On July 16, 1945, just before dawn, the age of nuclear terror began. A fireball brighter than the sun lit up the New Mexico desert. The watching scientists cheered and shook hands. This was the world’s first test of a nuclear weapon, and, contrary to fears that it could ignite an unstoppable chain reaction setting the whole world on fire, it had worked.
And yet, exactly what that meant was sinking in too. The lead scientist of America’s secretive Manhattan Project to build the bomb, Robert Oppenheimer, said that words of Hindu scripture ran through his mind as he watched the mushroom cloud over the explosion: “Now I am become Death, the destroyer of worlds.”
Less than a month later, the United States dropped two nuclear bombs on the Japanese cities of Hiroshima and Nagasaki to force the country’s surrender and end World War II, killing hundreds of thousands of people. It remains the only use of nuclear weapons in war.
Soviet espionage soon unlocked the secrets of that bomb, beginning a nuclear arms race that would spiral into the Cold War. But mutually assured destruction has long kept weapons locked away. Now, in invading Ukraine, Russian President Vladimir Putin has conjured the spectre of nuclear war for the first time in decades, threatening the West with extraordinary consequences if they interfere, and taking the rare step of putting Russia’s nuclear defences on alert. Though neither side wants nuclear war, analysts warn Russia may yet consider using smaller, localised nuclear weapons to beat Ukraine into submission. Even a nuclear bluff could rapidly spiral out of control, as could conventional attacks on Ukraine’s nuclear power plants.
Addressing Australia’s parliament from Kyiv on March 31, Ukrainian president Volodymyr Zelensky warned that Russia’s “nuclear blackmail” now loomed over all countries, the fears of the previous century reawakened. “What is happening in our region has become a real threat to your country and your people as well,” he said.
So, are nuclear weapons likely to come into play? How would the West respond? And does nuclear deterrence still work today?
What are nuclear weapons and who has them?
To understand the world’s most powerful weapon you have to start on a very small scale. Atoms are the building blocks of matter, and the nucleus of each is held together by a powerful force. In 1938, the race to harness this energy in an atomic bomb kicked off when two scientists accidentally split apart uranium atoms in Nazi Germany. Fears that the Nazis would be first to develop such a weapon inspired big investment by both the US and the UK (and interest from their then-ally the Soviet Union).
The atomic bombs that the US unleashed in World War II work through a chain reaction known as nuclear fission – by splitting the atom of isotopes such as uranium and plutonium. During the Cold War, America and Russia made hydrogen bombs thousands of times more powerful than those dropped on Japan using a process known as nuclear fusion which works in reverse – binding together nuclei – in the same way the sun produces energy. (Oppenheimer’s opposition to the development of more powerful bombs later cost him his job.) Modern nuclear bombs use both fission and fusion.
Today nine countries have nuclear weapons – the US, Russia, China, France, the UK, Israel, India, Pakistan, and North Korea – but the US and Russia hold 90 per cent of the world’s nuclear arsenal. (That’s estimated at 6000 nukes for Russia and more than 5000 for the US compared to a couple of hundred held by China, France and the UK, and only a few dozen for North Korea.)
