The Complete Book of Questions and Answers Earth and Space Huge though it is, our world is tiny in astronomical terms, just one of the many billions of planets that are believed to exist throughout the universe. Until recently, there was no proof that there were any other planets outside our own solar system, but now satellite technology has shown that there are planets close to several nearby stars, and almost certainly, planets orbiting most of the countless other stars in the vast expanse of our universe. The structure of the solar system govern our life, because it is the means by which we measure time and experience the changing seasons. The movement of the Earth and the moon control day and night, together with the ocean tides. These nearby events are well understood, but the distant parts of the universe are still a mystery, debated by scientists and mathematicians. Strange signals from space are received by radio telescopes, light is sucked into black holes, and time itself might be distorted by high-speed space travel. Back on Earth, things are better understood. We can see and experience the forces that change the shaped of our world and can use them to generate power by wind, waves, and even by radioactivity. We understand the seasons, and this tells us when to plant crops. We are also beginning to understand how catastrophes like earthquakes, volcanic eruptions, droughts, and floods occur, and can take measures to reduce their effects, The activities of mankind have shaped our world and have sometimes been the cause of these catastrophes. The Universe