HOW TO (DIS-)ASSEMBLE A PLANETARY SYSTEM (by turning a video game into an educational game).

Nowadays, computer simulations have reached amazing graphic results, providing awesome visual descriptions explaining the evolution of very complex physics phenomena, implementing the laws of Nature. Sometimes, without a scientific guide, it is difficult to distinguish between simulation and reality, but the usage of advanced and spectacular animations is a powerful way to convey both accurate scientific information and passion for science. According to this, we decided to develop an innovative scientific workshop based on an unconventional instrument: a video game. We used a commercial software called Universe Sandbox, a physics- based space simulator where astrophysics objects can be created, manipulated and followed in their evolution. We prepared a set of dynamic scenes to take the public through a virtual space journey whose main topics were planetary formation, orbits, habitable zones, types of stars, stellar explosions, and asteroid collisions. The interaction with the audience was at the heart of the experience: every question, suggestion, or idea was inserted in the simulation in real-time. This workshop was first proposed to the national festival of science in the city of Bergamo, in Italy, and we report our experience in this contribution. This activity is very easy to be replicated everywhere, both online and in-presence.