ARE mini black holes raining down through the Earth's atmosphere? It's possible, says a team of physicists. They think this could explain mysterious observations from mountain-top experiments over the past 30 years.
Ordinary black holes form when stars explode at the end of their lives. The heavy stellar core can collapse into a superdense "singularity" whose gravity is so strong that nothing - not even light - can escape.
If some of physicists' favourite theories about extra dimensions are correct, it would also be possible for high-energy cosmic-ray particles from space to create black holes when they collide with molecules in the Earth's atmosphere (