Does the Earth rotate once per day? Not really…
In 7th grade physics, we learn that the Earth takes 23 hours and 56 minutes for one rotation. Like me, have you wondered why our day is exactly 24 hours instead of this precise figure of 23hr 56min?. Did we just round it up? You may think it is negligible. Wouldn’t this shift of 4 minutes compound and cause a noticeable shift between the time shown on our clocks and the “actual time”. A simple calculation reveals that after one month there would be a shift of two hours, which means that 6 months later, there will be a shift of 12 hours and day becomes night and night becomes day! So, there must be more to this story which I set out to investigate. While watching an animation of the Earth revolving around the Sun, I noticed how the terminator (the line that separates day and night on the Earth) moves. Watching the terminator rotate once a year made me realize that this might be connected to the length of a day. As the Earth’s rotation and revolution are in the sam...