If Earth makes one complete rotation on its axis every 23 hours and 56 minutes, how does day and night not being flipped on our clocks after six months? (6monthx30dayx4min/60=12hour)

Question

And why leap year happens once per 4 years only to address this?

In: 1081

Answer 1

>If Earth makes one complete rotation on its axis every 23 hours and 56 minutes, how does day and night not being flipped on our clocks after six months?

Because that’s a *sidereal* day, rather than a solar day.

Remember that the Earth also orbits around the Sun. Thus, if you define a day as the time it takes for the Sun to start at noon, and then get *back* to noon, this time will be a little longer than the sidereal day as the Earth has to spin a little bit further than 360 degrees for the Sun to be back in that same location relative to the sky.

The length of the solar day varies by as much as 51 seconds over the course of a year, but averages out to pretty damn close to 24 hours.