Not doing this experiment again soon: 60 years ago the US created the first man-made aurora and EMP

h/t Tallbloke

Starfish Prime was the largest Nuclear test conducted in space. The 1.4 megaton explosion at 250 miles above Johnson Atoll was a US mission that launched on July 9th 1962. The Electromagnetic pulse (EMP) it generated was much bigger than expected, and knocked out a few satellites, which presumably wasn’t part of the plan. (Future tests were smaller.) The explosion and the aurora it generated was visible nearly 900 miles away in Hawaii where some street lights were blown, some phone lines went down and surges were recorded on planes. Apart from war, it’s hard to imagine this experiment could be done ever again.

The aurora itself lasted less than 15 minutes, but created a belt of MeV electrons. And as many as five years later some of those electrons were still being detected in the atmosphere.

Starfish Prime: The First Accidental Geomagnetic Storm

Dr Tony Phillips,

On July 9, 1962, the US military detonated a thermonuclear warhead 250 miles above the Pacific Ocean–a test called “Starfish Prime.” What happened next surprised everyone. Witnesses from Hawaii to New Zealand reported auroras overhead, magnificent midnight “rainbow stripes” that tropical sky watchers had never seen […]