Three powers agree: no more bombs in the sky, underwater, or in space
By 1963, strontium-90 was showing up in children's teeth and mothers' milk, and scientists like Linus Pauling had gathered more than 9,000 signatures warning of fallout from atmospheric testing. In Moscow on August 5, negotiators for the United States, the United Kingdom, and the Soviet Union signed the Partial Nuclear Test Ban Treaty, banning nuclear explosions above ground, underwater, and in outer space. Underground testing stayed legal. The treaty, the first major arms-control deal of the Cold War, took effect that October.
Kennedy signed the treaty about eight weeks after his American University speech calling for a thaw with Moscow, and about six weeks after installing the Washington-Moscow hotline. It marked the first time American nuclear policy bent toward negotiated limits rather than unrestrained buildup.
QHow many countries eventually joined a treaty signed by just three nations?
The Partial Test Ban Treaty started as a three-way deal between Washington, London, and Moscow, but it grew into one of the most joined agreements of the era, with 123 other states eventually signing on. Eventually 123 other states signed on as parties, while ten more signed but never ratified it. France and China refused entirely, and kept testing in the open air for years, France until 1974 and China until 1980.
QWhat tipped off scientists that fallout was reaching American children?
Researchers ran what became known as the Baby Tooth Survey, collecting baby teeth from thousands of American children and testing them for strontium-90, a radioactive isotope that behaves like calcium in the body and lodges in bone and teeth. The survey confirmed that fallout from atmospheric testing was showing up inside American kids, not just drifting harmlessly over test sites in Nevada and the Pacific. That data became a central piece of evidence in the public campaign against atmospheric testing.
QDid a mysterious 1979 flash of light ever get pinned on anyone?
In September 1979, a US satellite detected a double flash over the South Atlantic consistent with a nuclear detonation, an event now called the Vela incident. Suspicion fell on Israel and South Africa, both signatories to the test ban treaty, but neither country has ever confirmed responsibility and no formal accusation was ever proven. No one has ever been formally blamed for it.
