General Navigation USCG Question #1744 (Set 55)

A sidereal day is approximately how much shorter than a solar day?

Official USCG Answer & Rule Citation

Correct Answer: Option A — 4 minutes

A sidereal day is shorter than a solar day by approximately 3 minutes and 56 seconds, commonly rounded to 4 minutes. As detailed in Bowditch, this discrepancy arises because Earth must rotate slightly more than 360 degrees to bring the Sun back to the same meridian daily.

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