Updated: Jul 21
#44 Science in History
1st March 1954
On this day, 06:45 local time, the Marshall Islands were flooded with the light emitted by the United States’ first thermonuclear bomb.
“If the radiance of a thousand suns were to burst at once into the sky, that would be like the splendour of the Mighty One... I am become Death, the Shatterer of Worlds.”
- The Bhagavad Gita
‘‘Bravo’, the first thermonuclear and largest weapon to be deployed by the United States, was part of Operation Castle, a series of nuclear tests conducted at the Bikini archipelago (part of the Marshall Islands) in the Pacific Ocean. The Bravo test had a yield of 15 megatons of TNT, which was 1,000 times more powerful than the bomb dropped on Hiroshima in 1945.
Engineers made design modifications to the device which had unexpected consequences. The modification produced an extra source of tritium, greatly increasing the expected yield (one of the atolls was completely vaporised). Fallout from the explosion also exceeded predictions and the exclusion zone had to be dramatically increased.
Along with the unexpected high yield, several other factors contributed to the negative impact of the blast. The weather had changed for the worse, for example, but the test went ahead anyway. There was also the failure to conduct pre-test evacuations as a precautionary measure.
Small wonder that the test is considered the worst radiological disaster in US history. The blast had significant environmental and human impacts, particularly on the indigenous Marshallese who were displaced from their homes and exposed to high levels of radiation.
Incidentally, this was not the largest bomb ever detonated. That dubious distinction belongs to the 27-ton ‘Tsar Bomba’, ‘King of Bombs’, detonated by the Russians over Novaya Zemlya Island in Northern Russia. The 1961 test is estimated to have been 3,800 times the strength of ‘Little Boy’ (dropped on Hiroshima).
‘Tsar Bomba’ had a parachute to slow its descent, allowing more time for the plane that dropped it to get away and escape the blast area!