Your Age on Other Planets

In science class, you learned that the farther a planet is from the Sun, the longer its period of revolution. Every time Earth makes a trip around the Sun, you become one year older. How old would you be now if you lived on the other planets? Try this activity with your family members to find out!


Picture of Earth orbiting the Sun.


  1. Calculate your age in Earth days. (your age in years times 365 days)
  2. Divide your age in Earth days by the number of days in another planet's revolution period, or “year.”
  3. The answer is your “new” age!
Planet Number of Days in Year Age
Mercury 88 days  
Venus 225 days  
Earth 365 days  
Mars 687 days  
Jupiter 4,329 days  
Saturn 10,752 days  
Uranus 30,660 days  
Neptune 60,152 days  
Pluto 90,410 days  


On which planet would you be oldest? Why? Do you notice any patterns in the numbers on your chart? What is the pattern? What do you think is the reason for the pattern?