Multiples of 5

What's the obsession with multiples of five?

The fifth anniversary of the events of Sept. 11, 2001 was yesterday and remembrances abounded. Every media outlet featured something emphasizing that we're "five years out." If this wasn't obvious from the weeklong transformation of the History Channel from WWII TV to 9/11 24/7 or from the stupid controversy over ABC's stupid 9/11 mini-series or from President Bush's 17 minute (!) address, it became abundantly clear to me when I visited ESPN.com yesterday and found in their "Spotlight" section a feature on 9/11. Here are two of the story descriptions:

Gene Wojciechowski was ready for some football. But his heart just wasn't into MNF. It's still at the corner of Vesey and Church. (a.k.a. Ground Zero).

The nightmares still return. The acrid smell, too. Mark Dodge was at the Pentagon on 9/11, and the Aggie football player's life is shaped by it.

I understand the need for a remembrance, an assessment of the ramifications of 9/11, maybe an update on our safety for nervous Moms and Dads, but why is Five so much more significant than, say, the fourth or sixth anniversary? If anything, the fourth anniversary has a more immediate connection. Why should half a decade be more significant than the other anniversaries? I assume that we'll see 9/11 anniversary coverage decline for the next four years and then have an unimaginably big spectacle for the 10th anniversary.

But why should this be the case? Why do multiples of 5 of such symbolic significance in our culture? We see this phenomenon with birthdays, too. Your 25th and 30th birthdays are surprise party birthdays, but the 26th and 31th are dinner out with a few friends birthdays.

I assume that the centrality of the number five stems from the fact that we have five fingers on each hand. Of course, the more commonly occurring number of any given body part is two (e.g., two legs, two arms, two eyes, two ears, etc.). And I seem to remember from Sunday school that seven is a particularly central number in the Bible. Given that Bush is a Christian and that the seventh anniversary of 9/11 will fall in his last year in office (an presidential election year), maybe we should be expecting an extra special anniversary in 2008. Come to think of it, I wouldn't be surprised at all if the scope of the remembrance followed to a two -- not five -- year pattern from here on out.