Michael McMurray, age 11, of Seattle, Wash., for his question:
Why is there a February 29 every four years?
Today is leap year day and several thousand new babies will be barn. Must the poor little darlings wait four years to celebrate their first birthday party? Not at all people born on leap year day have a choice. They may celebrate on February 28 or March 1 for three years. Once in every four years they have a birthday on February 29.
Our calendar is based on the earth’s rotation around its axis and its revolution around its orbit. It rotates once in about four minutes short of 24 hours. With each rotation it faces the sun with first one side then another, which gives us a day and night. Each day and night period is one date on the calendar.
The calendar year is based on the solar year the time it takes the earth to orbit from one spring equinox to the next. This period of time is 365 days, five hours, 48 minutes and 45.575 seconds. This is a little short of 365 and a quarter days, It is that quarter day which upsets the calendar. For the yearly calendar must be a number of days of equal length.
It takes four of the misfit quarter days naturally to make up a whole day. So we simply save up three quarter days from three years and add them to the quarter day in the fourth year. We now have a whole day, a date which we can add to the calendar. We give this extra leap year day to poor little February which, as a rules has only 28 days.
Leap year fells every four years on a year whose number can be dividedby four. This is why 1960 is a leap year. But, remember, the solar year is a little short of 365 days. Through the centuries, this slight difference could pile up and throw our calendar into confusion.
This is adjusted with the centurial years, those whose numbers end with two zeros. We have a leap year only when a centurial year can be divided by 400. The next centurial year was 2000 and, since this number can be divided by 400, the year will be a leap year. The centurial year following will be 2100. We cannot divide this number by 400 and have the answer come out a whole number, hence the centurial year 2100 will not be a leap year.
Even so, our calendar is not perfect. In 4000 years there is an error of almost a day. What's more, the number of days in the months is haphazard. There is talk of a calendar reform on a world wide basis. This new calendar would save untold hours of bookkeeping and simplify countless pages of records. So, let's hope that the United Nations will make us a present of this new streamlined calendar. It is suggested that in this up date calendar, leap year day will be a world wide holiday.