"Maybe a black hole could form, and then suck in everything around it," he wrote. "The second scary possibility is that the quarks would reassemble themselves into compressed objects called strangelets." "That in itself would be harmless. However under some hypotheses a strangelet could, by contagion, convert anything else it encounters into a new form of matter, transforming the entire earth in a hyperdense sphere about one hundred meters across." As if this wasn't bad enough, the atom smasher might even be capable of destroying space itself. "Some have speculated that the concentrated energy created when particles crash together could...