“Today
is Day 2 Million”
Marc Cohn,
CTM
Speech
# 7,
January 22, 2004
Fellow
Toastmasters and guests, Today is day 2 million.
Actually, today is January 22, 2004.
On the Jewish Calendar, today is Tevet 28, 5764.
On the Islamic calendar, today is Dhu Qada 29, 1424. Finally, today is day 1 for the Chinese calendar 4702.
What
if we wanted to know what day it was 30 years ago, 60 years ago, 100 years ago,
or 5,700 years ago on different calendar systems.
Where are you going to obtain that information?
The internet has some calendar converter websites.
A second way is to find a synagogue that has old calendars from many
years ago. A third way is to write
a program to convert from one system to another using everyday software such as
Excel.
My
interests in calendar conversions began about six years ago.
I worked for an insurance company in Chicago and was involved in date
calculations. To calculate
reserves, I needed to know how many days there were between two dates.
However, the programming language didn’t have date calculation
functions. Thus, I wrote my own.
Second of all, I was in the information systems department working on the
year 2000 problem. The solution to
the year 2000 problem was easy but tedious.
One needs to go through every program and make sure that date
calculations are being done using 4 digit years instead of two digit years.
One takes the dates from input files, moves them to temporary four digit
year storage areas and calculates the date calculations.
There would be no need to rewrite systems, rewrite file descriptions, or
rewrite reports. It was a tedious
process and there were no shortcuts. However,
we had meeting after meeting about the Year 2000 problem and how we’re going
to solve it. Finally, I decided to
use a sledgehammer to kill an ant (find the most complicated solution to the
problem). I sarcastically suggested
that we write a program to convert all the dates to the Jewish Calendar.
Then, we can rename the problem the year 5761 problem.
I
have recently writen some code in Excel 97 to convert dates from the Gregorian
calendar to the Jewish Calendar and back.
Converting dates from one calendar system to another is a five step process. The first step is to start with Calendar system A (the Gregorian calendar). Make sure that you understand how it works and write coding to convert the dates into a sequential numeric. The sequential numeric has to be calculated so that one understands the day following February 28th is February 29th in some years and March 1st in other years. The sequential numeric has to be calculated in such as way that the day following the calculated day increments the numeric by one. One needs to remember that years 1700, 1800, 1900, 2100, 2200, etc. were not leap years even though they are divisible by four. Also, there was a 10 day adjustment in the calendar in the year 1582. An excellent way to check your calculation is to divide the number by seven and determine the remainder. The remainder represents the day of the week. The world almanac is an excellent source for old calendars.
The
second step is to go the other direction. This
is more complicated because you are taking one number and calculating three
variables with it (month, day, and year). Make
sure you get the same date back after following step 1. Once you complete these two steps, one can calculate the
number of days between two dates, determine the date 200 days from now, and
determine the day of the week for any day.
Steps
three and four are the same as steps one and two except for Calendar B (which I
will call the Jewish Calendar). The
calculation of this calendar is a lot more complicated than the Gregorian
calendar but it is based on the moon. Thus
some months are 29 days and some are 30 days.
In addition, the calendar calculation is based on a 19 year cycle with 12
years having 12 months and 7 years having 13 months.
Once
these steps are completed, we are ready to convert from one calendar to another. Find one date from one calendar its equivalent on the other
calendar such as today’s date in both calendars. Calculate the numeric value using steps 1 and 3 for the date.
On the Jewish calendar, Tevet 28, 5764 is not exactly day 2,000,000 but
day 2,105,029 from the first day in year 1.
On the Gregorian calendar, January 22, 2004 is day 38,008 from December
31, 1899, which is the calculation on Excel.
The difference between the numeric values is the conversion constant.
Thus, the conversion constant is 2,067,021. This constant will then be used to convert from one calendar
to the next for every date. Thus,
if we wanted to know when day one was on the Jewish calendar (first day of year
1, the conversion process would calculate Monday October 7, 3761 BCE (minus
3760).
With the conversion process completed, one can create more interesting calendars. Here are some examples of Gregorian calendars showing the conversion to the Jewish calendar for every day. I used 1939 because my parents were born in that year. Here is also an example of a Jewish Calendar showing all the Gregorian dates for each day. Now one can create calendars showing the dates on the other calendar system without trying to find old calendars. Thank you.