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
- 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
- SECTION I WHAT IS A COMET?
- SECTION II CARDAN'S HYPOTHESIS
- SECTION III THEORY OF THE IMPULSION OF THE SOLAR BAYS
- SECTION IV HYPOTHESIS OF AN APPARENT REPULSION
- SECTION V THEORY OF OLBERS AND BESSEL
- SECTION VI THEORY OF COMETARY PHENOMENA
- SECTION VII THE REPULSIVE FORCE A REAL PHYSICAL FORCE
- SECTION VIII THEORY OF THE ACTINIC ACTION OF THE SOLAR RAYS
- SECTION IX COMETS AND THE RESISTANCE OF THE ETHER
- 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 IX - COMETS AND THE RESISTANCE OF THE ETHER
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
- 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
- SECTION I WHAT IS A COMET?
- SECTION II CARDAN'S HYPOTHESIS
- SECTION III THEORY OF THE IMPULSION OF THE SOLAR BAYS
- SECTION IV HYPOTHESIS OF AN APPARENT REPULSION
- SECTION V THEORY OF OLBERS AND BESSEL
- SECTION VI THEORY OF COMETARY PHENOMENA
- SECTION VII THE REPULSIVE FORCE A REAL PHYSICAL FORCE
- SECTION VIII THEORY OF THE ACTINIC ACTION OF THE SOLAR RAYS
- SECTION IX COMETS AND THE RESISTANCE OF THE ETHER
- 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
Accelerated motion of Encke's comet; its periods continually diminish–It describes a spiral, and will ultimately fall into the sun–Hypothesis of a resisting medium; how does the resistance of a medium increase the rapidity of motion?–The nature of this supposed medium, according to Arago, Encke, and Plana–Objections of M. Faye; the acceleration of motion explained by the tangential component of the repulsive force.
In our account of the periodic comet of Encke we gave, together with the dates of its successive apparitions, the durations of the revolutions comprised between these dates. If the reader will turn back to the table on p. III he will readily perceive that these durations are unequal, and that the period is continually decreasing, and has suffered a diminution of a little more than two days, or exactly of 2.06 days. As the table includes twenty-two revolutions of the comet it is at most a diminution in each revolution of two hours twenty-two minutes, a quantity small in itself, but which, incessantly accumulating, is capable of producing changes of very great importance in the course of time.
The discovery of this acceleration is due to the astronomer whose name the comet bears.
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- The World of Comets , pp. 406 - 414Publisher: Cambridge University PressPrint publication year: 2010First published in: 1877