Looking at the numbers above, you'll immediately notice that you are different ages on the different planets. This brings up the question of how we define the time intervals we measure. What is a day? What is a year?The earth is in motion. Actually, several different motions all at once. There are two that specifically interest us. First, the earth rotates on it's axis, like a spinning top. Second, the earth revolves around the sun, like a tetherball at the end of a string going around the center pole.
The top-like rotation of the earth on its axis is how we define the day. The time it takes the earth to rotate from noon until the next noon we define as one day. We further divide this period of time into 24 hours, each of which is divided into 60 minutes, each of which is broken into 60 seconds. There are no rules that govern the rotation rates of the planets, it all depends on how much "spin" was in the original material that went into forming each one. Giant Jupiter has lots of spin, turning once on its axis every 10 hours, while Venus takes 243 days to spin once.
The revolution of the earth around the sun is how we define the year. A year is the time it takes the earth to make one revolution - a little over 365 days.
We all learn in grade school that the planets move at differing rates around the sun. While earth takes 365 days to make one circuit, the closest planet, Mercury, takes only 88 days. Poor, ponderous, and distant Pluto takes a whopping 248 years for one revolution. Below is a table with the rotation rates and revolution rates of all the planets. Check more