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Today is a Very Unusual Day

It is Groundhog's Day in the year 2000.

It is also a very unusual date in the commonly-used calendar. Starting today, there will be many, many more dates with these special characteristics. As a matter of fact, another one will occur the day after tomorrow. However, today is the first one in a long, long while.

A date with today's characteristics has not occurred for well over a millenium. To be more precise, a millenium, plus one hundred and eleven years, plus five months and a few days have elapsed since a date such as today's last appeared on the ordinary calendars -- give or take a couple of weeks, depending on whether and when one switched from the Julian to the Gregorian system.

Only a few months ago, there was another date with equally unusual characteristics. It had the opposite characteristics of today's date, as did many other dates before it, but it was the last one for a long, long time and another one like it will not occur until a New Years Day early in the 32nd Century.

Today, for the first time since August 28th, in the year 888, it is now possible to write the complete date using even digits only. And, while this has not been possible since the year 888, it can be done today, as well as the day after tomorrow: February 4th, in the year 2000.

[An aside: As most of my friends and colleagues know, for all of my adult life I have written dates with the year first, then the next-largest unit, the month, and finally the smallest, the day of the month. This causes the dates to sort chronologically, and is particularly useful for computer file names.]

I shall write the day after tommorow as:

2000 / 2 / 4

Many in America will write it as:

2 / 4 / 2000
However, in Europe and elsewhere, it will more often appear as something like:

4 / 2 / 2000

Regardless of which notation one uses, it is only the second date in 1111 years does not require any odd digits (1,3,5,7,9) to write numerically and completely. Today was the first.

A few months ago, the 19th day of the month of November was the last of many dates that could be written entirely with odd digits. (I wrote it as 1999/11/19, while others may have written 11/19/1999 or 19/11/1999.) There were many, many other dates like it in the preceeding 1000 years. There will not be another until the first day of the year 3111.

Writing today's date uses only the digits two (2) and zero (0). Some dates are even more unusual, such as Groundhog's Day two hundred and twenty-two years from now. That will be the first date in a very long while that can be written entirely using only one digit. The last one was back in the year 1111, on the date now known as Veterans' Day, 11/11.