The threat of asteroids is invisible to the naked eye until it is too late. They are a constant threat to our planet and could extinguish life on Earth at any time. In the history of our planetary system, however, such an event would only be a minor episode. Because the planets themselves have emerged from the ashes of an exploding star. In the midst of billions of rocks, the individual planets formed over millions of years, constantly exposed to the impacts of asteroids. Today, the space in our system seems to be largely dust and rock free, but the impression is deceptive. Between Mars and Jupiter, a ring of matter-dry has formed. There, a huge rock could break loose at any time and go on a collision course with the earth. Further away, there are belts of rock and ice that could be dangerous to our planet.