Due to several further specifications, first by Baade (1952) and thereafter by Sandage (1954, 1958), based on an essentially more detailed and larger set of observational data, the rescaled value of the Hubble parameter
at the present era, named the Hubble constant, gave for the age of the universe about 13.6 Gyr.
where the metric in the flat universe of FLRW is defined as d[s.sup.2] = d[t.sup.2] - [a.sup.2](t)[[summation].sub.i=1,2,3][(d[x.sup.i]).sup.2], a is the scale factor, and H = [??]/a is the Hubble parameter
. Moreover, the vector of the space tangent and metric are defined with the relations [e.sup.A.sub.[mu]] = diag(1, a, a, a) and [g.sub.[mu]v] = diag(1, -[a.sup.2], -[a.sup.2], -[a.sup.2]), respectively.
where G is Newton's constant, and H the Hubble parameter
. Note, with respect to , that we compute [[rho].sub.T] from (1) instead of the total dark fields density.
The universe's expansion rate, called the Hubble parameter
or Hubble constant, not only sets the time scale for cosmic expansion but also the scale for the universe's size and age.
You can also calculate the mass of the galaxy cluster and you can calculate what is called the Hubble parameter
, which tells us about the expansion of the universe.
The scale factor and Hubble parameter
therefore depend on the average energy density and not the local field dynamics.
If all parameters [[alpha].sub.2n] for n > 1 equal zero then the Hubble parameter
is described by the following formula:
and [H.sub.0] is the so called Hubble constant, the value of the Hubble parameter
H(t) at t = [T.sub.0], the current age of the Universe.
Before the space telescope, astronomers only knew that the Hubble parameter
-- a measure of the current expansion rate--was somewhere between 50 and 100 km/s per megaparsec (a parsec is about 3.26 light-years).
As a testimony to this, Hubble parameter
has been widely used to obtain explicit accelerating cosmological models in the framework of spatially homogeneous space-time .
To find the Hubble parameter
for the massive hadrons phase H(t > [a.sub.0]), we suggest the geometry transformation (5.3) in which the time [tau] : 0 [right arrow] [a.sub.0] for the quarks corresponds to the time t : 0 [right arrow] [infinity] for the massive hadrons phase.