Book contents
- Frontmatter
- EDITOR'S PREFACE
- PREFACE
- Contents
- LIST OF ILLUSTRATIONS
- CHAPTER I BELIEFS AND SUPERSTITIONS RELATIVE TO COMETS
- CHAPTER II COMETARY ASTRONOMY UP TO THE TIME OF NEWTON
- CHAPTER III THE MOTIONS AND ORBITS OF COMETS
- SECTION I COMETS PARTICIPATE IN THE DIURNAL MOTION
- SECTION II MOTIONS OF COMETS
- SECTION III IRREGULARITIES IN THE MOTIONS OF COMETS
- SECTION IV THE ORBITS OF COMETS
- SECTION V THE ORBITS OF COMETS COMPARED WITH THE ORBITS OF THE PLANETS
- SECTION VI DETERMINATION OF THE PARABOLIC ORBIT OF A COMET
- CHAPTER IV PERIODICAL COMETS
- CHAPTER V PERIODICAL COMETS
- CHAPTER VI THE WORLD OF COMETS AND COMETARY SYSTEMS
- CHAPTER VII PHYSICAL AND CHEMICAL CONSTITUTION OF COMETS
- CHAPTER VIII PHYSICAL TRANSFORMATIONS OF COMETS
- CHAPTER IX MASS AND DENSITY OF COMETS
- CHAPTER X THE LIGHT OF COMETS
- CHAPTER XI THEORY OF COMETARY PHENOMENA
- CHAPTER XII COMETS AND SHOOTING STARS
- CHAPTER XIII COMETS AND THE EARTH
- CHAPTER XIV PHYSICAL INFLUENCES OF COMETS
- CHAPTER XV SOME QUESTIONS ABOUT COMETS
- I ELLIPTIC ELEMENTS OF THE RECOGNISED PERIODICAL COMETS OF THE SOLAR SYSTEM
- II GENERAL CATALOGUE OF THE ORBITS OF COMETS
- Plate section
SECTION II - MOTIONS OF COMETS
Published online by Cambridge University Press: 05 March 2012
- Frontmatter
- EDITOR'S PREFACE
- PREFACE
- Contents
- LIST OF ILLUSTRATIONS
- CHAPTER I BELIEFS AND SUPERSTITIONS RELATIVE TO COMETS
- CHAPTER II COMETARY ASTRONOMY UP TO THE TIME OF NEWTON
- CHAPTER III THE MOTIONS AND ORBITS OF COMETS
- SECTION I COMETS PARTICIPATE IN THE DIURNAL MOTION
- SECTION II MOTIONS OF COMETS
- SECTION III IRREGULARITIES IN THE MOTIONS OF COMETS
- SECTION IV THE ORBITS OF COMETS
- SECTION V THE ORBITS OF COMETS COMPARED WITH THE ORBITS OF THE PLANETS
- SECTION VI DETERMINATION OF THE PARABOLIC ORBIT OF A COMET
- CHAPTER IV PERIODICAL COMETS
- CHAPTER V PERIODICAL COMETS
- CHAPTER VI THE WORLD OF COMETS AND COMETARY SYSTEMS
- CHAPTER VII PHYSICAL AND CHEMICAL CONSTITUTION OF COMETS
- CHAPTER VIII PHYSICAL TRANSFORMATIONS OF COMETS
- CHAPTER IX MASS AND DENSITY OF COMETS
- CHAPTER X THE LIGHT OF COMETS
- CHAPTER XI THEORY OF COMETARY PHENOMENA
- CHAPTER XII COMETS AND SHOOTING STARS
- CHAPTER XIII COMETS AND THE EARTH
- CHAPTER XIV PHYSICAL INFLUENCES OF COMETS
- CHAPTER XV SOME QUESTIONS ABOUT COMETS
- I ELLIPTIC ELEMENTS OF THE RECOGNISED PERIODICAL COMETS OF THE SOLAR SYSTEM
- II GENERAL CATALOGUE OF THE ORBITS OF COMETS
- Plate section
Summary
Distinction between cometa, nebulæ, and temporary stars–Comets, in their motions, are subject to stationary periods and retrogressions–The apparent complications arise, as in the case of the planets, from the simultaneous movement of these bodies and the earth.
There is nothing in the foregoing section to distinguish comets from the multitude of brilliant stars which nightly illuminate the azure vault of heaven. Comets, it is true, appear in regions where before they had not been visible, and after a time they disappear; but in this respect they resemble those remarkable stars which have been seen to shine out suddenly in the midst of a constellation, to increase in brilliancy for a time, and afterwards to become faint and disappear; such as the famous temporary stars of 1572 (the Pilgrim), 1604, 1670, and 1866, which appeared and became extinct in the constellations of Cassiopeia, Serpens, Vulpecula, and Corona Borealis respectively. These stars, however, have, without exception, been distinguished by this peculiarity, that from the first to the last day of their apparition they continued immovable in the spot where they first appeared; or, more correctly, that their only motion was that due to the diurnal revolution of the heavens. Situated, like the fixed stars, at immense distances from our system, they had no appreciable movement of their own during the whole time of their visibility–in some instances of considerable duration. The same is true of the nebulæ, which are distinguished from comets by the fact of their immobility.
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- The World of Comets , pp. 61 - 64Publisher: Cambridge University PressPrint publication year: 2010First published in: 1877