Bungie hasn't explicitly mentioned anything about server locations, the number of servers, or anything even regarding them since the beta. And even then, most of it was just that they were testing them. I'm not sure that any major games, especially one with a worldwide reach like Destiny seems to have, can survive off of just one server. The latency problems alone would cripple the game for at least half the population and finding an open server room would be impossible. It is fairly safe to say that there will be at least two or three for every major land mass (i.e., North America, South America, Europe, East Asia, Australia, etc.). Beyond speculation, there is little to nothing to go off of without finding a Bungie employee in person and having them show you a map or an invoice or something.