The Sidereal vs. Solar Day
23 hrs 56 min. versus 24 hrs 00 min.

Simon Shack

To put this problem into due perspective, let's see how the sidereal and solar day unfold in the below 3-frame sequence.

The following description is what is observed, in reality, from one day to the next :

In 23h 56m, an earthly observer will line up again with the same given star. At such a point and time, the Sun will already have moved Eastwards by approx. 4 minutes of RA. Four minutes later, we see the stars drifting by 4 min of RA Westwards.

Ergo, the entire amount of our daily, Westward stellar drift will appear (to an earthly observer) to occur in the last 4 minutes of earthly rotation. In other words, Earth might just as well be stationary while only rotating around its axis. Many astronomers in ancient times understandably believed this to be true. This wasn't because they were stupid, but because this is what matches careful and patient observation of the behavior of the heavens.

Of course, the TYCHOS model submits that Earth moves by a mere 38.4 km per day, which is hardly a noticeable amount of lateral displacement to the naked eye! Those 4 min. of RA are the consequence of Earth having rotated by 360