Using the Euler cromer method, we will investigate the movement of solar entities in orbit. First, we will write a program that numerically finds the position and velocity of the earth as it orbits the sun. Second, we will write a program that numerically finds position and velocity of the moon as it orbits the earth as the earth orbits the sun. Third, we will write a program that numerically finds the position and velocity of a large star such as the sun as a massive planet orbits it, or rather as they orbit and affect each other. To calculate these movements we will use basic equations of motion and Kepler’s laws.