Doctor Who Series 10: 7 Big Questions We're Asking After 'World Enough And Time'

For those who prefer science-fiction over fantasy the central conceit of World Enough and Time will have been a welcome tonic to the likes of the Moon-egg in Kill The Moon. There is a lovely piece of real science behind this week’s episode that would surely even please the science orientated former script-editor Christopher H Bidmead who once claimed that ‘the sonic screwdriver was magical-baggage we had to lose.”

Explaining the science of time dilation is the easy part. Because of its immense gravitational pull the closer an object is to a black hole the slower the passage of time. On a ship as vast as 400 miles long a 100 miles wide time could theoretically pass much faster from one end to the other. Even on Earth we are subject to a similar effect, though to a much lesser extent. Unless we spend most of the time upside down, our heads will age just a fraction faster than our feet.

It’s not quite so easy to explain why the Doctor is unable to at least partially circumvent the effects. The Doctor’s explanation about why the TARDIS cannot be used seems all too convenient to the plot ("this close to a black hole we'll never able to pilot her accurately" which didn't seem to have been a problem in Time Crash, The Satan Pit of The Family of Blood). But even outside the TARDIS, as a Time Lord we have seen the Doctor transcend the usual laws of time and space (Invasion of the Dinosaurs, Robot, The End of the World).