In the Gregorian Calendar, a common year has 365 days. Every four years there is a leap year, where the month of February has one extra day, and thus on a Leap Year, there are 366 days.

The time period of a Day is determined by the time it takes the Earth to completely rotate on its axis, and are measured through the time it takes the Sun to reach its highest point in the sky, twice consecutively.

The Earth takes 12 months to complete one turn around the Sun. These months correspond to a whole year and are divided into units of 28, 30, or 31 days. So, one solar year is actually 365.25 days long, or 365 days, 5 hours, 48 minutes and 46 seconds.

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