The cosmic microwave background is a prediction of Big Bang theory. In the theory, the early universe was made up of a hot plasma of photons, electrons and baryons. The photons were constantly interacting with the plasma through Thomson scattering. As the universe expanded, adiabatic cooling caused the plasma to cool until it became favourable for electrons to combine with protons and form hydrogen atoms. This happened at around 3,000 K or when the universe was approximately 380,000 years old (z=1088). At this point, the photons did not scatter off of the now neutral atoms and began to travel freely through space. This process is called recombination or decoupling (referring to electrons combining with nuclei and to the decoupling of matter and radiation respectively).


That is the paragraph right?

It says:

The cosmic microwave background is a prediction of Big Bang theory. In the theory, the early universe was made up of a hot plasma of photons, electrons and baryons. The photons were constantly interacting with the plasma through Thomson scattering

That means there were photons before the 380000 year mark, but they were constantly interacting with the plasma until then, when it cooled enough to form hydrogen atoms.

correct me if I am wrong, I was just repeating it and i may be misunderstanding it completely