Bruce Bassett - Introducing Relativity: A Graphic Guide

Published by Icon Books Ltd., Omnibus Business Centre, 3941 North Road, London N7 9DP
email:
www.introducingbooks.com

ISBN: 978-184831-770-3

Text copyright 2002 Bruce Bassett
Illustrations copyright 2012 Icon Books Ltd

The author and artist have asserted their moral rights.

Originating editor: Richard Appignanesi

No part of this book may be reproduced in any form, or by any means, without prior permission in writing from the publisher.

Introductory Level Books

These books are at an introductory level and should be accessible to a wide audience.

Einstein

Introducing Einstein, Schwartz and McGuinness (Icon Books, 1999).

General Relativity

The Meaning of Relativity, Albert Einstein (Princeton University Press, 1992)

Flat and Curved Spacetimes, George Ellis and Ruth Williams (Oxford University Press, 2000).

Cosmology

There is a huge choice of popular books in the general area of cosmology. Some recommended titles include:

Cosmology: A Very Short Introduction, Peter Coles (Oxford Paperbacks, 2001).

Just Six Numbers, Martin Rees (Orion fiction, 2001).

The Big Bang, Joseph Silk (W.H. Freeman & Company, 2001).

Between Inner Space and Outer Space, John Barrow (Oxford Paperbacks, 2000).

Inflation

The Inflationary Universe, Alan Guth (Vintage, 1998).

Quantum Mechanics

Introducing Quantum Theory, McEvoy and Zarate (Icon Books).

In Search of Schrdingers Cat, John Gribbin (Corgi, 1985).

Quantum Gravity

Dreams of a Final Theory, Steven Weinberg (Vintage, 1993).

A Brief History of Time, Stephen Hawking (Bantam, 1995).

Introducing Hawking, McEvoy and Zarate (Icon Books, 1999).

Advanced Level

These require either more mathematical or physics background:

Subtle is the Lord, Abraham Pais (Oxford Paperbacks, 1984) a famous and very insightful history of Einsteins life, giving wonderful insights into the development of relativity.

Introducing Einsteins Relativity, Ray dlnverno (Clarendon Press, 1992). This is a good introduction to the mathematics and physics of GR. A standard advanced undergraduate/post-graduate text.

The classic advanced texts in GR are (notice how the first three all appeared in 1973):

The Large Scale Structure of Spacetime, Stephen Hawking and George Ellis (CUP, 1973).

Gravitation, Misner, Thorne and Wheeler (W.H. Freeman, 1973).

Gravitation and Cosmology, Steven Weinberg (John Wiley & Sons, 1972).

General Relativity, Robert Wald (Chicago University Press, 1984).

The German philosopher Immanuel Kant (17241804) delved into the critical limits of knowledge in his revolutionary text, The Critique of Pure Reason (1781). He expounded the view that space and time do not exist independently of our consciousness.

IT IS THE PRIOR CONDITION OF OUR MINDS THAT ALLOWS US TO PERCEIVE SPACE AND TIME
THIS SUGGESTS THAT SPACE & TIME MAY NOT BE ABSOLUTE ENTITIES AS NEWTON CONCEIVED THEM, AND SO KANT IS CLOSER TO EINSTEIN, AS WE SHALL SEE

Nevertheless, until Einstein, the dominant philosophy of physicists was inherited from Sir Isaac Newton (16431727).

Newtons Classical Laws of Physics

Newton was arguably the greatest of physicists and mathematicians. He contributed significantly to optics, formulated his three laws of motion, and developed differential and integral calculus independently of G.W. Leibniz (16461716). But, in terms of understanding Einsteins relativity, Newtons law of universal gravitation is the most crucial for us.

BEFORE NEWTON THE MOTION OF THE PLANETS IN THE HEAVENS WAS CONSIDERED A MYSTERIOUS ISSUE DISLOCATED FROM THE EVERYDAY WORLD
I HAD ALREADY DISCOVERED LAWS FOR THE MOTION OF THE PLANETS...
YES, BUT WHAT YOU DISCOVERED WERE EMPIRICAL LAWS WITHOUT THEORETICAL EXPLANATION

A famous but untrue story has Newton sitting under an apple tree when his great discovery of gravity literally hit him on the head.

THIS EUREKA STORY NICELY CONVEYS THE ASTONISHING INTELLECTUAL LEAP THAT NEWTON MADE...
THE APPLE FALLING TO EARTH FEELS A FORCE!

The specific importance of Newtons law of universal gravitation is that it explains and unites several phenomena within a single theory. This quest for a single unifying theory would become the driving force of 20th- and 21st-century physics.

The Law of Gravity

Newtons law of universal gravitation states that the force of gravity (F) between two objects of masses m and M is given by

where r is the distance between the two objects and G is Newtons constant. G is very small since gravity is very weak.

There are at least two implications to this law of gravity

THE FIRST IS A MATHEMATICAL DEDUCTION OF KEPLERS LAWS OF PLANETARY MOTION - GRAVITY SUPPLIES THE MISSING THEORETICAL EXPLANATION
SECOND, MY LAW GIVES THE RIGOROUS RESULT THAT PLANETS TRAVEL ON ELLIPSES RATHER THAN ON CIRCLES

Newton took several things for granted in his theory. While the earth was no longer the centre of the universe and had not been so in the eyes of many scientists since Nicolaus Copernicus (14731543) it was assumed that space and time were fundamentally different things and that both were absolute, set in marble.

HENCE, FOR NEWTON-AND FOR THOSE WHO FOLLOWED HIM-SPACE AND TIME WERE THE ABSOLUTE AND IMMUTABLE STAGES ON WHICH MATTER IN THE UNIVERSE PLAYED OUT ITS GAMES

The idea of unifying the two, apparently different, concepts of space and time fell to Einstein, as well later discuss.

Maxwells Theory of Electromagnetism

Theoretical physics had made significant progress before Einstein. In particular, James Clerk Maxwell (183179) had unified magnetism with electricity to give electromagnetism.