![[Peter Capaldi on the moon]](/blogpics/themoonsanegg.jpg)
So on [[wiki:Kill the Moon|this week’s Doctor Who episode]], the Doctor asserts a couple times that the moon is 100 million years old. This, along with a lot of other Jack Kirby-esque science nonsense, irritated a great many viewers. Like this respected and lovely local author on Twitter:
Speaking of the moon, if you are doing a science fiction story in which the mass and age of the moon are plot points, LOOK THEM UP, Moffat.
— Erin Bow (@erinbowbooks) October 7, 2014
In *our* universe, the moon is about 4.5 *billion* years old, give or take a few hundred million–there’s still some debate. That information isn’t hard to find. However, I assert he *did* look it up.
![[The History of the Universe]](/blogpics/historyoftheuniverse.jpg)
The Doctor Who universe isn’t our universe. In the *Doctor Who universe*, the arrival in the moon in orbit around the Earth is a specific and important historical event. It did two things: its sudden appearance in the sky convinced the Silurians (aka Homo Reptilia. SCIENCE!) to go into hibernation to avoid the impending doom it almost certainly portended (see: [Doctor Who and the Silurians](http://tardis.wikia.com/wiki/Doctor_Who_and_the_Silurians)), and it destabilized the fragile Earth-[Mondas](http://tardis.wikia.com/wiki/Mondas) twin orbit, sending Mondas drifting into interstellar space (see: [The Tenth Planet](http://tardis.wikia.com/wiki/The_Tenth_Planet) and, in particular: [Spare Parts](http://tardis.wikia.com/wiki/Spare_Parts_%28audio_story%29)).
Putting it at about 100 million years makes some sense for the Silurian timeline (moreso than the Doctor Who History of the Universe’s assertion that the Silurians’ ancestors survived and evolved 20 million years after the [Earthshock](http://tardis.wikia.com/wiki/Earthshock) extinction event that killed the dinosaurs). And it suddenly appearing as described in those stories is nicely in line with what is revealed about the moon in Kill the Moon.
So yeah, the age of the moon, to me, was a delightful callback to previous adventures. The nonsense about the increased mass of the moon was a bit more irritating, but I’ll give them a pass for not wanting to pay for all that wire work.
*Update! 2015-05-05* Writer Peter Harness confirms on this week’s [Radio Free Skaro](http://www.radiofreeskaro.com/2015/05/03/radio-free-skaro-474-mayhem-of-the-mooninites/), episode 474, that the 100 million year age of the moon was, in fact, a deliberate reference to Doctor Who and the Silurians. Validation!
I can understand the frustration of new Doctor Who fans to those kinds of callbacks. Many of the fans of Doctor Who (myself included) are only familiar with the shows made since 2005. That means there is decades of material we just don’t know about and when you have those kind of contradictions… If I was Moffat and I heard this complaint about the age of the moon I would just say “F*** ’em”
It’s a throw-away line which is just nonsense if you don’t know this stuff. And I don’t expect very many people at all know this stuff.
I knew the Cybermen thing because I loved and devoured the David Banks Cybermen book in the 90s where he made the moon stuff up (and Spare Parts adopted the explanation). You wouldn’t be able to make the connection even if you watched attentively through every single TV episode. I’d forgotten about the (way more canonical and pertinent) Silurian thing until I’d thumbed through my well-thumbed History of the Universe, pictured above.