ALSO BY BARRY PARKER
Einstein's Brainchild
Quantum Legacy
Einstein: The Passions of a Scientist
Albert Einstein's Vision
Published 2014 by Prometheus Books
The Physics of War: From Arrows to Atoms. Copyright © 2014 by Barry Parker. All rights reserved. No part of this publication may be reproduced, stored in a retrieval system, or transmitted in any form or by any means, digital, electronic, mechanical, photocopying, recording, or otherwise, or conveyed via the Internet or a website without prior written permission of the publisher, except in the case of brief quotations embodied in critical articles and reviews.
Interior artwork by Lori Scoffield Beer
Cover image © 2013 Media Bakery and BIGSTOCK
Jacket design by Grace M. Conti-Zilsberger
Inquiries should be addressed to
Prometheus Books
59 John Glenn Drive
Amherst, New York 14228–2119
VOICE: 716–691–0133
FAX: 716–691–0137
WWW.PROMETHEUSBOOKS.COM
18 17 16 15 14 5 4 3 2 1
Library of Congress Cataloging-in-Publication Data Pending
ISBN 978-1-61614-803-4 (hardcover)
ISBN 978-1-61614-804-1 (ebook)
Printed in the United States of America
PREFACE
CHAPTER 1: INTRODUCTION
Summary of the Book
CHAPTER 2: EARLY WARS AND THE BEGINNING OF PHYSICS
Battle of Kadesh
The Wonder Weapon
Copper, Bronze, and Iron
The Assyrians
Greeks and the Beginning of Physics
The New Wonder Machines
Alexander the Great
Archimedes
CHAPTER 3: BASIC PHYSICS OF EARLY WEAPONS
Velocity and Acceleration
Force and Inertia
Momentum and Impulse
The Effect of Gravity
Energy and Power
Angular Momentum and Torque
Machines
Physics of the Bow and Arrow
Physics of Other Early Weapons
CHAPTER 4: THE RISE AND FALL OF THE ROMAN EMPIRE AND THE EARLY ENGLISH-FRENCH WARS
The Romans and Their Weapons
Early English-French Wars
Origin and Physics of the Longbow
CHAPTER 5: GUNPOWDER AND CANNONS: THE DISCOVERIES THAT CHANGED THE ART OF WAR AND THE WORLD
Roger Bacon
Development of the Cannon
The Hundred Years’ War
The Basilica and the Siege of Constantinople
Cannons in the English-Scottish Wars
The French
Charles VIII and Victory over Naples
CHAPTER 6: THREE MEN AHEAD OF THEIR TIME: DA VINCI, TARTAGLIA, AND GALILEO
Leonardo and Physics
Leonardo's Military Inventions
Leonardo's Attitude toward War
Tartaglia
Galileo
CHAPTER 7: FROM EARLY GUNS TO TOTAL DESTRUCTION AND DISCOVERY
The Guns of War
The War at Sea
Henry VIII of England
William Gilbert
The Problem of Longitude
The Thirty Years’ War
Swedish Intervention
A New Era of Discovery: Isaac Newton
CHAPTER 8: THE IMPACT OF THE INDUSTRIAL REVOLUTION
Introduction
The French Revolution
The English Revolution
James Watt and the Steam Engine
John “Iron Mad” Wilkinson
Benjamin Robins
The Flintlock
Christiaan Huygens
Physics and the Industrial Revolution
CHAPTER 9: NAPOLEON'S WEAPONS AND NEW BREAKTHROUGHS IN PHYSICS
The French Revolution
Jean-Baptiste Vaquette de Gribeauval
Napoleon and His Weapons
Count Rumford
New Breakthroughs in Physics
How This Affected Warfare
CHAPTER 10: THE AMERICAN CIVIL WAR
Development of the Percussion Cap
The Minié Ball
A Revolution in Rifles and Cannons
The War
The Role of the Telegraph
The Dynamo (Generator)
The Gatling Gun
The War at Sea
Physics of the Propeller
“Damn the Torpedoes”
Submarines
Balloons
CHAPTER 11: WHERE DOES THE BULLET GO? BALLISTICS OF RIFLE BULLETS AND CANNON SHELLS
Internal Ballistics
Recoil
Transitional Ballistics and the Sonic Boom
External Ballistics
Stability of the Bullet
Terminal Ballistics
CHAPTER 12: HEY, LOOK…IT FLIES! AERODYNAMICS AND THE FIRST AIRPLANES
Discoveries That Led to the Airplane
The Wright Brothers
What Makes an Airplane Fly?
The Physical, More Exact Explanation of Lift
Details of Drag
Steering and Maneuvering the Airplane
First Use of Airplanes in War
CHAPTER 13: THE MACHINE GUN WAR—WORLD WAR I
Development of the Machine Gun
Other Weapons
How the War Started
The First Warplanes
The War at Sea and the Menace beneath the Sea
The Final Horror—Poisonous Gas
The First Tanks
America Enters the War
CHAPTER 14: THE INVISIBLE RAYS: THE DEVELOPMENT AND USE OF RADIO AND RADAR IN WAR
The Production and Detection of Electromagnetic Waves
The Electromagnetic Spectrum
Radio Waves
X-rays
Light and Infrared
Radar
An Amazing Discovery
CHAPTER 15: SONAR AND THE SUBMARINE
Archimedes’ Principle
Physics of Submarines
Power for the Propellers
Shape and Periscopes
Navigation
Sonar
Torpedoes
How Torpedoes Work
Submarines in World War II
CHAPTER 16: THE GREAT WAR: WORLD WAR II
How the War Started
Ready for War
The Battle of France, and Dunkirk
The Radar Advantage
The Battle of Britain
American Entry into the War
Advances in Aviation
The First Rockets in War
Other Weapons and Small Arms
Computers and Intelligence
CHAPTER 17: THE ATOMIC BOMB
The Beginning
Einstein's Role
The Italian Breakthrough
Hahn, Meitner, and Strassmann
Christmas 1938
A Chain Reaction
The Letter to Roosevelt
The War Begins
Meanwhile in England
Heisenberg and Bohr
The Manhattan Project
The First Reactor
The Continuing Manhattan Project
Trinity
The German Bomb
Decision to Use the Bomb on Japan
CHAPTER 18: THE HYDROGEN BOMB, INTERCONTINENTAL MISSILES, LASERS, AND THE FUTURE
Development of the Hydrogen Bomb
The Ulam-Teller Breakthrough
The First Test: Mike
Physics of the Hydrogen Bomb
Long-Range Missiles
Other Weapons: Lasers
Transistors, Microchips,
and Computers
Satellites and Drones
Futuristic Weapons of War
NOTES
SELECTED BIBLIOGRAPHY
INDEX
I mentioned to a friend that I was writing a book on the physics of war. “What does physics have to do with war?” he asked. “Oh, you mean the atomic bomb,” he added. And indeed most people know that physics had something to do with the atomic bomb. But in reality it has made many contributions other than the atomic bomb, and not all of them have led to the creation of offensive weapons that have caused damage and grief. It has also been helpful for defense, and one of the best examples of this was the invention of radar just before World War II. It allowed the British to track incoming German planes and take action to defend themselves. The invention of radar no doubt saved thousands of lives during the Battle of Britain. The discovery of x-rays by Röntgen has also played a large role in war, and there's no doubt that it has saved lives.
And it's not just modern weapons that have been based on the principles of physics. Even though they knew little physics, early civilizations, such as the Egyptians, Assyrians, Greeks and Romans, used physics in devising their weapons. Indeed, all through history physics has played an important role in the development of weapons.
As the basic principles of physics were discovered by such people as Galileo, Newton, Huygens, Einstein, and others, it became a science that was solidly based on a firm foundation. At the same time, however, it became more complex and more difficult for the layperson to understand. But it is important that people other than scientists understand, at least to some degree, what is going on in the world of science, and I'm hoping that the present book will help in this respect. I would like to also mention that although physics has been used extensively in war, it has been found to have many applications for the betterment of humankind.
In as many places as possible I've tried to use a story format to make the book more readable and interesting. I've used a few formulas; I hope they don't scare you. I've added them for anyone that is particularly interested in the details of the physics behind the weapons. You can ignore them without losing much.
Finally, I would like to thank my artist, Lori Beer, for an excellent job on the diagrams. I'm sure they will be helpful to most people.
The first well-documented battle in the history of the world took place in 1457 BCE on the Plain of Esdraelon, near the city of Megiddo in modern day Syria. It is usually referred to as the Battle of Megiddo. Megiddo, along with several other cities in the region of Palestine and Syria, had formed a coalition under the Prince of Kadesh, and had decided to break away from Egypt. Egypt's pharaoh, Thutmose III, was determined to stop the rebellion. With an army of ten thousand to fifteen thousand men, including infantry, archers, and cavalry, he marched toward Megiddo, arriving within a few miles of it in April. As the army camped at a place called Yaham, Thutmose conferred with his generals. There were three routes from Yaham to Megiddo; two were relatively easy, but a third, more direct route through the mountains, was quite difficult. Part of the route passed through a very narrow pass where his soldiers would have to travel single file. In addition, the cavalry would have to dismount and lead their horses. Strung out in this way, they would be vulnerable if the Prince of Kadesh decided to attack. Thutmose's generals encouraged him to take one of the easy routes. As he thought about it, however, he realized that the Prince of Kadesh and his troops would not expect them to come through the mountains because of its difficult terrain. They would likely be waiting at some point along the other two routes. So, to the disappointment of his generals, he decided to take the route through the mountains.1
And indeed, Thutmose was right. The Prince of Kadesh's men were waiting for them at the ends of the two easy routes. The prince had split his army into two groups, with one half of it in the south and the other half in the north. Furthermore, he had left almost no men to guard the city of Megiddo.
The following day Thutmose led his men through the treacherous pass, and when they broke out into the open, with the city of Megiddo directly ahead, they saw that it was lightly guarded. But Thutmose didn't want to attack the city at this point. He still had to defeat the prince's army. It was late in the evening, so he camped overnight and was ready for battle the next morning. He split his men into three wings and moved quickly to attack the flanks of both sections of the prince's army. They were so surprised by an attack coming from an unexpected direction that most of the men broke rank and fled. Most of them ran for the shelter of the city.2
Thutmose pursued them, and by the time he got to the city he could see that many of them were trapped. The defenders of the city had seen the fleeing men coming and had opened the gate, but as Thutmose's army came into view they immediately shut it, leaving many outside. The citizens inside, however, acted quickly; they lowered ropes made of clothes to pull the stranded soldiers over the walls.
Thutmose wanted to attack the city, but by now most of his soldiers were plundering the enemy camp, taking whatever they could find. By the time he got his army reorganized most of the enemy, including the Prince of Kadesh, were safe in the city, which had a high, strong wall all around it. Thutmose could see that it would be suicidal to attack it directly, so he decided on a siege. His troops had plenty of supplies, and there were more supplies available in the surrounding area. But the people within the city were cut off, so it was only a matter of time before they ran out of food and other supplies. The siege lasted for seven months, but finally the citizens and what was left of the army surrendered. By this time, however, the Prince of Kadesh had somehow escaped.
It had taken longer than he had hoped. Nevertheless, Thutmose had soundly defeated the prince's army, and he had captured Megiddo.
SUMMARY OF THE BOOK
Like all rulers or generals going to war, Thutmose III was looking for something that would give him an advantage, and he found it. In his case it was a tactic that gave him an element of surprise. Throughout history, and even today, military leaders contemplating war, or involved in it, are still looking for some sort of advantage over their enemy. Whereas Thutmose used a surprise tactic to his advantage, throughout most of history military leaders have searched for a new “wonder weapon”; in essence, a weapon the enemy does not have. As we'll see in this book, it is usually physics that provides a path to this new weapon. Physics and science in general has indeed been of tremendous value to military leaders. It has given them a better understanding of ballistics so that they can aim their guns better; it has given them radar so that they can detect the enemy before they are detected; it has given them an understanding of the electromagnetic spectrum so they can use radiation in various military applications; it has given them an understanding of rocketry and jet engines, and an understanding of the secrets deep within the atom so they are able to build super bombs.
This book gives an overview of most branches of physics, and it shows how they are used for military applications. It also gives a summary of the history of war all the way from the first bows and arrows and chariots through to the atomic and hydrogen bombs. We begin in chapter 2 with the Egyptians, Assyrians, and early Greeks. We'll look at some of their interesting weapons, such as the ballista, the onager, and the trebuchet, all of which involve basic principles of physics.
In chapter 4 we look at the rise and fall of the greatest military establishment ever seen up to that time, namely the Roman Empire. The early English-French battles are also included in this chapter; one of the most famous of these was the Battle of Agincourt, where the English used the longbow to overcome a much larger and more powerful army. It was their secret new weapon.
In chapter 5 we see the introduction of new technologies that completely changed the nature of war: gunpowder and cannons. Cannons were, in fact, so effective that they led to wars that lasted for a hundred years. At this stage, however, we can't say that physics made large contributions to the art of war because, for the most part, it didn't exist. But as we'll
see in chapter 6, three men, including Galileo, made important advances and helped put physics on a much better footing.
With these advances and others, war became even more prevalent throughout Europe. Rifles improved significantly, beginning with the matchlock and ending with the flintlock a few years later. In addition, ships were now getting larger, and they were soon equipped with cannons. Furthermore, with William Gilbert's discoveries in relation to magnetism came a better understanding of navigation at sea, so sailors could now head out into the unknown without worrying about getting lost.
Then came the magnificent discoveries of Isaac Newton, and physics was raised to new heights of understanding. His discoveries are discussed in chapter 7. Following this came the Industrial Revolution, discussed in chapter 8. In a period of less than one hundred years the civilized world changed significantly. In particular, several new techniques, including mass production, made war even more devastating.
In chapter 9 we look at Napoleon and his weapons and tactics. Without doubt, he is one of history's greatest military tacticians, but strangely he didn't introduce many innovative new weapons. About this time another revolution in physics was occurring, and it would lead to a tremendous change in warfare. It began with the discovery that a “current” of electricity could be produced by a simple device called a pile. Soon the new phenomenon was all the rage throughout Europe, and it quickly attracted some of the best minds in physics: Oersted, Ohm, Ampere, and Faraday. Electric generators, motors, and other electrical devices followed, and of course, they eventually became central to war.
In chapter 10 we come to the American Civil War, which was the most devastating war ever fought on American soil. By this time tremendous advances had occurred, including the percussion cap, which quickly led to much more accurate and deadly rifles, along with the first use of submarines, balloons, and the telegraph in warfare.
In chapter 12 we discuss the airplane. World War I erupted only a decade after the first flight of the Wright brothers. And it didn't take long before airplanes were used in the war. “Dogfights” were soon common, and the airplane has played a central role in warfare ever since. Many other new weapons were also developed in World War I. They included huge new cannons, the first tanks, poisonous gas, and flamethrowers.