Baryonic acoustic oscillations

Scientists have found a way to study sound waves from the early universe to learn more about its history and contents.  Baryonic acoustic oscillations are sound waves from the early universe. Scientists have found a way to study these sound waves to learn more about the universe's history and contents. Shortly after the big bang, when the universe was hot and dense, regions with greater concentrations of light and matter had higher pressure than others. Acoustic waves--governed by the same laws...