Baryon acoustic oscillations

Baryonic acoustic oscillations are density waves, who trained in the early universe by the interplay of gravitation and radiation pressure. Their effects are observable today in Anisotropiespektrum the cosmic background radiation and in the distribution of galaxies. Your exact measurement plays an important role in modern cosmology.

Details

According to the current theory of matter consists of dark matter and baryonic matter out. After inflation, the matter is not distributed perfectly homogeneous, there are initial fluctuations. Due to the gravitational baryonic matter is drawn to areas with higher density of dark matter. The density of baryons to photons increases and the pressure increases. This urges the baryonic matter apart again, thus causing a decrease in the baryon density. Through this interplay of attraction and repulsion by gravity through the photon pressure, the baryonic matter begins to oscillate. This mechanism breaks down in the decoupling of radiation and matter about 380,000 years after the Big Bang. The baryonic matter subject from now on only the gravity. "Save " photons but the information on the density of the baryons at source at the time of the decoupling in terms of temperature.