How many sidereal days are there in a year?

A sidereal day is the time it takes for the Earth to rotate once on its axis relative to the fixed stars, which is approximately 23 hours, 56 minutes, and 4 seconds. This means that there are about 366.24 sidereal days in the time it takes for the Earth to complete one orbit around the Sun, which is one year.

In a standard year, the Earth completes this orbit while also rotating on its axis. As a result, there are about 366.24 sidereal days in a year. When rounding to the nearest whole number, this represents 366 full rotations.

The choice indicating 366 1/4 sidereal days accurately reflects this understanding. It’s significant to note that other options, such as 365 1/4 or 364, do not represent the true number of sidereal days in a year, as they underestimate the total rotations relative to the stars.