about how many days are in an earth year and how many hours in an earth day
Leap years are needed to keep our modern day Gregorian calendar in alignment with the Earth's revolutions around the sun. It takes the Earth approximately 365.242189 days â or 365 days, 5 hours, 48 minutes, and 45 seconds â to circle once around the Sun. This is called a tropical year, and is measured from the March equinox.