These leave behind a dense object known as a pulsar, which forms from the core of the exploding star.

ECONOMIST: Research from the beginning of time

The possibility of a supernova - an exploding star - was put forward, but then ruled out because the debris from such an event would still be visible in telescopes today.

BBC: Gamma-ray burst 'hit Earth in 8th Century'

That turned up Nuance Communications (NUAN), which counts Amazon (AMZN), Apple (AAPL), Samsung, Sony (SNE), FedEx (FDX), and On-Star among its exploding customer base.

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