Back in the summer of 1962, the US government set off the only hydrogen bomb ever to blow up in space. Here are some newly-released images that reveal the lightshow people saw back on Earth.

This is from a report on NPR, using recently-declassified images collected by Peter Kuran, who made the documentary Nukes In Space:

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According to NPR's Robert Krulwich:

The plan was to send rockets hundreds of miles up, higher than the Earth's atmosphere, and then detonate nuclear weapons to see: a) If a bomb's radiation would make it harder to see what was up there (like incoming Russian missiles!); b) If an explosion would do any damage to objects nearby; c) If the Van Allen belts would move a blast down the bands to an earthly target (Moscow! for example); and - most peculiar - d) if a man-made explosion might "alter" the natural shape of the [Earth's magnetic] belts.

That's right - the plan was to actually see if we could change the planet's magnetic field - a field, by the way, that protects us from deadly radioactive particles borne on the solar wind. Awesome. Erm, I think. (Thanks, Gregory!)