Arthur C. Clarke suggests, in a half joking manner, that supernovae may be industrial accidents of alien civilizations who were tinkering with a technology they didn't understand.

It reminds me of the time that there was an advance in particle physics, and some new TeV collider was being built. Some people thought that if a certain particle would be created there would instantly be a massive black hole where Earth was. After checking the figures vigorously, they realized that that conclusion was false.