Books on the topic 'Orbital Collisions'

This is an advance summary of a forthcoming article in the Oxford Encyclopedia of Planetary Science. Please check back later for the full article.The Austrian Outer Space Act, which entered into force in December 2011; and the Austrian Outer Space Regulation, which has been in force since February 2015, form the legal framework for Austrian national space activities. The elaboration of national space legislation became necessary to ensure compliance with Austria’s obligations as State Party to the five United Nations Space Treaties when the first two Austrian satellites were launched in 2012 and Austria became a launching state on its own. The legislation comprehensively regulates legal aspects related to space activities, such as authorization, supervision, and termination of space activities; registration and transfer of space objects; recourse of the government against the operator; as well as implementation of the law and sanctions for its infringement. One of the main purposes of the law is to ensure the authorization of national space activities. The Outer Space Act sets forth the main conditions for authorization, which inter alia refer to the expertise of the operator; requirements for orbital positions and frequency assignments; space debris mitigation, insurance requirements, and the safeguard of public order; public health; national security as well as Austrian foreign policy interests; and international law obligations. The Austrian Outer Space Regulation complements these provisions by specifying the documents the operator must submit as evidence of the fulfillment of the authorization conditions, which include the results of safety tests, emergency plans, and information on the collection and use of Earth observation data. Particular importance is attached to the mitigation of space debris. Operators are required to take measures in accordance with international space debris mitigation guidelines for the avoidance of operational debris, the prevention of on-orbit break-ups and collisions, and the removal of space objects from Earth orbit after the end of the mission. Another specificity of the Austrian space legislation is the possibility of an exemption from the insurance requirement or a reduction of the insurance sum, if the space activity is in the public interest. This allows support to space activities that serve science, research, and education. Moreover, the law also provides for the establishment of a national registry for objects launched into outer space by the competent Austrian Ministry. The first two Austrian satellites have been entered into this registry after their launch in 2012. The third Austrian satellite, launched in June 2017, will be the first satellite authorized under the Austrian space legislation.

This is an advance summary of a forthcoming article in the Oxford Encyclopedia of Planetary Science. Please check back later for the full article.Space debris has grown to be a significant problem for outer space activities. The remnants of human activities in space are very diverse; they can be tiny paint flakes, all sorts of fragments, or entirely intact—but otherwise nonfunctional spacecraft and rocket bodies. The amount of debris is increasing at a growing pace, thus raising the risk of collision with operational satellites. Due to the relative high velocities involved in on-orbit collisions, their consequences are severe; collisions lead to significant damage or the complete destruction of the affected spacecraft. Protective measures and collision avoidance have thus become a major concern for spacecraft operators. The pollution of space with debris must, however, not only be seen as an unfavorable circumstance that accompanies space activities and increases the costs and complexity of outer space activities. Beyond this rather technical perspective, the presence of man-made, nonfunctional objects in space represents a global environmental concern. Similar to the patterns of other environmental problems on Earth, debris generation appears to have surpassed the absorption capacity of the space environment. Studies indicate that the evolution of the space object environment has crossed the tipping point to a runaway situation in which an increasing number of collisions―mostly among debris―leads to an uncontrolled population growth. It is thus in the interest of all mankind to address the debris problem in order to preserve the space environment for future generations.International space law protects the space environment. Article IX of the Outer Space Treaty obligates States to avoid the harmful contamination of outer space. The provision corresponds to the obligation to protect the environment in areas beyond national jurisdiction under the customary “no harm” rule of general environmental law. These norms are applicable to space debris and establish the duty not to pollute outer space by limiting the generation of debris. They become all the more effective when the principles of sustainable development are taken into account, which infuse considerations of intra- as well as inter-generational justice into international law. In view of the growing debris pollution and its related detrimental effects, it is obvious that questions of liability and responsibility will become increasingly relevant. The Liability Convention offers a remedy for victims having suffered damage caused by space debris. The launching State liability that it establishes is even absolute for damage occurring on the surface of the Earth. The secondary rules of international responsibility law go beyond mere compensation: States can also be held accountable for the environmental pollution event itself, entailing a number of consequential obligations, among them―under certain circumstances―a duty to active debris removal. While international law is, therefore, generally effective in addressing the debris problem, growing use and growing risks necessitate the establishment of a comprehensive traffic management regime for outer space. It would strengthen the rule of law in outer space and ensure the sustainability of space utilization.

Hegel’s Philosophy of Nature is best understood through its contribution to Hegel’s larger philosophical project of both articulating and actually achieving human freedom. It contributes to this project by showing that nature and natural things are themselves free, in a specific sense of freedom that Hegel critically appropriates from Kant. Hegel demonstrates this freedom of nature through the conceptual transformation of natural-scientific “representations” (laws, kinds, and other universals) into systematically ordered “concrete universals” in which the empirical content of the sciences is preserved and systematized in a way that emphasizes nature’s self-determination, rather than its alleged sheer givenness and “externality.” After a general account of, first, Hegel’s understanding of the natural sciences and their results, and, second, his transformative method, the chapter presents a detailed reconstruction of his treatment of collision, fall, and orbital motion in the Mechanics.

Most scientists now agree that some sixty-five million years ago, an immense comet slammed into the Yucatan, detonating a blast twenty million times more powerful than the largest hydrogen bomb, punching a hole ten miles deep in the earth. Trillions of tons of rock were vaporized and launched into the atmosphere. For a thousand miles in all directions, vegetation burst into flames. There were tremendous blast waves, searing winds, showers of molten matter from the sky, earthquakes, and a terrible darkness that cut out sunlight for a year, enveloping the planet in freezing cold. Thousands of species of plants and animals were obliterated, including the dinosaurs, some of which may have become extinct in a matter of hours. In Impact, Gerrit L. Verschuur offers an eye-opening look at such catastrophic collisions with our planet. Perhaps more important, he paints an unsettling portrait of the possibility of new collisions with earth, exploring potential threats to our planet and describing what scientists are doing right now to prepare for this awful possibility. Every day something from space hits our planet, Verschuur reveals. In fact, about 10,000 tons of space debris fall to earth every year, mostly in meteoric form. The author recounts spectacular recent sightings, such as over Allende, Mexico, in 1969, when a fireball showered the region with four tons of fragments, and the twenty-six pound meteor that went through the trunk of a red Chevy Malibu in Peekskill, New York, in 1992 (the meteor was subsequently sold for $69,000 and the car itself fetched $10,000). But meteors are not the greatest threat to life on earth, the author points out. The major threats are asteroids and comets. The reader discovers that astronomers have located some 350 NEAs ("Near Earth Asteroids"), objects whose orbits cross the orbit of the earth, the largest of which are 1627 Ivar (6 kilometers wide) and 1580 Betula (8 kilometers). Indeed, we learn that in 1989, a bus-sized asteroid called Asclepius missed our planet by 650,000 kilometers (a mere six hours), and that in 1994 a sixty-foot object passed within 180,000 kilometers, half the distance to the moon. Comets, of course, are even more deadly. Verschuur provides a gripping description of the small comet that exploded in the atmosphere above the Tunguska River valley in Siberia, in 1908, in a blinding flash visible for several thousand miles (every tree within sixty miles of ground zero was flattened). He discusses Comet Swift-Tuttle--"the most dangerous object in the solar system"--a comet far larger than the one that killed off the dinosaurs, due to pass through earth's orbit in the year 2126. And he recounts the collision of Comet Shoemaker-Levy 9 with Jupiter in 1994, as some twenty cometary fragments struck the giant planet over the course of several days, casting titanic plumes out into space (when Fragment G hit, it outshone the planet on the infrared band, and left a dark area at the impact site larger than the Great Red Spot). In addition, the author describes the efforts of Spacewatch and other groups to locate NEAs, and evaluates the idea that comet and asteroid impacts have been an underrated factor in the evolution of life on earth. Astronomer Herbert Howe observed in 1897: "While there are not definite data to reason from, it is believed that an encounter with the nucleus of one of the largest comets is not to be desired." As Verschuur shows in Impact, we now have substantial data with which to support Howe's tongue-in-cheek remark. Whether discussing monumental tsunamis or the innumerable comets in the Solar System, this book will enthrall anyone curious about outer space, remarkable natural phenomenon, or the future of the planet earth.

In quantum statistics based on many-body Green’s functions, the effective medium is represented by the selfenergy. This book aims to discuss the selfenergy from this point of view. The knowledge of the exact selfenergy is equivalent to the knowledge of the exact correlation function from which one can evaluate any single-particle observable. Complete interpretations of the selfenergy are as rich as the properties of the many-body systems. It will be shown that classical features are helpful to understand the selfenergy, but in many cases we have to include additional aspects describing the internal dynamics of the interaction. The inductive presentation introduces the concept of Ludwig Boltzmann to describe correlations by the scattering of many particles from elementary principles up to refined approximations of many-body quantum systems. The ultimate goal is to contribute to the understanding of the time-dependent formation of correlations. Within this book an up-to-date most simple formalism of nonequilibrium Green’s functions is presented to cover different applications ranging from solid state physics (impurity scattering, semiconductor, superconductivity, Bose–Einstein condensation, spin-orbit coupled systems), plasma physics (screening, transport in magnetic fields), cold atoms in optical lattices up to nuclear reactions (heavy-ion collisions). Both possibilities are provided, to learn the quantum kinetic theory in terms of Green’s functions from the basics using experiences with phenomena, and experienced researchers can find a framework to develop and to apply the quantum many-body theory straight to versatile phenomena.