Did you know that you would be a different age if you lived on Mars? It’s true! In this activity, you’ll learn about the different rotation and revolution periods of each of the planets and calculate your age respectively. Included is an astronomy history lesson and explanation of Kepler’s Laws of Orbital Motion. The activity has a calculator built into the web page, but the activity can be made more math intensive by using the given data to calculate the learner’s age by hand.