You know those black holes the Large Hadron Collider was going to make and kill us all? Well, not only are we still here, but the LHC doesn’t seem to be making black holes at all—their decay signature is markedly absent from the data collected so far.
While that is good for those of us who want to keep living (we jest—the hypothetical micro black holes posed no danger), it’s also helping physicists make up their minds about how many dimensions there are in our universe. The lack of black holes at the LHC nullifies some of the wackier versions of string theory which depend on multiple dimensions.
“In order for the LHC to produce some of these black holes, we really have to go beyond the normal theory of gravity,” [CERN theoretical physicist Michelangelo Mangano] said [two years ago]. “We have to assume that there are extra dimensions. By the way, there are many theories that have extra dimensions. Not all of them would give rise to black holes at the LHC. It’s only highly fine-tuned ones that make this possible.” [CosmicLog]