The Fourth Dimension

Day of the Moon

Day of the Moon introduces us to 'Eye Patch Lady', a mysterious figure we will see again soon... She's played by Frances Barber whose previous credits include Boudica (aka Warrior Queen) which starred Alex Kingston as the eponymous historical leader.

In Day of the Moon we're reminded that references to the Silence can be found as far back as the Eleventh Doctor's first story. These reminders are achieved through flashbacks to two episodes from the last series - The Eleventh Hour and Vampires of Venice.

At one point Mr Nixon reminds Gardner, 'Son, I am your Commander in Chief.' This title is conferred on all US Presidents according to Article II of the American Constitution. It refers directly to the President's overall leadership of his nation's military forces.

As they part company, the Doctor cheekily asks Nixon to deliver a message! He asks 'tricky Dicky' to say 'hi' to David Frost for him - a reference to the famous interviews between Frost and the (by then) former President Nixon, conducted in 1977.

Day of the Moon is the first time we've seen the Doctor with a full beard. (Not including his 'beard' in The Leisure Hive. That was a time beard). In The Masque of Mandragora we learn that the TARDIS does contain a shaving mirror and in Time Crash the Tenth Doctor tells the Fifth Doctor to take a look at his bone structure '...because one day you're going to be shaving it!'

The Prequel to The Impossible Astronaut was shot on 11 November, 2010. Other scenes shot that day included the scene in the 'perfect prison' when it's revealed that Amy and Rory are alive! These sequences were shot metres from each other as the Oval Office stood about half a dozen paces from the Doctor's cell!

Mark Sheppard plays Canton throughout this entire episode. But when the character first appeared in The Impossible Astronaut he was played by Mark's 'real life' father, William Morgan Sheppard.

In the TARDIS, Rory refers to 'post-hypnotic suggestion'. This is a real-life phenomena where an individual or group of individuals carry out an act or sequence of acts which they have been 'programmed' to execute whilst under hypnosis. They may not understand or even realise what they're doing but the instruction to act is so compelling that their conscious mind may not even resist the order.

Area 51 - the location of the Doctor's prison - is a US military base in Nevada. Some claim it is a research centre where alien technology is investigated and one rumour suggests that since 1947 it houses wreckage from a crashed UFO. The Doctor has visited Area 51 before, unlocking some of its secrets in the animated adventure, Dreamland.

In an early version of the script, when Amy asks Canton, 'D'you even know why you're doing this, eh?' the exchange is watched by three Silence. In the finished version we don't see any aliens during the scene.

Neil Armstrong was the first man on the moon and Buzz Aldrin was the second. There is some debate as to what Armstrong said as he stepped onto the lunar surface. Back on Earth he revealed that what he did mean to say was: 'That's one small step for a man, one giant leap for mankind.' However, for years many believed he omitted the first 'a'. Recent analysis suggests he did in fact deliver the line as intended but the 'a' was virtually inaudible to his audience due to technological limitations.

Renfrew - the unhinged character initially met by Amy and Canton at Graystark Hall - has similarities to RM Renfield, a character in Bram Stoker's Dracula. Renfield was an inmate of a so-called 'lunatic asylum', driven half-mad due to encounters with the ghoulish Count whom he even refers to as 'my master'.

At one point the Doctor declares, 'Very Aickman Road!' This is a reference to The Lodger, and more specifically the alien technology the Doctor encountered when he shared a house with Craig Owens. But is it the same equipment the Time Lord discovered with his friend?