Its also entirely likely that theyll be a whole lot of warfare breaking out across the universe when that happens. Where The Doctor does tend to be rather effusive about his love for humanity and our speciess capacity to do great things, one of the negative aspects of the race that is constantly returned to is our propensity for war. Where The Doctor is an avowed pacifist, he is forever disappointed by us apes and the urge to do violence upon each other, something which continues even when tanks have been swapped for space ships. To be fair, it isn't always humanitys fault. Spreading across the cosmos will pique the attention of aliens with whom we never signed a peace treaty, which inevitably leads to invasion. In Doctor Who the Daleks have tried to invade the colonised Venus in the year 17,000, the Sontarans tried to half-inch the entire galaxy whilst most of humanity was in stasis, the Platonic War that killed thousands happened in the book The Slitheen Excursion, and apparently the most peaceful time in human history wont be until 500,000,000 AD. Unfortunately, this will probably be one of Doctor Whos most accurate predictions.