The Planets Their Origin And Development By Harold C Urey

This is a study based on observation rather than mathematical theory in which an attempt is made to discover facts and relationships that give evidence about the course of solar evolution. The author's principle conclusions are that the earth and other territorial planets were formed at much lower temperatures than has generally been supposed; and that a more uniform distribution of iron throughout the silicate phases of the Earth existed in the past than exist now while the iron core of the Earth has been formed at least partly during geological time. For convenience of discussion the author divides the course of planetary evolution into five stages: stage 1 is assumed to start with an interstellar dust cloud, such as the globes of Bok and Reill; stage 2 he calls the preprotoplanet and protoplanet phase, when temperatures had risen to their present levels; stage 3 is the "high temperature stage", and stage 4 is the second low temperature stage; in his final stage the author outlines possible origins for the atmospheres of the earth, Venus and Mars. It may at first surprise that a physical chemist should write a book on the origin and development of the planets. But as the physical problems are many and involved and as the evidence in regard to them is very detailed, the physical chemist can obviously make valuable contributions to this subject. Mr Urey has discussed his views with astronomers, physicists, geophysicists and many other experts and frequently made use of their critical appreciation.

Harold C. Urey (1893–1981), whose discoveries lie at the foundation of modern science, was one of the most famous American scientists of the twentieth century. Born in rural Indiana, his evolution from small-town farm boy to scientific celebrity made him a symbol and spokesman for American scientific authority. Because he rose to fame alongside the prestige of American science, the story of his life reflects broader changes in the social and intellectual landscape of twentieth-century America. In this, the first ever biography of the chemist, Matthew Shindell shines new light on Urey’s struggles and achievements in a thoughtful exploration of the science, politics, and society of the Cold War era. From Urey’s orthodox religious upbringing to his death in 1981, Shindell follows the scientist through nearly a century of American history: his discovery of deuterium and heavy water earned him the Nobel Prize in 1934, his work on the Manhattan Project helped usher in the atomic age, he initiated a generation of American scientists into the world of quantum physics and chemistry, and he took on the origin of the Moon in NASA’s lunar exploration program. Despite his success, however, Urey had difficulty navigating the nuclear age. In later years he lived in the shadow of the bomb he helped create, plagued by the uncertainties unleashed by the rise of American science and unable to reconcile the consequences of scientific progress with the morality of religion. Tracing Urey’s life through two world wars and the Cold War not only conveys the complex historical relationship between science and religion in the twentieth century, but it also illustrates how these complexities spilled over into the early days of space science. More than a life story, this book immerses readers in the trials and triumphs of an extraordinary man and his extraordinary times.

The Moon is the most viewed object in the sky, the Sun being too bright to look at directly and the planets too far away. The Greeks deduced everything that could be learned about the Moon using only the naked eye, including that it has no light of its own but reflects that of the Sun. They understood the cause of eclipses and used the Earth's shadow on the Moon to conclude that our planet is a sphere and to calculate the size of both the Moon and the Earth. The invention of the telescope some two millennia later offered the opportunity for much greater understanding, but the early observers became sidetracked onto a dead end: First, they fooled themselves into believing that they saw evidence of life on the Moon, even the works of a civilization. Second, they became convinced that the craters of the Moon were volcanoes like those we have on the Earth. These wrong-headed beliefs took centuries to dispel. The origin of the Moon itself has proven an even more difficult question, but scientists have now closed in on the answer. They find that our placid and seemingly unchanging Moon was born in colossal violence as a planet the size of Mars crashed into the primordial Earth and flung off a blob that solidified to become our heavenly companion. Unlocking the Moon's Secrets follows these developments to show how science evolves, complete with misunderstandings, contentious arguments, difficult to relinquish assumptions, and shifting views as new facts come to light. Thanks to the work of generations of determined scientists, we understand our Moon, at last.

This monograph is based on four papers which have been published in Astrophysics and Space Sciences 1970--1974. They contain the results of our joint work started in 1968 at the University of California, San Diego, in La Jolla. The work was based on the belief that the complicated processes by which our solar system was formed can only be clarified by close collaboration between representatives of the physical and chemical sciences. Our investigations have also been strongly supported by work at other institu tions, especially by a group at the Royal Institute of Technology, Stockholm, where a number of plasma experiments have been made in order to clarify basic processes which are relevant to cosmogonic problems. These experiments were, in their turn inspired by theoretical work on primordial processes carried out during the last thirty-five years. We especially want to acknowledge the contributions by Drs N. Herlofson, B. Lehnert, C.-G. Fiilthammar, and Lars Danielsson in Stockholm and by Drs J.

Ranked as one of the half-dozen top biologists of the U.S. in a 1939 Time magazine cover story, Dr. Oscar Riddle was one of the world's foremost experts on the pituitary gland, biology, and evolution. Riddle's thought-provoking and explosive text examines the tension between evolutionary thought and organized religions as he traces the evolutionary process from atoms to man and society.

"Exploring the unknown" is a multi-volume series containing a selection of key documents in the history of the U.S. civil space program. Volume V, focusing on the exploration of space by robotic spacecraft that have significantly altered our perspectives on the cosmos, prints 121 key documents on the history of space science, planetary exploration of the solar system, and space astrophysics, edited for ease of use. Many of these documents are published here for the first time. Each is introduced by a headnote providing context, bibliographical information, and background information necessary to understanding the document. This documentary history is an essential reference for anyone interested in the history of the U.S. civil space program and its development over time. It will serve as a valuable source both for students and scholars. Additional volumes will appear later that trace space science and the programmatic developments in the history of the U.S. exploration of space.