Among the several risks to which the terrestrial life is subject, there is a remote possibility of collision with minor astronomical bodies such as comets and asteroids, which can potentially cause consequences ranging from minor damages to large cataclysms with reflections for the whole Earth. The frequency of the collisions is smaller whenever the external bodies are bigger and more massive. It is possible to conduct simu-lations taking into account these factors and the velocities and angles of the collisions to estimate their prob-abilities, the consequences for our planet and the frequency of such events. The results of the simulations are presented graphically to facilitate the final analysis. Finally, we point out that there are several research cen-ters in the world working in the surveillance of the sky to identify possible “aggressive” bodies and evaluate the actual risks for the planet.