In January, a Vanderbilt University astronomer (I forget her name) found that there were probably hundreds of 'rogue' black holes flying about our galaxy. She surmised that the risk to the earth from these RBH's was infinitesimal. She said that the only possible risk would be that one goes through the Oort cloud and flings something in our direction, but even then, the odds of that are one in a quadrillion per year. But I'm skeptical. How can the RBH going through the Oort cloud be the only possible risk? Couldn't it just head straight for earth, or at least in a trajectory that would either throw earth off its orbit or hurl something towards it?