Synchronicity: A parallel world with two moons in a book named after a year

Regular readers will know that I just recently read Whitley Strieber's 2007 novel 2012: The War for Souls. While it has a certain Strieberian charm that kept me reading to the end, it is basically a very poorly written book, and I can't recommend it. The story has to do with three versions of earth that exist in parallel universes. One of these is the earth we know. Another is a world in which the dinosaurs never went extinct but rather evolved into a race of (mostly) evil humanoid reptiles. The third is very close to our world but has several differences; they have McDonald's, for example, but it has "emerald arches" rather than golden ones, that sort of thing. (They also had no World Wars and no Communism -- but inexplicably somehow still had a Manhattan Project and have the hydrogen bomb! As I said, it's poorly written.) The most obvious difference, though, is that this parallel earth has two moons -- and "two-moon earth" and "one-moon earth" are used throughout the novel to refer to these two similar worlds.

Meanwhile, back in the real world, it just so happens that NASA has recently discovered a tiny asteroid that has been orbiting the earth for a few years, and the press is hyping it a "second moon" despite its diminutive size (just a few meters wide). I discovered this a few days after finishing 2012 when Vox Day linked to a news story about it, titling his post (qv) "We're living in 1Q84."

I knew that 1Q84 was a novel by Haruki Murakami, and that the title is equivalent to 1984 (the Japanese word for "nine" sounds like the English name of the letter Q) but had not read it and knew nothing else about it. (I read A Wild Sheep Chase years ago and enjoyed it, but not enough to try anything else by the author.) A bit of Googling revealed that, just like Strieber's 2012, it is about a parallel earth that has two moons.

Reading the Vox Day post so shortly after finishing 2012 was a coincidence, but it's also a coincidence that two novels were written within a few years of each other -- by very different authors in different countries -- but each with a year as the title, and each featuring a parallel two-moon earth. Strieber's novel was published in 2007; Murakami's in 2009 and 2010 in Japanese, with the English version following in 2011. Therefore, any direct influence would have to have been from Strieber to Murakami rather than vice versa, which seems highly unlikely.

It occurs to me that the film 2010: The Year We Make Contact -- released in 1984, just as the final volume of Murakami's 1Q84 was released in 2010 -- also has a plot that revolves around two moons, in this case two of the moons of Jupiter, not those of a parallel earth. Coincidence, or deliberate homage?