Doctor Who: 6 Things That Explain The Matt Smith Era

4. The Cracks In Time

The cracks were erasing time. The explosion of the TARDIS caused a major gravitational collapse, but given that it was a TARDIS dying and not a star, it pulled time as well as space into a black hole, across all realities; hence why it affected the Time Lords' new universe. The Doctor supposedly sealed all the cracks in 'The Big Bang', but how many times have we heard that he's sorted everything out for good this time and closed the story? Well, he hadn't closed the story for good: why was there one lastremaining crack on Trenzalore? Well, given that the Time Lords snapped it shut, it's probably safe to assume that they were the ones that kept it open. They would've ventured through it - they were waiting for the Doctor to confirm it was safe - and remember, the explosion happened at every point in time, which explains why there's a delayed reaction to this particular crack. The Doctor was terrified of the cracks because they threatened all of reality. It's interesting to wonder though how much time actually passed during the Doctor's stay on Trenzalore: if there was a time-eating crack, how can he be sure it was 300 years? What if he aged quicker than time passed? What if it felt like 300 years but was actually ten minutes? Timey-wimey indeed.