Earth revolves around its own axis in approximately 23 hours 56 minutes 4 seconds. If we measure the length of a day by 24 hours we hour saving 180+56=234 seconds a day. In a year that is 234 * 365 = 85, 410 seconds. In 4 years that is 341,640 seconds. Now a say has 86400 seconds, so we are the end of 4 year we have 341,640/86400 = 3.95 days. But we add 1 day to February after 4 years. Why is this?
In: 2
Short answer: to account for the fact a day refers to the time it takes the sun to be “above” us each time. And we are circling the sun so it takes more than one rotation to have the sun be in the same spot relative to the earth.
Long answer: Think about the earth being at the end of the hour hand on a clock and the sun in the middle of the clock.
Jan 1 the hour hand is at 12, each day the hour hand moves about 2 minutes around the clock face and in 365 days it’s back to 12.
Now in ancient times we didn’t know we were on the the hour hand moving. We thought we were at the center of the clock and the sun was at the end of the hour hand and went all the way around us in a regular amount of time. We silly monkey offspring defined this as “24 hours” and “1 day”.
Eventually we learned the truth. That we are spinning at the end of the hour hand and the sun is the center of the clock. But we still define “a day” as “24 hours” and the length of time it takes for the sun to appear “above” us everyday. But for this to happen the Earth has to spin 360 degrees + 360/365 degrees to still end up facing the sun every “day”.
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