Cooray et al - A Possible Solution to IR/X-ray Correlation?

In article , "Richard D. Saam"
writes:

I've said many times that if one reads just one paper in cosmology, this
should be it.

and available at:
NASA astrophysics data system
http://adsabs.harvard.edu/abs/1966MNRAS.132..379S

Underlying these many Friedman Equation solutions
is the assumption that universe mass Mu is constant with time
such that constant Mu = rho_m*R^3.
Having universe mass Mu not constant with time
may complicate the solution
but does not in itself negate the Friedman Equations
or supporting Einstein theory.

This is not really an assumption but follows from basic conservation
laws. If mass is converted to radiation, then this changes the
expansion behaviour, but this is important only in the early universe
(at least for models which even broadly agree with current
observations).

On 11/6/12 2:32 PM, Phillip Helbig---undress to reply wrote:
In article , "Richard D. Saam"
writes:

I've said many times that if one reads just one paper in cosmology, this
should be it.

and available at:
NASA astrophysics data system
http://adsabs.harvard.edu/abs/1966MNRAS.132..379S

Underlying these many Friedman Equation solutions
is the assumption that universe mass Mu is constant with time
such that constant Mu = rho_m*R^3.
Having universe mass Mu not constant with time
may complicate the solution
but does not in itself negate the Friedman Equations
or supporting Einstein theory.

This is not really an assumption but follows from basic conservation
laws. If mass is converted to radiation, then this changes the
expansion behaviour, but this is important only in the early universe
(at least for models which even broadly agree with current
observations).

I thought logic dictated radiation came first
repeating from befo
let the radiation CMB density component be
sigma*Tb^4*4/c^3 = rho_b = 4.67E-34 g/cc (present value at Tb = 2.73K)
and mass density component
(3/8pi)*H^2/G = rho_c = 9.57E-30 g/cc (present value)

rho_b scales as (1+z)^4
and
rho_c scales as (1+z)^3

Looking back,
the mass dominated universe transitions
into radiation dominated universe at:
Tb = 37,200 K z= 13,600 age = 8,600 years
rho_b = rho_c = 1.62E-17 g/cc

From this point back
the universe extrapolates to 100 percent radiation.

These discussions are in terms of densities and relative abundances.
Until universe volumetrics are known,
absolute universe masses remain unknown.

Richard D. Saam

In article , "Richard D. Saam"
writes:

This is not really an assumption but follows from basic conservation
laws. If mass is converted to radiation, then this changes the
expansion behaviour, but this is important only in the early universe
(at least for models which even broadly agree with current
observations).

I thought logic dictated radiation came first
repeating from befo

Well, yes; I was thinking of going back in time.

the mass dominated universe transitions
into radiation dominated universe at:
Tb = 37,200 K z= 13,600 age = 8,600 years
rho_b = rho_c = 1.62E-17 g/cc

From this point back
the universe extrapolates to 100 percent radiation.

Yes.

These discussions are in terms of densities and relative abundances.
Until universe volumetrics are known,
absolute universe masses remain unknown.

Right; we don't even know if the universe is finite or not.

On 11/6/12 2:32 PM, Phillip Helbig---undress to reply wrote:
In article , "Richard D. Saam"
writes:

I've said many times that if one reads just one paper in cosmology, this
should be it.

and available at:
NASA astrophysics data system
http://adsabs.harvard.edu/abs/1966MNRAS.132..379S

Underlying these many Friedman Equation solutions
is the assumption that universe mass Mu is constant with time
such that constant Mu = rho_m*R^3.
Having universe mass Mu not constant with time
may complicate the solution
but does not in itself negate the Friedman Equations
or supporting Einstein theory.

This is not really an assumption but follows from basic conservation
laws. If mass is converted to radiation, then this changes the
expansion behaviour, but this is important only in the early universe
(at least for models which even broadly agree with current
observations).


That appears to be the basic premise:
that something happened at the early universe
that thermodynamically proceeds to the current state.
Robertson, H. P.,
"Relativistic Cosmology," Rev. Mod. Phys., 5, 62-90 (1933)
Available at:
http://link.springer.com/article/10....714-012-1401-0
Robertson gives all the options flowing from Einstein's theory
with a very good timeline of the preceding logic
VI. Bibliography
Current observations (including dark matter and dark energy)
indicate a need for more emphasis
related to ongoing synthetic processes
the nature of which is problematic.