The Quantum Universe

AbstractCosmology was traditionally a field of wild speculations. During the last 25 years, however, the situation changed dramatically, since revolutionary progress in radio and sub-millimeter Astronomy made it possible to obtain direct "photographs'' of the Universe when it was just 300 thousand years old (while its estimated age is about 14 billion years). The comparison between these observations and theoretical predictions made more than 30 years ago provides strong evidence that quantum fluctuations, which are normally relevant at atomic and smaller scales, played a crucial role in providing the seeds for the large-scale structure that is currently observed in the Universe.