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
- 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
- SECTION I COMETS PHYSICALLY CONSIDERED
- SECTION II COMETARY NUCLEI, TAILS, AND COMÆ
- SECTION III COMETS DEVOID OF NUCLEUS AND TAIL
- SECTION IV DIRECTION OF THE TAILS OF COMETS
- SECTION V NUMBER OF TAILS
- SECTION VI DIFFERENT FORMS OF TAILS
- SECTION VII LENGTH OF TAILS
- SECTION VIII FORMATION AND DEVELOPMENT OF TAILS
- SECTION IX BRILLIANCY OF COMETS
- SECTION X DIMENSIONS OF NUCLEI AND TAILS
- 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 - COMETARY NUCLEI, TAILS, AND COMÆ
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
- 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
- SECTION I COMETS PHYSICALLY CONSIDERED
- SECTION II COMETARY NUCLEI, TAILS, AND COMÆ
- SECTION III COMETS DEVOID OF NUCLEUS AND TAIL
- SECTION IV DIRECTION OF THE TAILS OF COMETS
- SECTION V NUMBER OF TAILS
- SECTION VI DIFFERENT FORMS OF TAILS
- SECTION VII LENGTH OF TAILS
- SECTION VIII FORMATION AND DEVELOPMENT OF TAILS
- SECTION IX BRILLIANCY OF COMETS
- SECTION X DIMENSIONS OF NUCLEI AND TAILS
- 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
Comæ and tails–Classification of the ancients according to apparent external form ; the twelve kinds of comets described by Pliny–The ‘ Guest-star ’ of the Chinese–Modern definitions : nucleus, nebulosity or atmosphere; tails.
What is the distinctive sign of a comet by which it is universally known, by which it is distinguished from all other celestial bodies? Everyone answers at once, it is the train of luminous vapour, the nebulosity of more or less length, which accompanies it or at least surrounds it; in other words, the tail and the coma
This is what the etymology implies, the word comet signifying long-haired or hairy. Armed with its tail, which appears brandished in the heavens like an uplifted sword or a flaming torch, the precursor of some untoward event, a comet is everywhere recognised on the instant of its appearance; it needs no passport signed by astronomers to prove its identity. But should the tail be absent, should no appendage or surrounding nebulosity distinguish the celestial visitor on its apparition, for the world at large it is no comet, but simply an ordinary star like any other.
Nevertheless, there are tailless comets. The comet of 1585 was equal to Jupiter in size, but less brilliant; its light was dull. It had neither beard nor tail, and it might have been compared to the nebula in Cancer (Pingré).
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- The World of Comets , pp. 196 - 200Publisher: Cambridge University PressPrint publication year: 2010First published in: 1877