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Readingsample The New Cosmos An Introduction to Astronomy and Astrophysics Bearbeitet von Albrecht Unsöld, Bodo Baschek Neuausgabe 2005. Buch. xiv, 562 S. Hardcover ISBN 978 3 540 67877 9 Format (B x L): 21 x 28 cm Gewicht: 1820 g Weitere Fachgebiete > Physik, Astronomie > Angewandte Physik > Astrophysik Zu Inhaltsverzeichnis schnell und portofrei erhältlich bei Die Online-Fachbuchhandlung beck-shop.de ist spezialisiert auf Fachbücher, insbesondere Recht, Steuern und Wirtschaft. Im Sortiment finden Sie alle Medien (Bücher, Zeitschriften, CDs, eBooks, etc.) aller Verlage. Ergänzt wird das Programm durch Services wie Neuerscheinungsdienst oder Zusammenstellungen von Büchern zu Sonderpreisen. Der Shop führt mehr als 8 Millionen Produkte. 1 1. Introduction Astronomy, the study of the stars and other celestial telescope, and of space travel, allowing observations to objects, is one of the exact sciences. It deals with the be made over the entire range of the electromagnetic quantitative investigation of the cosmos and the physical spectrum. laws which govern it: with the motions, the structures, In the 19th and particularly in the 20th centuries, the formation, and the evolution of the various celestial physics assumed the decisive role in the elucidation bodies. of astronomical phenomena; astrophysics has steadily Astronomy is among the oldest of the sciences. The increased in importance over “classical astronomy”. earliest human cultures made use of their knowledge of There is an extremely fruitful interaction between as- celestial phenomena and collected astronomical data in trophysics/astronomy and physics: on the one hand, order to establish a calendar, measure time, and as an aid astronomy can be considered to be the physics of the to navigation. This early astronomy was often closely cosmos, and there is hardly a discipline in physics which interwoven with magical, mythological, religious, and does not find application in modern astronomy; on the philosophical ideas. other hand, the cosmos with its often extreme states of The study of the cosmos in the modern sense, matter offers the opportunity to study physical processes however, dates back only to the ancient Greeks: the under conditions which are unattainable in the labora- determination of distances on the Earth and of positions tory. Along with physics, and of course mathematics, of the celestial bodies in the sky, together with know- applications of chemistry and the Earth and biological ledge of geometry, led to the first realistic estimates of sciences are also of importance in astronomy. the sizes and distances of the objects in outer space. The Among the sciences, astronomy is unique in that no complex orbits of the Sun, the Moon, and the planets experiments can be carried out on the distant celes- were described in a mathematical, kinematical picture, tial objects; astronomers must content themselves with which allowed the calculation of the positions of the observations. “Diagnosis from a distance”, and in par- planets in advance. Greek astronomy attained its zenith, ticular the quantitative analysis of radiation from the and experienced its swan song, in the impressive work cosmos over the widest possible spectral range, thus of Ptolemy, about 150 a.D. The name of the science, as- play a central role in astronomical research. tronomy, is quite appropriately derived from the Greek The rapid development of many branches of astron- word “αστηρ” = staror“αστρoν” = constellation or omy has continued up to the present time. With this heavenly body. revised edition of The New Cosmos,wehavetriedto At the beginning of the modern period, in the 16th keep pace with the rapid expansion of astronomical and 17th centuries, the Copernican view of the universe knowledge while maintaining our goal of providing became generally accepted. Celestial mechanics re- a comprehensive – and comprehensible – introduc- ceived its foundation in Newton’s Theory of Gravitation tory survey of the whole field of astronomy. We have in the 17th century and was completed mathematically placed emphasis on observations of the manifold ob- in the period immediately following. Major progress in jects and phenomena in the cosmos, as well as on the astronomical research was made in this period, on the basic ideas which provide the foundation for the var- one hand through the introduction of new concepts and ious fields within the discipline. We have combined theoretical approaches, and on the other through ob- description of the observations as directly as possible servations of new celestial phenomena. The latter were with the theoretical approaches to their elucidation. Par- made possible by the development of new instruments. ticular results, as well as information from physics and The invention of the telescope at the beginning of the the other natural sciences which are required for the 17th century led to a nearly unimaginable increase in understanding of astronomical phenomena, are, how- the scope of astronomical knowledge. Later, new eras ever, often simply stated without detailed explanations. in astronomical research were opened up by the devel- The complete bibliography, together with a list of im- opment of photography, of the spectrograph, the radio portant reference works, journals, etc., is intended to 1. Introduction 2 help the reader to gain access to the more detailed and The treatment of the physics of individual stars occupies specialized literature. an important place in Part III. Along with the theory of We begin our study of the cosmos, its structure and radiation, atomic spectroscopy in particular forms the its laws, “at home” by considering our Solar System in basis for quantitative investigation of the radiation and Part I, along with classical astronomy. This part, like the the spectra of the Sun and other stars, and for the un- three following parts, starts with a historical summary derstanding of the physical-chemical structure of their which is intended to give the reader an overview of the outer layers, the stellar atmospheres. Understanding of subject. We first become acquainted with observations the mechanism of energy release by thermonuclear reac- of the heavens and with the motions of the Earth, the tions and by gravitation is of decisive importance for the Sun, and the Moon, and introduce celestial coordinates study of stellar interiors, their structures and evolution. and sidereal time. The apparent motions of the planets We then discuss the development of the stars of the and other objects are then explained in the framework of main sequence, which includes the phase of intensive the Newtonian Theory of Gravitation. Before consider- stellar hydrogen burning, continuing to their final stages ing the planets and other objects in the Solar System in (white dwarf, neutron star or black hole). The forma- detail, we give a summary of the development of space tion of stars and their earliest development are treated research, which has contributed enormously to know- in the following sections in connection with the inter- ledge of our planetary system. Part I ends with a discus- stellar material in our galaxy. At the end of Part III, we sion of the individual planets, their moons, and other deal with strong gravitational fields, which we describe smaller bodies such as asteroids, comets and meteors. in the framework of Einstein’s General Relativity the- Prior to taking up the topic of the Sun and other ory; here, we concentrate in particular on black holes, stars, it is appropriate to describe the basic principles gravitational lenses, and gravitational waves. of astronomical observation methods, and we do this in In Part IV, we take up stellar systems and the macro- Part II. An impressive arsenal of telescopes and detec- scopic structure of the universe. Making use of our tors is available to today’s astronomer; with them, from knowledge of individual stars and their distances from the Earth or from space vehicles, he or she can inves- the Earth, we first develop a picture of stellar clusters tigate the radiation emitted by celestial bodies over the and stellar associations. We then discuss the interstellar entire range of the electromagnetic spectrum, from the matter which consists of tenuous gas and dust clouds, radio and microwave regions through the infrared, the and treat star formation. Finally, we develop a picture visible, and the ultraviolet to the realm of highly ener- of our own Milky Way galaxy, to which the Sun be- getic radiations, the X-rays and gamma rays. The use longs together with about 100 million other stars. We of computers provides an essential tool for the modern treat the distribution and the motions of the stars and astronomer in these observations. star clusters and of the interstellar matter. After mak- Part III is devoted to stars, which we first treat as in- ing the acquaintance of methods for the determination dividual objects. We give an overview of the different of the enormous distances in intergalactic space, we types of stars such as those of the main sequence, gi- turn to other galaxies, among which we find a variety ants and supergiants, brown dwarfs, white dwarfs and of types: spiral and elliptical galaxies, infrared and star- neutron stars, as well as the great variety of variable burst galaxies, radio galaxies, and the distant quasars. In stars (Cepheids, magnetic stars, novas, supernovas, pul- the centers of many galaxies, we observe an “activity” sars, gamma sources ...) and of stellar activity, and involving the appearance of extremely large
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