MCQ Detailed View

The planets in our solar system revolve around the Sun at different speeds. The speed of revolution mainly depends on how close a planet is to the Sun. Planets that are closer to the Sun experience a stronger gravitational pull, making them travel faster to stay in orbit. Planets that are farther away experience weaker gravitational force and move more slowly.

Among all planets, Mercury moves around the Sun at the highest speed. Mercury is the smallest and innermost planet of our solar system, orbiting the Sun at an average distance of 57.9 million kilometers. Because it is so close to the Sun, the gravitational attraction is stronger, and Mercury travels at an average orbital speed of about 47.87 kilometers per second. It takes only 88 Earth days for Mercury to complete one revolution around the Sun, which is the shortest orbital period of any planet.

In comparison:

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  Venus takes about 225 days to complete its orbit.

  
  


• 
  

  Earth takes 365 days.

  
  


• 
  

  Mars takes 687 days.

  
  


• 
  

  Jupiter, being farthest among the given options, moves at a much slower speed, taking about 12 Earth years to complete one orbit.

  
  

This difference in orbital speeds is explained by Kepler’s laws of planetary motion, which state that the closer a planet is to the Sun, the faster it must travel to counterbalance the Sun’s gravitational force.

Therefore, the correct answer is Mercury (Option D). This is a fundamental fact about the solar system that falls under Everyday Science knowledge, helping us understand the basic movement of planets around the Sun.