Most years, February 28 gives way to March 1. But not this year!
In 2012, we have a February 29, and we’ll have another one in
2016. What’s up with that? Our calendar year is usually 365
days. This is the amount of time that it takes Earth to travel
once around the Sun. When the Gregorian calendar was introduced
in 1582, a year was defined as 365 days to make the calendar
year coincide with the solar year. Long, long ago, though, smart
astronomers figured out that it actually takes Earth a little
bit longer than 365 days to travel around the Sun. Measuring
precisely, they determined that one trip around the Sun actually
takes 365.242 days (or 365 days, 5 hours, 48 minutes and 46
seconds, to be exact). That means a year should actually be 365
and almost one-quarter days long. Since that would be very
difficult to manage on a calendar, the ancient Egyptians came up
with the idea of adding a day every four years to keep the
calendar year on track with the solar year. The ancient Romans
under Julius Caesar decide