The Manhattan Project had assembled some of the finest scientific minds of the 20th century (perhaps any century), including Niels Bohr and Richard Feynman, who were lead by American physicist J. Robert Oppenheimer. They were armed with fresh insights into the structure of – and latent energy within – the atom via the relatively new field of quantum physics. In 1939, Albert Einstein himself had signed a letter to President Franklin D. Roosevelt, warning him of the likely development of new weaponry based on this knowledge, and urging the U.S. to begin stockpiling uranium on this basis.
The culmination of the project came on that July morning, when ‘the Gadget’ lit up the morning sky in an explosion which dwarfed the impact of any previously constructed weapon (the image above, taken 16 milliseconds after the device was triggered, shows the fireball with a height of around 200 metres).
The sight of the massive fireball reminded Oppenheimer of a line in the Hindu scripture, the Bhagavad Gita (Oppenheimer learned Sanskrit in 1933 and read the text in its original language; the scripture became a cornerstone of his personal philosophies):
If the radiance of a thousand suns were to burst at once into the sky, that would be like the splendor of the mighty one …
But Oppenheimer was also moved to think of another, much darker line from the Gita, which reflected how much the world had changed with this successful test; how much power now lay at the hands of humans. In 1965 he discussed what came through his mind at the time of the test on a documentary, and the famed physicist was visibly emotional:
We knew the world would not be the same. A few people laughed, a few people cried. Most people were silent. I remembered the line from the Hindu scripture, the Bhagavad Gita; Vishnu is trying to persuade the Prince that he should do his duty and, to impress him, takes on his multi-armed form and says, ‘Now I am become Death, the destroyer of worlds.’ I suppose we all thought that, one way or another.
Interestingly, other people involved in the Manhattan Project have noted that, to their eyes, Oppenheimer’s reaction to the successful test was more of relief, and some triumphalism. This would be understandable – Oppenheimer was under a lot of pressure to ‘deliver’, and seeing the project come to fruition would certainly have relieved that stress.
But with the weapon being put to use within 3 weeks against Japan, guilt over the deaths of more than 100,000 people likely weighed heavily on him for the rest of his life. Richard Feynman’s reactions at the time of the test, and then post-war, seem similarly contrasted:
