2014-01-14 – If I understand my Roman calendar (which I may not), tomorrow is the Ides of January. Long months have the Ides on the 15th of the month. Short months, like February, have the Ides on the 13th. Fortunately, Valentine’s Day is not the Ides of February. I’m not sure what happens with medium length months. For some reason, I don’t think that the Ides goes to the 14th, but I’m not sure and I’m too lazy to check Wikipedia for this one.

If you are wondering what the Ides is, let me tell you. The Ides is what happens to a natural phenomenon (the full moon) when it gets the bureaucratic treatment.

You see, months originally followed the cycle of the moon. Months began with the new moon, and you could tell if a month was beginning if you looked in the sky near sunset because you would see a tiny sliver of the moon setting in the West. Each day that sliver would get larger and larger and it would move to the East. After about two weeks, at sunset, you would see a full moon rising in the East.

The Roman bureaucrats didn’t like that simplicity. The lunar cycle is not an integer number of days. The bureaucrats didn’t like that. And if you think there are 12 month in a year, forget that. Twelve lunar months is only 354 days. The Roman bureaucrats bumped this up to our standard 365 days (with a leap year every four years).

I’m not saying this wasn’t a good idea. The Islamic calendar is a strictly lunar calendar, so it falls short by (approximately) 11 days every year. This means that the holy month of Ramada slides back 11 days every year compared to the Roman calendar—and compared to the seasons of the year. Over many years, Ramadan is celebrated in all the seasons of the year.

Could you imagine this happening to Christmas? Or Passover? Passover is explicitly a Spring holiday. It would never work to celebrate Passover in December. The Jewish calendar is a lunar calendar like the Islamic calendar, but we stop the slippage by periodically adding an entire leap month. This year is a leap year on the Jewish calendar. The extra month—Adar II—will be inserted later this winter.

The Roman bureaucrats stopped the slippage of their calendar through the seasons not by inserting leap months but by lengthening each month by approximately a day. But that means that calendar months no longer synch with the phases of the moon.

You can see this in the way the phases synch with this month of January. January 1 was actually a new moon. The calendar was in synch, but this is rare. The next new moon will be January 30, however, two days too early for February. The slippage will continue through the year so that, if you pick any arbitrary month, you have to do complicated calculations to find out when the new moon will occur. With a lunar calendar, you know that the new moon will roughly coincide with the first day of the month. (I say roughly because fractional days in the moon’s orbit may make it slightly off, but not much.)

The odd thing is that, when the Romans adopted the stretch-months, they still retained a day that represents the full moon. That’s the Ides. This month, since the new moon fell on the first, the full moon falls close to the Ides (but not exactly). Obviously, this only happens once in a while, but mostly not.

Before I finish, I want to let you know one other thing about the Roman calendar. Not only were their months one day longer, but so were their weeks. They had eight days a week.

Just like the Beatles.