To facilitate the process of teaching and learning in physics, through the use of computers, avoiding to learn numerous programming languages, several software was developed, among them Modellus. The nuances in its use focus on processes that aim at activities that basically require the concepts of Science, Mathematics and basic computer studies. This article aims to present a computational model developed for use in Software Modellus and to assist in teaching the Earth thematic as a cosmic body. This approach to Earth means to study it through its form, its gravitational field, its movements and the astronomical phenomena arising from these movements and the configuration of the Sun-Earth-Moon system, that is, its interaction with other cosmic stars. Initially, the method of construction by means of an algorithm is presented, and also, how its implementation in the software should occur. The respective interactions with the functions in Modellus are also indicated. Finally, the computational model of the Sun-Earth-Moon system is presented in an executable form, aiding the learning process of the Earth Thematic as a cosmic body.