Nuclear weapons and the United Kingdom the year. During Operation Hurricane, an atomic bomb was detonated on board the frigate anchored in a lagoon in the Monte Bello Islands in Western Australia on 3 October 1952. Britain thereby became the third country to develop and test nuclear weapons. This led to the development of the first deployed weapon, the Blue Danube free-fall bomb. It had a diameter, 32 explosive lens implosion system with a levitated pit suspended within a natural uranium tamper. The warhead was contained within a bomb casing measuring diameter and long, and it weighed approximately , of which about was high explosive. The
Atomic clock of using atomic transitions to measure time was suggested by Lord Kelvin in 1879. Magnetic resonance, developed in the 1930s by Isidor Rabi, became the practical method for doing this. In 1945, Rabi first publicly suggested that atomic beam magnetic resonance might be used as the basis of a clock. The first atomic clock was an ammonia absorption line device at 23870.1 MHz built in 1949 at the U.S. National Bureau of Standards (NBS, now NIST). It was less accurate than existing quartz clocks, but served to demonstrate the concept. The first accurate atomic clock, a caesium standard based on