Chapter I: Front Matter

Transcriber’s Notes:

Underscores “_” before and after a word or phrase indicate _italics_
in the original text.
Equal signs “=” before and after a word or phrase indicate =bold=
in the original text.
Small capitals have been converted to SOLID capitals.
Illustrations and footnotes have been moved so they do not break up
paragraphs.
Deprecated spellings have been preserved.
Typographical and punctuation errors have been silently corrected.

THE UNIVERSE AROUND US

Cambridge University Press
Fetter Lane, London

_Bombay_, _Calcutta_, _Madras_
_Toronto_
Macmillan

_Tokyo_
Maruzen Company, Ltd

Copyrighted in the United States of
America by the Macmillan Company

All rights reserved

The Discovery of Pluto

The two photographs were taken at the Lowell Observatory on the nights of March 2 and 5, 1930. The object indicated by arrows was seen to have moved considerably in the interval, and this proved that it was of planetary character.

The bright object in the bottom left-hand corner is the star δ Geminorum (see p. 260).]

THE
UNIVERSE
AROUND US

_By_
SIR JAMES JEANS

M.A., D.Sc., Sc.D.
LL.D., F.R.S.

CAMBRIDGE
AT THE UNIVERSITY PRESS
1930

_First Edition, September 1929_
_Reprinted November 1929_
” _January 1930_
_Second Edition, October 1930_

PRINTED IN GREAT BRITAIN

PREFACE

The present book contains a brief account, written in simple language, of the methods and results of modern astronomical research, both observational and theoretical. Special attention has been given to problems of cosmogony and evolution, and to the general structure of the universe. My ideal, perhaps never wholly attainable, has been that of making the entire book intelligible to readers with no special scientific knowledge.

Parts of the book cover the same ground as various lectures I have recently delivered to University and other audiences, including a course of wireless talks I gave last autumn. It has been found necessary to re-write these almost in their entirety, so that very few sentences remain in their original form, but those who have asked me to publish my lectures and wireless talks will find the substance of them in the present book.

J. H. JEANS
DORKING
_1 May 1929_