The Universal Book of Astronomy

David Darling

Description

The ultimate guide to the final frontier

This alphabetical tour of the universe provides all the history, science, and up-to-the-minute facts needed to explore the skies with authority. Packed with more than 3,000 entries that cover everything from major observatories and space telescopes to biographies of astronomers throughout the ages, it showcases an extraordinary array of newfound wonders, including microquasars, brown dwarfs, and dark energy, as well as a host of individual comets, asteroids, moons, planets, stars, nebulas, and galaxies. Featuring nearly 200 illustrations and eight pages of color photographs, this comprehensive guide provides easy lookup of topics and offers more in-depth information than can be found in existing star guides or astronomy dictionaries. It's an ideal resource for the amateur astronomer or anyone with an interest in the mysteries of the cosmos.

David Darling, PhD (Brainerd, MN), is the author of The Complete Book of Spaceflight and Equations of Eternity, a New York Times Notable Book.

Sujets

• Astronomie
• Astrophysique
• Science
• David Darling
• Astronomy
• Sciences et techniques
• Space Science

Informations

• Publié par: Turner Publishing Company
• Date de parution: 01 octobre 2003
• Nombre de lectures: 0
• EAN13: 9781620455982
• Langue: English
• Poids de l'ouvrage: 5 Mo

Extrait

The Universal Book of Astronomy
The Universal Book of Astronomy
From the Andromeda Galaxy to the Zone of Avoidance
David Darling
WILEY
John Wiley Sons, Inc. -->
This book is printed on acid-free paper.
Copyright 2004 by David Darling. All rights reserved
Published by John Wiley Sons, Inc., Hoboken, New Jersey
Published simultaneously in Canada
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Library of Congress Cataloging-in-Publication Data:
Darling, David J.
The universal book of astronomy from the Andromeda Galaxy to the zone of avoidance / David Darling.
p. cm.
Includes bibliographical references and index.
ISBN 0-471-26569-1
1. Astronomy-Dictionaries. I. Title.
QB14. D37 2003
520'.3-dc21
2003013941
Printed in the United States of America
10 9 8 7 6 5 4 3 2 1
Contents
Introduction How to Use This Book Exponential Notation Units Astronomy Entries A to Z Star Charts Category Index
Introduction

The universe has sprung many remarkable surprises on us in the past few years. Scores of planets have been detected around other stars. Vast amounts of ice and evidence for recent liquid water have been found on Mars. Brown dwarfs, medium-sized black holes, giant Centaurs, ultra-luminous clusters, microquasars, and magnetars have been added to an already extraordinary cosmic menagerie. Dark energy has joined dark matter as a likely chief ingredient of the universe, which, against all expectations, seems to be gathering pace in its headlong outward rush. We have seen the surface of the Sun, the center of our galaxy, and the environs of dying stars in unprecedented, awe-inspiring detail. We have begun to make out the great filaments of galaxy clusters and the gaping voids that are the largest of cosmic structures.
We are lucky to find ourselves in a world of such wonders at a time when they are being revealed by powerful new instruments-the enhanced Hubble Space Telescope, the Very Large Telescope, the Chandra X-ray Observatory, and others. Yet the breakthroughs are coming so thick and fast that it is hard, even for professional astronomers let alone the interested layperson, to keep track of them. This book is intended as a comprehensive, user-friendly guide to the cosmos of the early twenty-first century. By including the latest results and conjectures alongside well-established theory and facts, and by extensive cross-referencing, it offers a way for everyone, from the nonspecialist to the seasoned researcher, to gain a better grasp of the modern universe. And grasp it we should because we are all part of this astonishing creation-our very bodies fashioned of atoms that were made inside giant stars long ago. Bring only your imagination and the courage needed to gaze up and out across 15 billion light-years!
How to Use This Book

Entries range from short definitions to lengthy articles on topics of major importance or unusual interest, and are extensively cross-referenced. They are arranged alphabetically according to the first word of the entry name. So, for example, "BL Herculis star" precedes "black dwarf." Terms that appear in bold type have their own entries. Metric units are used throughout, unless it is more appropriate, for historical reasons, to do otherwise. See the "Units" section that follows for conversion factors. Star charts are included at the back of the book to show the position of bright stars and other celestial objects. Readers are invited to visit the author's web site at www.daviddarling.info for breaking news in astronomy and related subjects.
Exponential Notation
In the interest of brevity, exponential notation is used in this book to represent large and small numbers. For example, 300,000,000 is written as 3 10 8 , the power of 10 indicating how many places the decimal point has been moved to the left from the original number (or, more simply, the number of zeroes). Small numbers have negative exponents, indicating how many places the point has been shifted to the left. For example, 0.000049 is written as 4.9 10 5 .
Units
Distance
1 kilometer (km) = 0.62 miles
1 meter (m) = 3.28 feet (ft) = 39.37 inches (in.)
1 centimeter (cm) = 0.39 in.
1 m = 1,000 millimeters (mm) = 10 6 micrometers (microns, or m)
1 angstrom ( ) = 0.1 nanometer (nm) = 10 10 m
1 astronomical unit (AU) = 1.50 10 8 km (the mean Earth-Sun distance)
1 light-year = 63,240 AU = 9.46 10 12 km
1 parsec (pc) = 3.2616 light-years = 206,260 AU = 3.0857 10 13 km
Angle
1 degree ( ) = 60 arcminutes (') = 3,600 arcseconds (")
1 arcsecond = 1,000 milliarcsec = 10 6 microarcsec
Speed
1 km/s = 2,240 mph
Mass
1 kilogram (kg) = 2.21 pounds (lb)
1 metric ton = 1,000 kg = 2,205 lb = 0.98 long ton
M sun = 1.989 10 30 kg = 1,047 M Jupiter = 332,958 M Earth
Note: In this book, tons refer to metric tons.
Force
1 newton (N) = 0.22 pounds-force (lbf) = 0.102
kilograms-force (kgf)
Pressure
1 bar = 0.987 atmosphere = 101,300 pascals = 14.5
lb/square inch = 100,000 N/m 2
Energy
1 joule (J) = 9.48 10 4 British thermal unit (Btu)
1 electron-volt (eV) = 1.60 10 19 J
1 GeV = 10 3 MeV = 10 6 keV = 10 9 eV
Note: Electron-volts are convenient units for measuring the energies of particles and electromagnetic radiation. In the case of electromagnetic radiation, it is customary to measure longer-wavelength types in terms of their wavelength (in units of cm, m, , etc.) and shorter-wavelength types, especially X rays and gamma-rays, in terms of their energy (in units of keV, MeV, etc.). The wavelength associated with electromagnetic waves of energy 1 keV is 0.124 nm.
Temperature
C = 5/9 (F 32)
F = 9/5 C + 32
0K = 273.16 C
1K increase = 1 C increase
A

A star
A star of spectral type A, white in color, with a spectrum dominated by the Balmer series of hydrogen. Lines of heavy elements, such as iron, are noticeable at the cooler end of the range. Main sequence A stars have surface temperatures of 7,500 to 9,900 K, luminosities of 7 to 80 L sun , and masses of 1.5 to 3 M sun ; familiar examples include Sirius, Vega , and Altair . A-type supergiants , such as Deneb , may be as hot as 11,000 K and have masses up to 20 M sun and luminosities of more than 35,000 L sun . Among A-type peculiar star s are Ae star s, Am star s, and Ap stars . Also, two of the main kinds of pulsating variables, RR Lyrae stars and Delta Scuti stars , have surface temperatures in the A-star range.
Aaronson, Marc (1950-1987)
A talented young American astronomer who was killed in a tragic accident in the dome of the 4-m Mayall Telescope on Kitt Peak. Due to a malfunction of the emergency stop, Aaronson became trapped in the catwalk door of the rotating telescope dome when the outer stepladder closed it. Minor planet (3277) Aaronson is named in his honor.
Abell cluster
A rich cluster of galaxies identified in the Abell Catalog of Rich Clusters of Galaxies , which was the first comprehensive catalog of clusters of galaxies and, in its extended form, is still the largest. The Abell Catalog was first published in 1958 by the American astronomer George Abell (1927-1983), a graduate student at the time, and contained 2,712 clusters of galaxies north of declination 27 identified by Abell from his analysis of the Palomar Observatory Sky Survey photographs. To be included in the Catalog a galaxy cluster had to have at least 50 members in the magnitude range m 3 to m 3 + 2, where m 3 is the magnitude of the third brightest cluster member, within a radius of about 1.5 megaparsecs (just under 5 million light-years). Abell classified such clusters as regular and irregular, and ranked them on 6-point scales according to both their richness (population density) and distance (1 to 6, for closest to farthest). The Catalog proved of seminal importance to extragalactic astronomy, leading to a better understanding of the nature and properties of clusters of galaxies, and the identification of superclusters and large-scale structure . Following the latest (1989) revisions and extensions to include rich cluster