Pacific aurora

In 1962 the United States detonated a nuclear bomb in outer space over Hawai’i. It caused an artificial aurora in the sky over Honolulu – and another one over Samoa, more than four thousand kilometres away.

Aurora over Honolulu
US gov, Public domain, via Wikimedia Commons

During the Cold War, the US government did a lot of nuclear weapon testing, to work out just what they could do with their growing supply of apocalyptic bombs. For a while, they shot nukes into outer space. They actually had a strategic reason to do this: it was thought that the electrons from small nuclear explosions in the atmosphere might form a protective shield against enemy missiles (the so-called Christofilos effect).

Operation Argus in 1958 established that the Christofilos effect didn’t last long enough to be a useful defence. But that whole testing project had been rushed – the US government wanted to get it done before negotiations for a nuclear test ban were opened with the Soviet Union – so they had insufficient data about exactly what happened when you exploded a nuke in space. Four years later, Operation Fishbowl picked up where Operation Argus left off.

Starfish Prime was Operation Fishbowl’s most prominent test – prominent in the sense that it exploded in space near to Honolulu. So close, in fact, that the explosion’s electromagnetic pulse actually knocked out streetlights in the Hawai’ian capital. The electrons from the blast also created a beautiful artificial aurora in the sky over Honolulu. And the effects spread a lot further.

Consider this picture of the Earth’s magnetic field:

Earth's magnetic field
Zureks, CC0, via Wikimedia Commons

All of those high-energy electrons from Starfish Prime caused an aurora in the sky over the blast. Then, they were picked up by the planet’s magnetic field and drawn further out into space. The electrons curved around according to the path of the field and returned to Earth over the Southern Hemisphere. The result: another artificial aurora, this one over islands in the South Pacific such as Samoa and Tonga.

This artificial radiation belt also blew out a few satellites on its way through, including Telstar 1 (an early communication satellite that transmitted the first live trans-Atlantic television), Ariel 1 (the UK’s first satellite), and TRAAC (which carried the first poem into space).

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