Behind the powerful visible universe that envelops us at night, something different and much more impressive hides. Most astronomers today believe that ninety-five percent of the contents of the universe are invisible. Everything we observe in everyday life and in beautiful pictures from the Hubble telescope is probably only five percent of what is hidden in space. The rest is dark matter and energy - that part of reality that we have just begun to understand. So what are these dark invisible substances? And how can we be so sure of their existence? This book takes us on a journey through the universe, beyond the solar system and our native Milky Way. We will also immerse ourselves in the microscopic quantum world, take a closer look at gravity, light, the physical component of invisibility, exploding giant stars, colliding galactic lumps, ultra-sensitive detectors in deep mines, brilliant scientists and "spherical bastards."