Top 10 Game-changing Military Technologies

­Before the advent of the chariot, men fought wars on foot. Soldiers packed into block formation and fought each other with stabbing and slashing weapons. Think of the chariot as an ancient tank. It revolutionized war by becoming the first moving vehicle on the battlefield.

The first chariots, appearing around 3000 B.C. in Mesopotamia, were dreadfully slow and so heavy that only oxen could pull them [source: Cotterell]. Being impractical for battle, kings rode the solid wooden carts to the battlefield, then got out and fought.

But around 1800 B.C., chariots changed, shedding weight and adding spoked wheels [source: Cotterell]. The best of these were so light that a charioteer, or driver, could lift it over his head. An archer and driver rode together on the back of the chariot, which was drawn by horses. The chariot became a fast war machine.

These advanced chariots meant trouble for foot soldiers. Charioteers blazed past infantries, riddling soldiers with arrows or running right over them.

"Chariots were the superweapons of their age," says military historian Dr. Alex Roland. "They trumped everything else and became the decider of warfare." Chariots spread from West Asia and Egypt to India, China and Europe. States that had the money built thousands of chariots, which dominated warfare in the Middle East between 1800 and 1200 B.C. [source: Roland].

Not only did chariots change the military game, they became a game for the Greeks and the Romans, and of course, Ben Hur.

­What military technology did the Chinese use as a slightly toxic remedy for ringworm? Find out next.

­Gunpowder exploded into history around 800 A.D. The Chinese accidentally invented it while trying to mix immortality elixirs. Over 400 years, the Chinese made early versions of every gunpowder weapon to exist, including bombs, guns and a type of cannon called "the flying-cloud thunderclap eruptor" [source: Ponting]. The Chinese government tried to keep gunpowder a secret, but it leaked to groups that attacked China and eventually the knowledge traveled across trade routes.

Once prevalent, gunpowder allowed civilized peoples in Europe and Asia to dominate over barbarians. It also ended the longest empire in history. Thanks to its capital city of Constantinople, the Byzantine empire was unstoppable. Constantinople's three layers of walls made it the most fortified city in history. No siege equipment in the world -- no ladders or battering rams -- could break in. But the Ottoman Turks, led by Mehmed II, wheeled 26-foot (8-meter) cannons to the walls, and using gunpowder, shot massive balls that demolished them. With that, the Byzantine empire and medieval warfare ended, since no castle or lance-bearing knight could withstand the force of gunpowder weapons.

In essence, armies acquired gunpowder before they acquired good aim. See what we mean next.

You may know the saying, "Don't shoot until you see the whites of their eyes." Soldiers during the American Revolutionary War certainly knew what it meant. Guns of the time had smooth barrels, which sent bullets flying in all directions. You couldn't hit the enemy unless you were close. Back then, soldiers stood almost face to face and shot each other.

But rifled guns, used widely starting in the 1800s, had grooved barrels. These guns spun the bullets, so that they traveled straight for hundreds of yards, vastly improving long-range accuracy [source: Boot]. Standing up during combat became very dangerous. For example, during the Battle of Gettysburg in the American Civil War, Confederate Maj. Gen. George Pickett followed orders to march his soldiers upright across an open field. As soon as Pickett's soldiers were in range, Union soldiers popped up from behind a wall and picked them off from a distance. During World War I, the nightmare worsened as machine guns mowed down soldiers advancing between trenches [source: Roland]. Soldiers eventually learned to hug the ground.

Rifled barrels changed naval warfare, too. Ship guns now had such range and accuracy that ships could fire at each other without seeing one another.

­Those little grooves "expanded the size and the lethality of the battlefield," says historian Roland.

­Since it's hard to imagine how this ubiquitous, behind-the-scenes technology made a difference, imagine war without it. On land, we would have no tanks or supply trucks. In the air, we would have no airplanes, ballistic missiles, jets or helicopters. At sea, we would have no submarines. All of these vehicles require the power generated from burning fuel.

The internal combustion engine altered the speed and range of war, starting in World War I and continuing today. During World War I, machine gunners on the front lines had to wait for horse-drawn wagons to bring their ammunition from railheads, until supply trucks made the link [source: van Creveld] . In World War II, the Germans famously drove tanks up to 60 miles (97 kilometers) a day to gain territory from the edge of Poland to Moscow in six months [source: van Creveld]. One of the first ballistic missiles, the German V-2, sped up war even more since it could destroy a target 200 miles (322 kilometers) away in five minutes [source: Parson].

Without the internal combustion engine, steam engines could still power war. But these engines are only efficient enough to move ships or locomotives. War tactics would be stuck in the late 1800s if we still relied on steam.

In fact, the ubiquitous internal combustion engine powers our next technology.

­Airplanes brought war into the skies.

Italy was the first to use airplanes for military purposes. While fighting Turkey for control of ibya in 1911, Italians sent airplanes to find, photograph and bomb Turkish targets [source: Kinney]. By World War I, Germany, Austria, Hungary, France and Britain had air forces hundreds of planes strong. First, countries just sent planes to spy on their enemies. Next they launched fighter planes to shoot down the spy planes. Finally, bomber planes were used to hit cities and troops.

Airplanes changed war by offering an alternative to land or sea invasion, so that fewer soldiers would occupy the battlefield and be at risk. But airplanes also endangered civilians, says historian Roland.

During World War II, both the military convenience and danger of air attacks became clear. To force Japan to surrender while avoiding a land invasion, the United States struck the main island by air. The first bombs hit industrial targets and did little damage. The United States then firebombed Tokyo, killing 80,000 residents and leaving 1 million homeless [source: Britannica]. Airplanes then dropped atomic bombs that killed more than 100,000 civilians and injured many thousands more.

"The early theorists of airpower thought that if civilian populations were subjected to bombing attacks, they would sue for peace. It turns out that didn't happen. The result is that airpower spread warfare to the civilian population without being decisive. It's not a happy story," says Roland.

Our next technology carries messages, not bombs, through the air.

­Don't get us wrong. Before radio, commanders could control big armies. They used runners, riders, flags and even pigeons to communicate, but just ask Napoleon how hard it was. In the battle of Jena against Prussia, he tried to manage more than 100,000 soldiers -- about the limit in his time -- and he forgot about some troops [source: Britannica].

"As armies grew larger, the need for communication to maneuver them in the field became more important," says Roland. "Radio meant that a commander could be in instant contact with all of his subcommanders and organizations."

Navies used wireless telegraphs, the first military radios, during World War I [source: Britannica]. These machines beamed messages from land stations to sea, without the need for wire, but enemies readily intercepted the messages and cracked the codes.

By World War II, short-wave radios in airplanes, tanks, and ships helped these forces communicate over some 150 miles (241 kilometers). [source: Roland]. The Germans used the communications link with great success in their "blitzkrieg" technique. In this technique, tanks and airplanes performed a battlefield ballet; as airplanes provided cover, tanks broke through enemy lines. To coordinate the movement, pilots and soldiers talked by radio. Using blitzkrieg, the Germans blazed through the Netherlands, Belgium and much of France in 10 days [source: Parker].

For more on waging war with waves sent across the sky, read about our next technology.

­Radar changed both offense and defense in war. It was the first automated way to see the enemy, but also to be seen. As late as World War I, watching for the enemy meant stationing a man in the field with field glasses and telling him to phone the commander when he saw a plane. Forget that on a cloudy day.

In 1935, a scientific paper explained radar, a method for spotting the enemy by bouncing radio waves or microwaves off solid objects. By 1939, Britain had built the first radar system. It planted 350-foot (107-meter) radar towers around the island to watch the skies [source: Boot]. During the Battle of Britain in 1940, the towers saved Britain. As German planes swooped in to bomb the island, the towers relayed warnings to the British air command, which speedily sent planes to shoot down the attackers.

Radar also changed war at sea. During World War II, German submarines torpedoed British and American ships as they crossed the Atlantic. But airplanes, once outfitted with microwave radar, trumped the subs. The Allies sent airplanes to detect the subs when they surfaced and drop underwater bombs.

Because radar enhanced commanders' ability to see, everyone had to work harder to stay out of sight. The British began shooting metal strips, called chaff, out of its planes to obscure radar's view [source: Boot].

Neither radar nor anything else packs the wallop of our next military technology.

­For centuries, military theorists talked about fi­nding a weapon so horrible, no one would use it. "Most weapons people thought would be in that category just made war more horrible," says historian Roland. "Nuclear weapons are the first that everybody agrees we can't use."

Nuclear weapons were used on people just twice. In 1945, the United States dropped two atomic bombs on Japan at the end of World War II. The "Little Boy" bomb carried fissionable uranium, and the reaction of just a fraction of it sent a shock wave, fireball and radiation across Hiroshima, killing 90,000 people. The "Fat Man" bomb carried fissionable plutonium, and its explosion immediately killed 35,000 people in Nagasaki.

Even as world powers built stockpiles of nuclear weapons and executed numerous tests, knowledge of the devastation in Japan has deterred their use.

"We haven't had any great power war since 1945, and it's because of nuclear weapons," says Roland. "They have made for a much more peaceful world."

Peaceful, of course, is a relative term. Numerous wars have torn apart countries since 1945, but none so far on the scale of either of the first two world wars.

If you prefer eavesdropping to bomb-dropping, read on.

­What should a nation do when its adversary has a nuclear weapon pointed its way? Spy, of course.

During the Cold War, the Soviet Union and United States found themselves in exactly this situation. Both sides had nuclear missiles able to reach and flatten any city across the world in half an hour. Both sides also had sent nuclear missiles on submarines.

The United States began the Discoverer spy satellite program to watch how fast the Soviet Union was making missiles and where they were being sent. Discoverer 4, the first U.S. camera-carrying satellite, launched in 1959 but didn't reach orbit, but Discoverer 14 went up in 1960 and returned photos [sources: NASA: Discover 4, NASA: Discoverer 14].

In all, the "very suspicious" United States used satellites to track Soviet missile preparations and make sure the Soviets weren't going to invade Europe, says Roland. The Soviet Union also had satellites trained on the United States.

"Reconnaissance satellites allowed both sides to look at the strategic assets of the other side and convince themselves that a sneak attack wasn't being prepared," says Roland. "These satellites gave everyone confidence that they knew what the enemy was doing. That kept tensions to a minimum. The satellites may well have prevented World War III."

­Modern spy satellites can do more than take photos. They can collect telephone, ­radio and Internet signals, adding to the ways commanders can guess about what's happening on the ground [source: Britannica]. For more military uses of satellites, continue to our final game-changing military technology.

­GPS turned the world into a giant, instantly accessible map.

The U.S. Department of Defense built the U.S. version of GPS, Navstar GPS, between 1989 and 1994 [source: Britannica]. It launched 24 main satellites that constantly emit radio waves. Anyone with a receiver that can pick up a few satellites' waves can triangulate his or her position.

GPS became an excellent tool for navigation. A soldier with a receiver could now navigate in the pitch dark or in any foreign place without a map.

The navigation tool also proved helpful for planning strikes. If a soldier who is carrying a GPS receiver meets enemy troops, he or she can record the enemy's position -- down to the longitude, latitude and altitude. By sending those GPS coordinates to fellow soldiers, the individual can alert the commander, the attack plane and 500 other soldiers as to the enemy's location. Being able to immediately blow the enemy's cover changed war.

The Gulf War illustrated the change, says Roland. "Americans feared the Iraqis would have an advantage because they'd be fighting in the desert in their own country. But it turns out the Americans had the advantage because they had GPS receivers. They could navigate at night and in dust storms. They always knew exactly where they were and where the Iraqis were."

GPS has also made air strikes more accurate. Satellites are used to map the targets and guide the bombs and missiles. These strikes minimize collateral damage and civilian casualties. As time goes on, we are discovering more applications and depending more on GPS.

Ultimately, though, the outcome of war depends on more than just advanced technology, but it certainly doesn't hurt your chances on the battlefield.

That ends our tour of military technologies that changed the game, for better or worse.