"Richard D. Saam" wrote:

As you can read he

https://en.wikipedia.org/wiki/Jeans_...eans.27_length

Jeans' length depends on T^(1/2) for constant mass density and
constant G. So, for high temperatures, the length is very big,
allowing only for big clouds to collaps, e.g. a proto-galactic cloud
to form a galaxy, whereas for low temperatures, also smaller clouds
can collaps, e.g. a proto-stellar cloud to a star.


What is the origin of these different
proto-galactic or proto-stellar cloud formation temperatures
in the context of the accepted
ubiquitous present CMBR 2.7 K temperature observation
that can be redshifted to any proto-galactic or proto-stellar cloud
era by (1+z)?

In today's universe, the average temperature is 2.7 K, which is low
enough for proto-stellar clouds to collaps. In the early universe,
the average temperature was higher, allowing only for proto-galactic
clouds to collaps. That's why star formation started some time
later than galaxy formation.