Cosmology Cosmology is the science of the Universe on its largest scales. It comprises the origins and evolution of this enormous entity, as well as the objects and structures therein. Life is a very complex and not well understood phenomenon that is present in the Universe, at least on the Earth. One of the deepest questions ever asked by humanity is whether life exists elsewhere in the Universe? Are we a very "rare" event, or is Life a common feature? How the Universe behaves In order to answer such questions, it is necessary to understand how the Universe behaves. This includes a proper description of the earliest development, which is now believed to have taken the form of a giant explosion, the Big Bang. It was followed by a subsequent, rapid expansion and many millions of years later, stars and galaxies formed. There is also little doubt that planets formed around many of these stars. The Universe apparently has a foam-like structure in which large voids are surrounded by thin walls made up of galaxies, mostly gathered in clusters. The largest of the clusters consists of many thousands of galaxies and each galaxy may contain many billions of stars. The elements were created at different times. While the lightest elements were produced during the Big Bang, the heavier ones were produced later in the stars. We, as living beings, consist of these elements and are therefore, in a sense, "true children of the stars". Recent research indicates that the Universe will continue to expand forever. However, new discoveries are often being made, for instance of dark matter and, very recently, of dark energy which may have implications we still do not fully understand. The Universe is very likely to be much more complex than we think now. A long way ahead It is the ultimate goal of cosmology to describe the complete story of the Universe, from the past to the present and also far into the future. Based on contemporary physics and supported by powerful instruments, we have made great progress in this study, but there is still a very long way to go and it is almost certain that there are great surprises ahead of us. In particular, we still do not have an answer to the question of whether we are alone in the Universe. However, on the basis of recent discoveries, for instance of many planetary systems around other stars and the presence of great amounts of organic molecules in space, most scientists now tend to believe that Life is also present in other places. More information A good briefing on this vast subject at an intermediate level - but not quite up-to-date - is available as "Cosmology - A Research Briefing" (US National Research Council, 1995).