"I am uncertain," Celestia said with a small frown. "It could be a coincidence. Though, if that were the case, it would be one the likes of which neither I nor my sister have felt in all the centuries of our lives, or read about in the histories of our world. If we discard coincidence, though, then we must look at it as either the result of a natural change or as a deliberate action. We may be facing some kind of inter-dimensional catastrophe, or we may be on the verge of an invasion from another world." 