Researchers have proposed that black holes stop evaporating at the last moment, leaving behind tiny remnants that preserve all the information they contain. The same seven-dimensional geometry behind this idea could also help explain why elementary particles have mass. The paradox traces back to work by Stephen Hawking in the 1970s. Using semi-classical calculations, Hawking showed that black holes are not completely black. Instead, they emit a faint form of radiation that slowly drains their energy, causing them t... [4846 chars]