In response to the Soviet atom bomb, President Truman announces a crash programme to develop a hydrogen bomb

Erwin Müller completes his development of the field ion microscope, the first instrument capable of observing atoms

The first hydrogen bomb is successfully tested by the US at Enewetak Atoll in the Marshall Islands

X-ray crystallographer Rosalind Franklin, working at King's College in London, photographs DNA

The first Soviet hydrogen bomb is successfully tested at the Semipalatinsk Test Site in Kazakhstan

US physicists Arno Penzias and Robert Wilson discover cosmic background radiation, lending strong support to the Big Bang theory

British physicist Stephen Hawking describes how black holes can emit radiation, a process now known as 'Hawking radiation'

British physicist Stephen Hawking explains the cosmos for the general reader in A Brief History of Time: from the Big Bang to Black Holes

Gravitational waves are detected for the first time, by LIGO