Curio #255 | The difference a day makes A daily curious fact from Justin Kitch, Curious CEO Prepare to have your celestial mind blown. We all know a days length is derived from the time it takes the earth to make one rotation: 24 hours. Wrong! The earth rotates completely every 23 hours, 56 minutes and 4 seconds. Called a sidereal day, this is also the time it takes stars to reach their highest point in the sky--the celestial meridian--on any two consecutive days. The four minute difference is the reason constellations appear to march westward throughout the year. But, 24 hours is exactly the time it takes the sun to reach its celestial meridian. The extra four minutes is how long the earth must keep rotating to perfectly re-position the sun in the sky, compensating for the 1.5 million miles we travelled in our orbit since yesterday. If you add up those four minutes for an entire year, you get exactly one extra rotation that the earth makes. So it takes us 365.25 days to travel around the sun but the earth actually rotates 366.25 times. The extra quarter day? Thats leap year!
Posted on: Sat, 15 Mar 2014 15:02:40 +0000
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