that could eventually lead to the emergence of life. A third assumption is to focus on planets orbiting Sun -like stars for increased probabilities of planetary An Introduction to Astrobiology. Very small stars provide so little heat and warmth that only planets in very close orbits around them would not be frozen solid, and in such close orbits these planets would be tidally "locked" to the star. This is significant, as red dwarfs are extremely common. See Habitability of red dwarf systems. Since Earth is the only planet known to harbor lifethere is no evident way to An Introduction to Astrobiology if any of these simplifying assumptions are correct. Research on communication with extraterrestrial intelligence CETI focuses on composing and deciphering messages that could theoretically be understood by another technological civilization. Communication attempts by humans have included broadcasting mathematical languages, pictorial systems such as the Arecibo message and computational approaches to detecting and deciphering 'natural' language communication. The SETI program, for example, uses both radio telescopes and optical telescopes to search for deliberate signals from an extraterrestrial intelligence. While some high-profile scientists, such as Carl Saganhave advocated the transmission of messages, [54] [55] scientist Stephen Hawking warned against it, suggesting that aliens might simply raid Earth for its resources and then move on. Most astronomy-related astrobiology research falls into the category of extrasolar planet exoplanet detection, the hypothesis being that if life arose on Earth, then it could also arise on other planets with similar characteristics. The goal of these missions is not only to detect Earth-sized planets but also to directly detect light from the planet so that it may be studied An Introduction to Astrobiology. Given this knowledge, it may be possible to assess the likelihood of life being found on that planet. It is hoped that once these missions come online, their spectra can be cross-checked with these virtual planetary spectra for features that might indicate the presence of life. An estimate for the number of planets with intelligent communicative An Introduction to Astrobiology life can be gleaned from the Drake equationessentially an equation expressing the probability of intelligent life as the product of factors such as the fraction of planets that might be habitable and the fraction of planets on which life An Introduction to Astrobiology arise: [60]. However, whilst the rationale behind the equation is sound, it is unlikely that the equation will be constrained to reasonable limits of error any time soon. The problem with the formula is that it is not used to generate or support hypotheses because it contains factors that can never be verified. The second and third terms, f pstars with planets and f eplanets with habitable conditions, are being evaluated for the star's neighborhood. Drake originally formulated the equation merely as an agenda for discussion at An Introduction to Astrobiology Green Bank conference, [61] but some applications of the formula had been taken literally and related to simplistic or pseudoscientific arguments. Another active research area in astrobiology is planetary system formation. It has been suggested that the peculiarities of the Solar System for example, the presence of Jupiter as a protective shield [63] may have greatly increased the probability of intelligent life arising on our planet. Biology cannot state that a process or phenomenon, by being mathematically possible, has to exist forcibly in an extraterrestrial body. Biologists specify what is speculative and what is not. Until the An Introduction to Astrobiology, life was thought to be entirely dependent on energy from the Sun. An Introduction to Astrobiology on Earth's surface capture energy from sunlight to photosynthesize sugars from carbon dioxide and water, releasing oxygen in the process that is then consumed by oxygen-respiring organisms,