On Wednesday, 25 October 2017 23:34:51 UTC+2, Richard D. Saam wrote:
On 10/25/17 1:06 AM, Phillip Helbig (undress to reply) wrote:

"Dark matter" that we just doesn't seem able to see easily. But not
anything exotic. Just that: normal matter.

There are many arguments against this hypothesis, the main ones being
big-bang nucleosynthesis and CMB observations, which both agree that
most of the "missing matter" (i.e. "dark matter" as the term is normally
used) cannot be baryonic.

With what certainty should the 'cannot be' assertion be made. In
science, such absolute assertions are very rare. Current big-bang
nucleosynthesis calculations and CMB observation dark matter
correlations should not exclude a complementary dark matter contribution
by some other mechanism.

The whole issue is not dark matter because what is the definition?
The issue is the relation between baryonic versus nonbaryonic matter
in the universe and in our galaxy.

The Book the Big Bang by Joseph Silk defines the following events:
1) Big Bang
2) Particle Creation
3) Annihilation of proton-antiproton pairs
4) Annihilation of electron-positron pairs
5) Nucleosynthesis of helium and deuterium
6) (1 week) Radiation thermalizes prior to this epoch
7) (10 Years) Universe becomes matter dominated.
8) (300000 Y) Universe becomes transparant
9) (1-2 bil Y) Galaxy formation begins

My question is what is the percentage of baryonic matter in each
and which particular processes caused these changes. (roughly)

Suppose that all nonbaryonic matter in the universe (in outer space and
in our Galaxy Halo) are neutrino's when and how did they form?

An interesting article is:
https://arxiv.org/abs/astro-ph/9407006 1994
"Big-Bang Nucleosynthesis and the Baryon Density of the Universe"

See also: https://arxiv.org/abs/1505.01076
"Big Bang Nucleosynthesis: 2015"
In this article the word nonbaryonic is not mentioned.
The word dark matter is mentioned at the pages 3 and 16.

See also:
https://en.wikipedia.org/wiki/Big_Ba...esis#Deuterium
"This explanation is also consistent with calculations that show
that a universe made mostly of protons and neutrons would be far
more clumpy than is observed.[8]"
This raises the question how important is nonbaryonic matter
for the evolution of the Universe?

Nicolaas Vroom