Science News has been covering nuclear physics since our earliest incarnation, starting with scientists’ effort to decode the secrets of the atom. In the 1930s, readers learned about the discovery of the positron and scientists’ first splitting of a uranium atom. The first sustained nuclear reaction followed soon after, in a repurposed squash court at the University of Chicago in 1942.
By then, what had once been a pursuit of basic knowledge had become a desperate wartime race to develop a nuclear weapon. The United States won that race. In 1945, U.S. forces dropped two atomic bombs on Japan that destroyed the cities of Hiroshima and Nagasaki, hastening the end of World War II.
In the 80 years since, no other nuclear bomb has been used as a weapon, though thousands of devices have been developed for testing. And while tests by the United States and other countries continued after the war, most countries halted these tests in the 1990s, around the time of the Comprehensive Nuclear-Test-Ban Treaty.
I confess that over the last 30 years, I have not spent much time ruminating on the threat of nuclear Armageddon. That changed for me in 2022, when Russia invaded Ukraine. Russian President Vladimir Putin lowered the threshold for a nuclear strike and reminded the world of the power of nuclear weapons to intimidate adversaries.
Fortunately, senior physics writer Emily Conover has been keeping watch on the science of nuclear weaponry and the geopolitical forces that affect it. A particle physicist turned journalist, Conover has a deep understanding of how the weapons work. In this issue, she explains the science of weapons testing. Today, nuclear bombs are no longer being blown up in the Nevada desert. Instead, scientists are using “subcritical” nuclear experiments and computer simulations to gauge whether the weapons in the U.S. stockpile are still functional.
Conover also explains the renewed interest in the United States and elsewhere in reviving explosive tests. Physicists are divided on whether detonations are helpful to know if the bombs will work, Conover told me: “We have extremely good computer models of these weapons, but there could always be something we’ve missed.”
It’s unsettling to know that nuclear weapons testing may be back soon. But if even very limited knowledge is power, I’m glad to know the state of the science in a world that feels more unstable by the day.