Rekombinationaika

Rekombinationaika refers to the period in the early universe, approximately 380,000 years after the Big Bang, when electrons and protons combined to form neutral hydrogen atoms. Prior to this epoch, the universe was a hot, dense plasma where photons were constantly scattered by free charged particles, making it opaque. As the universe expanded and cooled, the kinetic energy of these particles decreased to a point where the electromagnetic attraction between protons and electrons became strong enough to overcome their thermal motion. This process, known as recombination, led to the formation of neutral atoms.

The formation of neutral atoms had profound consequences for the universe. It drastically reduced the scattering of photons, allowing them to travel freely for the first time. These freely streaming photons are what we observe today as the Cosmic Microwave Background (CMB) radiation. The CMB is a snapshot of the universe at the time of recombination and provides invaluable information about its early conditions, composition, and evolution. The temperature of the universe at the time of recombination is estimated to have been around 3000 Kelvin. This event is a crucial milestone in cosmological history, marking the transition from an opaque plasma to a transparent, neutral universe that eventually allowed for the formation of stars and galaxies.