It was 60 years ago that strange and alarming phenomena occurred in the Pacific, from Hawaii to New Zealand. Night skies glowed, auroras and rainbow-coloured stripes appeared, radios blacked out and satellites eventually broke down.
The US had detonated a thermonuclear warhead 250 miles above the ground in space on July 9, 1962, launched from Johnston Atoll in the Pacific. The bomb test, codenamed “Starfish Prime”, detonated a 1.4 megaton device, about 100 times more powerful than the Hiroshima bomb, yet scientists underestimated the effects of the bomb and the resulting radiation.
The bomb test created an electromagnetic pulse causing electrical damage in Hawaii about 900 miles away, knocking out streetlights, setting off burglar alarms, blacking out radios and cutting off telephones. The night sky over Hawaii lit up and an eerie glow lingered for four hours afterwards. “It looked as though the heavens had belched forth a new sun that flared briefly, but long enough to set the sky on fire,” according to one account in the Hilo Tribune-Herald. A witness said: “A brilliant white flash burnt through the clouds rapidly changing to an expanding green ball of irradiance extending into the clear sky.”
The explosion blasted the Earth’s magnetosphere with huge amounts of radiation, turning into electrons that rained down on the upper atmosphere. The electrons also smashed into satellites, scrambling their electronics. The effects of the bomb blast lingered even longer. The electrons were trapped by the Earth’s magnetic field, creating an artificial radiation belt around the Earth.
The bomb test came at the height of the Cold War, and three months later the world found itself on the brink of nuclear war during the Cuban missile crisis in October 1962. But Starfish Prime helped to bring about the Limited Nuclear Test Ban Treaty, which was agreed a year later, on July 25, 1963, banning nuclear testing under water, in the atmosphere and in space.