Atomic bomb

Atomic bombs were the weapons which held the key to war begun when the Race invaded Earth. At the outset of the conflict, only the Race possessed them, and first detonated several high in the Earth's atmosphere in an effort to disrupt Tosevites' radio signals. Atvar also used them to destroy the cities of Berlin and Washington, DC early in the war.

Unbeknownst to the Conquest Fleet when it arrived, humans had already discovered the divisibility of the atom and the tremendous energy yield it could produce. Most of the major combatants in the interrupted World War II had begun programs to build such weapons.

The Soviet Union struck first when they built a bomb using uranium captured in the destruction of one of the Race's starships. They buried this bomb under a stretch of line they controlled, then withdrew. When the Race took possession of this area, they detonated the bomb via radio. Since the Race enjoyed air supremacy, this became the humans' preferred tactic for delivering the bomb. It was used by both the United States and Germany when each of those countries developed bombs entirely of their own manufacture.

By the end of the war, the US, the USSR, and Germany had all learned to build atomic bombs on their own. Though reluctant to risk rendering the planet uninhabitable, Atvar retaliated to each human bomb by destroying a city in any nation that used such a weapon, each time it did so. He also destroyed Tokyo, thus precluding the Japanese from building a bomb before the end of the war (though they did succeed in building one many years later, after the arrival of the Colonization Fleet.) The Race also launched unprovoked atomic attacks on two cities in Australia.

These tactics did not deter the atomic-capable human governments, which were engaged in a war for survival. Eventually Atvar was forced to negotiate with these governments, creating the uneasy truce which would exist on Earth for decades to come.

In the next twenty years, human atomic weapons improved. Most importantly, they were coupled with rocket technology to create nuclear missiles, allowing the human powers to use these weapons against the Race's orbital starships. These weapons were used many times both on land and in space in the 1960s: by the United States in Earl Warren's attack on the Colonization Fleet; by the Race in its retaliatory attack on Indianapolis; and by both sides in the Race's 1960s war with Germany. They were even carried aboard the Admiral Peary when it journeyed to the Tau Ceti system.