Approximately how long does Earth take to rotate once about its axis?

Approximately how long does Earth take to rotate once about its axis?

• A. One day
• B. One year
• C. One hour
• D. One week

Answer: (A)

Earth spins on its axis and completes one full rotation in about 24 hours, which is what we call a day. If you measure against distant stars, the rotation is a bit shorter—about 23 hours and 56 minutes—known as a sidereal day; the 24-hour solar day we use reflects the Sun’s apparent movement due to both rotation and orbit. The year is the time it takes Earth to orbit the Sun, while an hour or a week are not the length of a full rotation.

Earth spins on its axis and completes one full rotation in about 24 hours, which is what we call a day. If you measure against distant stars, the rotation is a bit shorter—about 23 hours and 56 minutes—known as a sidereal day; the 24-hour solar day we use reflects the Sun’s apparent movement due to both rotation and orbit. The year is the time it takes Earth to orbit the Sun, while an hour or a week are not the length of a full rotation.