Era of recombination - temperature variant

[thomas49th]

Homework Statement

When radiatio was first emmited 300,000 years after the big bang during the so-called era of recombination, it was in the visible region of the spectrum. What does this data tell scientist about the temperature variant of the early universe

Homework Equations

The Attempt at a Solution

well aparently the temperature remained pretty much constant, but how do you tell that?

 

[malawi_glenn]

why is the temperature constant? The temperature decreased!