By Peter Weiss
Think of a black hole. No one has ever observed one directly, but chances are that you envision some gargantuan jet-black entity that’s far, far away and insatiably consuming any matter or light that comes near it. Some physicists whose job description includes thinking about black holes have conjured up another possibility. They’re suggesting that extremely tiny, lightweight versions of these exotic objects could be forming right over our heads when ultra-high-energy particles, called cosmic rays, from space strike atoms or molecules in the atmosphere. Those newly created black holes would then quickly decay, harmlessly raining subatomic particles down onto our planet and ourselves.
“Black holes popping up in the sky is a very spectacular possibility,” says theorist Jonathan L. Feng of the University of California, Irvine. If it turns out to be true, some scientists say they might be able to mass-produce black holes in particle colliders.