> > Now we're saying the earth's actual rotation is four minutes shy of 24 hours?
> >
> > My head is starting to spin. Somebody fix me.
>
> "The Earth rotates once in a few minutes under a day (23 hours 56 minutes 04. 09053 seconds). This is called the sidereal period (which means the period relative to stars). The sidereal period is not exactly equal to a day because by the time the Earth has rotated once, it has also moved a little in its orbit around the Sun, so it has to keep rotating for about another 4 minutes before the Sun seems to be back in the same place in the sky that it was in exactly a day before."
>
> -FP

Also, from another section at nasa.gov:

"The solar day of 24 hours measures the time between the moment of sunrise and the same moment the next day. During this time, the Sun moves along the sky by a short distance so that in 365.24 days it completes a full traverse along the ecliptic. This motion is at the rate called the mean solar day, but because the motion of the Sun is not at constant speed across the sky as the Earth moves in an elliptical path, the Sun gets ahead and behind the mean solar day by up to 10 minutes or so, and this is called the 'Equation of Time'. Anyway, the point is that your clocks tick off the passage of the mean solar 24-hour day, and the missing 4 minutes aren't really missing at all, they just show up in the changing ebb and flow of the seasonal rising and setting of the sun and length of daylight. "

-Faux "finder of things, fixer of Sam" Pas