The cosmic microwave background radiation is the afterglow of the big bang: a tenuous signal, more than 13 billion years old, which carries the answers to many of the questions about the nature of our Universe. It was serendipitously discovered in 1964, and thoroughly investigated in the last four decades by a large number of experiments. Two Nobel Prizes in Physics have already been awarded for research on the cosmic background radiation: one in 1978 to Arno Penzias and Robert Wilson, who first discovered it, the other in 2006, to George Smoot and John Mather, for the results of the COBE satellite.

Most cosmological information is encoded in the cosmic background radiation by acoustic oscillations in the dense plasma that filled the primordial Universe: a "music" of the big bang, which cosmologists have long been trying to reconstruct and analyze, in order to distinguish different cosmological models, much like one can distinguish different musical instruments by their timbre and overtones. Only lately, this amazing cosmic sound has been unveiled by such experiments as BOOMERANG and MAXIMA and, more recently, by the WMAP satellite. This led to a giant leap in our understanding of the Universe, but the investigation is not ended yet.

The book focuses on how the exploration of the cosmic background radiation has shaped our picture of the Universe, leading even the non-specialized readers towards the frontier of cosmological research, helping them to understand, using a simple language and captivating metaphors, the mechanisms behind the Universe in which we live.

"This non-technical tour of the discovery and significance of the whispers of creation, the fossil radiation from the Big Bang, is a delight to read." Prof. Joe Silk, University of Oxford, a pioneering contributor to understanding the structure of the cosmic background radiation.

Autorentext

Amedeo Balbi is a researcher in cosmology at the Department of Physics of the University of Rome Tor Vergata. In the past, he worked at the University of California at Berkeley with George Smoot (Nobel Prize 2006 in Physics). Currently, he is involved in the preparation of ESA's forthcoming Planck satellite mission.

Zusammenfassung
Ever since its infancy, humankind has been seeking answers to some very basic and profound questions. Did the Universe begin? If it did, how old is it, and where did it come from? What is its shape? What is it made of? Fascinating myths and brilliant in- itions attempting to solve such enigmas can be found all through the history of human thought. Every culture has its own legends, itsownworldcreationtales,itsphilosophicalspeculations,itsre- gious beliefs. Modern science, however, cannot content itself with fanciful explanations, no matter how suggestive they are. No- days, our theories about the Universe, built upon rational ded- tion, have to survive the hard test of experiment and observation. Cosmology, the science which studies the origin and evo- tion of the Universe, had to overcome enormous dif?culties before it could achieve the same level of dignity as other physical dis- plines. At ?rst, it had no serious physical model and mathematical tools that could be used to address the complexity of the problems it had to face. Then, it suffered from a chronic lack of experim- tal data, which made it almost impossible to test the theoretical speculations. Given this situation, answering rigorously the many questions on the nature of the Universe seemed nothing more than a delusion. Today, however, things have changed. We live in the golden age of cosmology: an exciting moment, when, for the ?rst time, we are able to scienti?cally understand our Universe.

Inhalt
Prologue.- The framework (an introduction to the Big Bang model).- First light (an introduction to the cosmic background radiation - CMB).- Cosmic seeds (structure formation in the Universe and the CMB).- Music of the spheres (acoustic oscillations in the primordial Universe).- Finding harmony (the discovery of acoustic oscillations in the CMB power spectrum).- The undiscovered country (some future prospects).- Epilogue.