7. How does The Doctor age?
This issue doesn’t necessarily concern how many birthday candles should go on The Doctor’s cake (that’s a whole other pernickety fire-hazardous mystery), but how Time Lords actual age.
It simply doesn’t make sense: why did Matt Smith’s Doctor look so young on his ‘farewell tour’ (the 200 years he lives through in series six), but then become an old man while defending the town of Christmas on Trenzalore for 300 years in The Time of the Doctor?
One fan theory suggests that Gallifreyans only age when they remain in one time – conversely, they don’t age while travelling through history, thanks to exposure to the time vortex.
At first this theory seems convincing and answers why the First Doctor, who lived the majority of his life stuck on Gallifrey, looks so old. But it doesn’t explain the differing life spans of The Doctors.
We can be fairly sure the First Doctor died from old age (he says “this old body of mine is wearing a bit thin” before regenerating), despite being physically a lot younger than Matt Smith’s Doc on Trenzalore. We can’t be certain of the First Doctor’s exact age at his death, but as the Second Doctor claims his age as “something like” 450 years, it’s probably less than that.
So, the solution? Well, there isn’t really a credible one yet. But hey, you never know, upcoming episodes could finally put an end to the problem Sure, it’ll probably give its own canon a kick right in the Romanas in the process, but that’s simply the timey-wimey-wibbly-wobbly Doctor Who we’ve all learned to love.