A stupendous plume of fire and ash rose over Hiroshima, Japan, on August 6, 1945, and again three days later over its southern neighbor Nagasaki. In the days that followed, the world’s perceptions of war changed. Rational thought seemed to demand that war had to cease, simply because it had become too terrible.

Volumes have been written over the centuries about the causes of war. Some philosophers suspect that humans have built-in physical or psychological quirks that lead to organized violence on a large scale. Others see war as an outgrowth of relationships among individuals, societies, and governments. But for many ordinary people, the use of an atomic bomb by the United States to end World War II rendered all academic discussion irrelevant.

Nevertheless, when the 21st century dawned, humans were still maiming and killing each other with undiminished vigor and in a variety of styles. People tend to fight with whatever weapons they have at hand: stones, machetes, automatic rifles—and now satellites. In 1991, during the Persian Gulf war, U.S. forces used satellites extensively, and not only to gather intelligence. Satellite-based global positioning system (GPS) navigational equipment was crucial in their race across the trackless desert to surprise the army of Iraq’s Saddam Hussein.

Analysts have theorized that the existence of atomic weapons makes world war less likely, and increases the probability of smaller, more localized conflicts and terrorism. But the result is always the same. People suffer and die.