Explain briefly the main physical processes that occurred in the era of recombination. If the recombination era took place at a redshift (1 + z) = 1100, calculate the temperature of the Universe at the era of recombination considering that the Cosmic Microwave Background (CMB) is a perfect black body and today has a temperature T = 2.725 K. State the peak wavelength at which the Universe emitted its radiation during the era of recombination, expressing your answer in nm.

Explain briefly the main physical processes that occurred in the era of recombination. If the recombination era took place at a redshift (1 + z) = 1100, calculate the temperature of the Universe at the era of recombination considering that the Cosmic Microwave Background (CMB) is a perfect black body and today has a temperature T = 2.725 K. State the peak wavelength at which the Universe emitted its radiation during the era of recombination, expressing your answer in nm.