Which planet has the shortest day length?

Which planet has the shortest day length?

• A. Jupiter
• B. Mercury
• C. Mars
• D. Venus

Answer: (A)

Day length is how long a planet takes to spin once on its axis. Planets vary a lot in rotation speed, and the one that spins the fastest has the shortest day. Jupiter spins incredibly quickly, completing a rotation in about 9.9 hours, which is much shorter than the others listed. Mercury rotates slowly, taking about 58.6 Earth days to complete a turn; Venus rotates very slowly and in the opposite direction, taking around 243 Earth days; Mars completes a rotation in roughly 24.6 hours. Because Jupiter’s rotation is so fast, its day is the shortest among these planets.

Day length is how long a planet takes to spin once on its axis. Planets vary a lot in rotation speed, and the one that spins the fastest has the shortest day. Jupiter spins incredibly quickly, completing a rotation in about 9.9 hours, which is much shorter than the others listed. Mercury rotates slowly, taking about 58.6 Earth days to complete a turn; Venus rotates very slowly and in the opposite direction, taking around 243 Earth days; Mars completes a rotation in roughly 24.6 hours. Because Jupiter’s rotation is so fast, its day is the shortest among these planets.