Question

The earth completes one rotation from west to east on its axis in ___________.

• A. 23 hours, 56 minutes, 4.09 seconds.
• B. 23 hours, 59 minutes, 4.09 seconds
• C. 23 hours, 58 minutes, 4.09 seconds
• D. 23 hours, 57 minutes, 4.09 seconds

Answer 1

Answer: (A)

23 hours, 56 minutes, 4.09 seconds.

• As we all know, it takes exactly 24 hours for the Sun to return to the same spot in the sky, which would seem obvious.
  
• 24 hours is what we think of as being a complete day, and the time it takes to transition from day to night and back again.
  
• But in truth, it actually takes the Earth 23 hours, 56 minutes, and 4.09 seconds to turn rotate once on its axis compared to the background stars.
  
• Why the difference? Well, that would be because the Earth is orbiting around the Sun, completing one orbit in just over 365 days. If you divide 24 hours by 365 days, you’ll see that you’re left with about 4 minutes per day.
  
• In other words, the Earth rotates on its axis, but it’s also orbiting around the Sun, so the Sun’s position in the sky catches up by 4 minutes each day.