On 2 August 1939 a letter was sent to the President of the United States, F.D. Roosevelt. The letter was signed by Albert Einstein and became one of the most important documents ever written by a scientist. Einstein’s fame extended far beyond his work in physics, he had become an icon of wisdom and humanity. His pacifist views were also well known. This made the so-called ‘Einstein letter’ all the more dramatic because its message was stark and simple: Einstein informed the President that it was possible to build ‘extremely powerful bombs of a new type’ by harnessing the power of the atom. The one-time pacifist suggested a way to create a weapon of awesome destructive power.
Six years later, a bomb was exploded in the New Mexico desert. The scientists who had journeyed to the test site in such high spirits returned as more thoughtful men. What they had witnessed was truly awe-inspiring, but the destructive power turned their elation into concern and fear.
The same question was on everyone’s lips: ‘What have we done? What have we done?’ The answer emerged soon afterwards when atomic bombs were dropped on the Japanese cities of Hiroshima and Nagasaki. Up to 214,000 people were killed, not including those who died later from radiation. Warfare had entered a new and more terrifying age.
Einstein was highly critical of the decision to use the bomb. His letter was prompted by his belief that 'the enemies of mankind' were developing an atomic bomb, and that the only deterrent was for America to make one first. He later said: 'If I had known that the Germans would not succeed in constructing the bomb, I would never have lifted a finger.'
Einstein believed that although Roosevelt might sanction the development of a bomb as a deterrent, he would never agree to its use. Einstein wrote to him, enclosing a strong warning against using the atomic bomb. But the letter was still unopened on Roosevelt's desk when he died. The new president, Harry Truman, was too busy taking office to be accessible, though the scientists tried hard to get through.
In January 1950 President Truman announced that the USA was beginning an all-out effort to develop a hydrogen bomb. The first H-bomb, nicknamed "Mike", was a singularly impractical device. It weighed around 70 tonnes and was as big as a house - but it worked. The blast was hundreds of times more powerful than the atomic bomb explosion at Hiroshima, producing a light brighter than 1,000 suns and a heat wave felt 50 kilometres away.
Subsequent H-bomb tests left a number of islands uninhabitable and local people counting the impact of vast radiation doses on their health: the health effects of the hundred-plus thermonuclear detonations in the Pacific are still an issue.
This is the local legacy of Mike and its descendants. Its global legacy is the vast arsenals still maintained by the nuclear club. Although successive international treaties have sought to reduce the nuclear stockpile, there are still enough hydrogen bombs in the world to destroy humanity many times over.
An ivory-tower mentality was perhaps tenable in the past when the times of a scientific finding and its practical application were well separated. However, the tremendous advances in science during the 20th Century have made it a dominant element in our lives, bringing enormous improvements to the quality of life, but it has also created grave perils. Above all, science has produced a threat to the very existence of the human species through the development of weapons of mass destruction.
Many scientists maintain that there is a distinction between pure and applied science; that it is the application of science that can be harmful, not the study, and Einstein understood this, saying: 'We must not condemn man because his inventiveness and patient conquest of the forces of nature are exploited for false and destructive purposes.'
The price of progress must be eternal vigilance. As Einstein said, our fate depends entirely on our sense of morality.
After the atomic bomb was dropped on Hiroshima, someone said that it was the tragedy of scientists that their discoveries were used for destruction. It's not the tragedy of scientists. It's the tragedy of mankind.