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
- SECTION I COMETS WHOSE RETURN HAS BEEN OBSERVED
- SECTION II HALLEY'S COMET
- SECTION III ENCKE'S COMET; OR, THE SHORT PERIOD COMET
- SECTION IV BIELA'S OR GAMBART'S COMET
- SECTION V FAYE'S COMET
- SECTION VI BRORSEN'S COMET
- SECTION VII D'ARREST'S COMET
- SECTION VIII TUTTLE'S COMET
- SECTION IX WINNECKE'S PERIODICAL COMET
- SECTION X TEMPEL'S SHORT PERIOD COMET
- 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 I - COMETS WHOSE RETURN HAS BEEN OBSERVED
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
- SECTION I COMETS WHOSE RETURN HAS BEEN OBSERVED
- SECTION II HALLEY'S COMET
- SECTION III ENCKE'S COMET; OR, THE SHORT PERIOD COMET
- SECTION IV BIELA'S OR GAMBART'S COMET
- SECTION V FAYE'S COMET
- SECTION VI BRORSEN'S COMET
- SECTION VII D'ARREST'S COMET
- SECTION VIII TUTTLE'S COMET
- SECTION IX WINNECKE'S PERIODICAL COMET
- SECTION X TEMPEL'S SHORT PERIOD COMET
- 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
How to discover the periodicity of an observed Comet and predict its return –First method: comparison of the elements of the orbit with those of comets that have been catalogued –Resemblance or identity of these elements; presumed period deduced from it–Second method: direct calculation of elliptic elements – Third method.
There are, however, a certain number of comets of whose return astronomers are certain, and the time of whose apparition they can calculate. The prediction of the probable epoch at which these comets will be situated in regions of the heavens where they will be visible from the earth, and the determination of their perihelion passage, can be effected more or less accurately. These are the comets whose orbits, when calculated from a sufficient number of observations, prove to be neither parabolas nor hyperbolas, but, on the contrary, are closed and elliptic, and such that the comet thenceforth continues to describe them in regular periods; in a word, they are periodical comets Newton treated the orbits of comets as parabolic, merely in order to so represent the arc, always very short, described in the neighbourhood of the perihelion, when the comparatively small distance of the comet from the sun renders observations possible. In his opinion comets were bodies of regular periods, and which described ellipses, certainly very elongated, but in all respects similar to the planetary orbits.
- Type
- Chapter
- Information
- The World of Comets , pp. 95 - 99Publisher: Cambridge University PressPrint publication year: 2010First published in: 1877