The time interval from seeing the bright star Regulus rise over the eastern horizon until it rises again the following evening is
A) a solar day.
B) a sidereal day.
C) neither a solar day nor a sidereal day.
D) both a solar day and a sidereal day because these are the same for objects other than the Sun.

Question

Quizplus · Accepted Answer

A sidereal day is the time it takes for the Earth to rotate once on its axis relative to the stars, which is about 4 minutes shorter than a solar day. Since Regulus is a star, its rise from one day to the next is measured by a sidereal day, not a solar day.

The Time Interval from Seeing the Bright Star Regulus Rise