10 Common Expressions in English

Leap year: 2012 is a Leap Year

Upcoming Leap Day: 29 February, 2012

A leap year consists of 366 days, as opposed to a common year, which has 365 days.

During Leap Years, we add a Leap Day, an extra – or intercalary – day on February 29. Nearly every 4 years is a Leap Year in our modern Gregorian Calendar.

Why do we need Leap Years?

Leap Years are needed to keep our calendar in alignment with the Earth's revolutions around the sun.
It takes the Earth approximately 365.242199 days (a tropical year) to circle once around the Sun.

Note: The illustration is not to scale.

However, the Gregorian calendar has only 365 days in a year, so if we didn't add a day on February 29 nearly every 4 years, we would lose almost six hours off our calendar every year. After only 100 years, our calendar would be off by approximately 24 days!

Source :
http://www.timeanddate.com/date/leapyear.html

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