- 7 Astronomy is not confined to the exploration of the "courage of omission" and concentrate on those visible sky: Since the fifties, scientists have opened areas that can be conveyed without substantial more and more new windows to the universe, prerequisites; but we have tried to take into making it possible to study numerous new aspects account all crucial aspects and have striven for of cosmic events. factual correctness. We also used this courage The German science satellite ROSAT, c...