Many
happy returns to the three
children of Norway's Henriksen
family – Heidi (b. 1960), Olav
(b. 1964) and Lief-Martin (b.
1968)
– who all celebrated their
birthdays this year. What's so
unusual
about this? They were all born
on Leap Day, February 29, the
most siblings to do so.
Leap
days are necessary because there
are not precisely 365 days
in a year. The exact figure is
365.2425 days, which means that
we
gain an extra day every four
years.
During
the reign of Emperor Julius
Caesar, when there were only
355 days in a year, the seasons
would get out of sync with the
calendar. Caesar decreed that
the calendar be revised, a new
month
be added in his name (July), and
an extra day added every
four
years
to keep the calendar and seasons
together. The date of
February
29th
was chosen as the 28th was then
considered the
last day of the
year.
Most
Generations Born on Leap Day
The only verified example of a
family producing three
consecutive
generations born on February 29
(Leap Day) is that of the
Keogh's.
Peter Anthony (Ireland, b.1940),
his son Peter Eric (UK, b. 1964)
and his grand-daughter Bethany
Wealth (UK, b. 1996) all
celebrate
their birthdays infrequently
(every four years).
There are a total of 1,461 days
are in each four-year period, so
the
probability that a person is
born on February 29 is 1 in
1,461. But,
it's not quite this simple.
If a year is divisible by 100
then it is a leap year only if
it is also
divisible by 400, so
between the years 2097 and 2103,
your chance
of being born on
Leap Day is zero.
The
Leap Day was introduced in 46
BC, but it was discovered in
10 BC that the priests
responsible for maintaining the
calendar
had
added too many – once every
three years, instead of the four
decreed
by Julius Caesar. To compensate,
there were no more
leap days
until AD 8.
Since
then, there have been leap years
every year divisible by 4,
except
for those years that can be
divided by 100 but not
400.
