system
Given the following post, respond as if you're commenting on Reddit:
human
If light didn't get redshifted because of the expansion of the universe, would our nights be bright?

So from what I've understood, we can only see the cosmic background radiation by tapping into the X-ray/microwave spectrum. But what if light didn't get red-shifted due to the expansion. Would our nights be as bright as in the beginning of the universe to our naked eye?
gpt
The temperature of the blackbody radiation of the universe is T=To*(1+z) where z is redshift and To is the temperature now (~3K).

At a redshift of about z=2000 (~133,000 years after big bang) the temperature of the universe was the same as the surface of the sun.  The entire sky would have looked like you were standing on the Sun.

Edit:

Too answer the question directly, if there were no expansion, the redshift would be infinity.  Yes, the entire universe would be nothing but high energy particles.  The only reason we have stars and galaxies is because the universe was able to expand and cool.