Learn to create a gravitational motion simulator in this coding tutorial focused on modeling the Sun-Earth system. Explore the Euler-Cromer method, visualize the Earth's size relative to the Sun, and gain insights into index tracking and error handling. Utilize VPython to build the simulation, with code available for download. Discover how to initialize objects, calculate gravitational forces, and implement conservation of angular momentum. Follow along as the tutorial guides you through the entire process, from setup to testing, ensuring a comprehensive understanding of simulating celestial mechanics.