Spoiler Level: Very, Very High
First off, let me just say "Wow" and scrape my jaw up off of the floor. This season is really taking the long view for its story arc, following up on unresolved plot threads from last season and laying lots more for the rest of this season. At least, I hope they're going to be resolved this season. I think this episode raised more questions than it answered.
So okay, "Silence will fall" is referring to this species, the Silence, who have been running the human race for thousands of years. I've got mixed feelings on that; on the one hand, I hate it when SF attributes all of humanity's achievements to alien influences. I feel like it cheapens us as a species, and takes away the pride in our accomplishments. This episode is a perfect example-- we didn't go to the moon because we wanted to, but because the Silence wanted us to. Heck, did we even develop the technology to do it on our own? But on the other hand, the concept that they've been in control of humanity for all of recorded time is truly terrifying. The concept that we could be being controlled, rise up in revolution, overthrow our controllers and then never remember any of it because it all happens "between the scenes" of our normal lives is just mind-blowing.
But all that leads to another unresolved point: Why did the Silence want us to go to the moon? Is it only so they could create the Impossible Astronaut's space suit?
Along those lines, we now know that the Impossible Astronaut is a self-controlled, self-healing spacesuit, presumably created by the Silence, created for the purpose of containing the little girl. And... that's it.
Unanswered questions: why? Which I guess leads us to...
Amy's pregnancy: Okay, she didn't tell Rory because she was afraid there might be something wrong with the baby. Nice answer. Now to the implied answers-- I was under the impression that the Silence took her baby, and she has no memory of it, and the little girl was in fact her child, based on the photos Amy found in the orphanage. Then the kid goes and regenerates, and the TARDIS keeps reading Amy as both pregnant and not pregnant. Oookay. A "time head" indeed. As we were discussing the episode after wards, a friend of mine hit upon the idea that the little girl might be The Doctor's and River's daughter, and that the photo was actually of Amy holding their baby. I rather like that idea, but I suspect it won't be as simple as that (if that is at all simple).
So the unresolved questions are who is the little girl, who are her parents, and what's Really Going On with Amy's pregnancy?
Poor River. The Doctor's really getting comfortable with her, even falling in love with her, and as it's beginning for him it's ending for her. I have to say I'm not totally thrilled with the idea that they're always moving in reverse order; I rather liked the idea that it's more of a jumble. Maybe she only thinks it's in reverse during this meeting? Or perhaps Steven Moffat prefers to do it in reverse order so it's easier for him to keep it all straight in his head. All I know is that he better have this all written down somewhere so it all makes sense when he's all done! I look forward to rewatching all of River's stories in order from her perspective when that day comes.
Nothing really new about the unanswered questions about River; it's the usual stuff, is she really the Doctor's wife, and who did she kill and why did she kill him/her?
As to which episode title should be considered the story title-- that's a bit of a tough one with this story. On the one hand, the actual "Day of the Moon" refers to July 20, 1969, where the bulk of this episode takes place, which would seem to make it a more episode specific title, whereas the Impossible Astronaut was very prominent in both halves and is the catalyst for the entire thing. Put all that together and "The Impossible Astronaut" should probably be the story title. On the other hand, The Apollo 11 and Silence stories are the only plot lines that are wrapped up, and we're still not really any closer to understanding just what the Impossible Astronaut itself is, so from that perspective "Day of the Moon" might make a better story title. But for me personally, since "Day of the Moon" is more episode specific, "Impossible Astronaut" wins out.
And now I'm off to read Jonathan's latest "Eleven for Eleven" installment for this episode over at Dislocated Life. Yeah, I'm recommending it sight-unseen, but you can always trust Captain JLS. I generally try to do my own write-ups before reading anyone else's so I can be sure my opinions are really mine. You never knew when some outside force is influencing you...