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Chapters: Origin of Water on Earth, Open Problem, List of Unsolved Problems in Biology. Source: Wikipedia. Pages: 18. Not illustrated. Free updates online. Purchase includes a free trial membership in the publisher's book club where you can select from more than a million books without charge. Excerpt: The question of the origin of water on Earth, or more accurately put, the question of why there is clearly more water on the Earth than on the other planets of the Solar System, has not been clarified. There are several acknowledged theories as to how the world's oceans were formed over the past 4.6 billion years. Some of the most likely contributory factors to the origin of the Earth's oceans are as follows: A sizeable quantity of water would have been in the material which formed the Earth. Water molecules would have escaped Earth's gravity more easily when it was less massive during its formation. Hydrogen and helium are expected to continually leak from the atmosphere, but the lack of denser noble gases in the modern atmosphere suggests that something disastrous happened to the early atmosphere. Part of the young planet is theorized to have been disrupted by the impact which created the Moon, which should have caused melting of one or two large areas. Present composition does not match complete melting and it is hard to completely melt and mix huge rock masses. However, a fair fraction of material should have been vaporized by this impact, creating a rock-vapor atmosphere around the young planet. The rock-vapor would have condensed within two thousand years, leaving behind hot volatiles which probably resulted in a heavy carbon dioxide atmosphere with hydrogen and water vapor. Liquid water oceans existed despite the surface temperature of 230°C because of the atmospheric pressure of the heavy CO2 atmosphere. As cooling continued, subduction and dissolving in ocean water removed most CO2 from the atmosphere but levels osci...More: http://booksllc.net/?id=4224324 ... Read more

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This scarce antiquarian book is a selection from Kessinger Publishing's Legacy Reprint Series. Due to its age, it may contain imperfections such as marks, notations, marginalia and flawed pages. Because we believe this work is culturally important, we have made it available as part of our commitment to protecting, preserving, and promoting the world's literature. Kessinger Publishing is the place to find hundreds of thousands of rare and hard-to-find books with something of interest for everyone! ... Read more

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Chapters: Origin of Language, Language Development, Gradient Well-Formedness. Source: Wikipedia. Pages: 42. Not illustrated. Free updates online. Purchase includes a free trial membership in the publisher's book club where you can select from more than a million books without charge. Excerpt: The origin of language, known in linguistics as glottogony refers to the acquisition of the human ability to use language at some point during the Paleolithic. The main difficulty of the question stems from the fact that it concerns a development in deep prehistory which left no direct fossil traces and for which no comparable processes can be observed today. The time range under discussion in this context extends from the phylogenetic separation of Homo and Pan some 5 million years ago to the emergence of full behavioral modernity some 50,000 years ago. The evolution of fully modern human language requires the development of the vocal tract used for speech production and the cognitive abilities required to produce linguistic utterances. The debate surrounds the timeline, sequence and order of developments associated with this. It is mostly undisputed that pre-human australopithecines did not have communication systems significantly different from those found in great apes in general, but scholarly opinions vary as to the developments since the appearance of Homo some 2.5 million years ago. Some scholars assume the development of primitive language-like systems (proto-language) as early as Homo habilis, while others place the development of primitive symbolic communication only with Homo erectus (1.8 million years ago) or Homo heidelbergensis (0.6 million years ago) and the development of language proper with Homo sapiens sapiens less than 100,000 years ago. Many scientists make a distinction between speech and language. They believe that language (as a content of communication, and primarily as a cognitive ability to form concepts and ...More: http://booksllc.net/?id=620396 ... Read more

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Article in the July, 1962 issue of Foreign Affairs Magazine. ... Read more