On 10/26/17 2:36 AM, Phillip Helbig (undress to reply) wrote:
In article , "Richard D.
Saam" writes:

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.

Relatively high certainty.

Current big-bang
nucleosynthesis calculations and CMB observation dark matter
correlations should not exclude a complementary dark matter contribution
by some other mechanism.

They exclude, to a high degree of certainty, most of the missing matter
being baryonic. Yes, that might be wrong, but one needs to show that it
is wrong; one can't claim that since there is no absolute certainty, we
might as well assume that an alternative claim---with zero evidence to
support it---is just as good.

It is not a matter of being wrong but incomplete.
For reference, CMB blackbody parameters
with associated redshifts(1+z)^n a

Temperature 2.729*(1+z)^1 kelvin
Frequency 1.60x10^11*(1+z)^1 Hz
Wave Length .106*(1+z)^-1 cm
Mass Density 4.67x10^-34*(1+z)^4 g/cm^3
Energy Density 4.20x10^-13*(1+z)^4 erg/cm^3
Photon Density 412*(1+z)^3 #/cm^3

Small variation of these numbers
as indicators of Dark Matter
represent a small segment of the universe parameter space.
Larger frequencies(energies) have been studied for the WIMP searches
but lower frequencies(down to the microHz level)
have not been adequately searched
(mostly due to instrumentation measurement inadequacies)
for other dark matter contributors.

As for nucleosynthesis mechanisms,
there is an ongoing LHC study of nuclear dynamics
simulating The Big Bang that may bring more certainty
in resolving incompleteness.


[[Mod. note -- Experiments at Brookhaven's RHIC (Relativistic Heavy
Ion Collider) are also relevant here. -- jt]]