"greywolf42" wrote in message
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"George Dishman" wrote in message
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"greywolf42" wrote in message
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"George Dishman" wrote in message
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Linearity is not assumed,

A false statement. It *IS* explicitly assumed. As demonstrated above
and in the references provided (which you snipped).

it is related to anisotropy
and homogeneity which again can be measured (though
not easily).

Meaning such have never been measured, merely assumed.

How much data do you need before an assumption becomes
a measured result?

At least one *direct* measurement in support,

By definition that is impossible since distant observations
are of the past. An indirect measurement is given below.

and *no* results contrary. The
supernova data are contrary to the linear assumption, however.

Sorry, that's simply not true. Learn the definition
of the Hubble Distance and you will see why.

They fit on
an exponential curve.

Perhaps, but it would be an exponential function of
time while the Hubble Law is linear with distance
at a given time. The two are not incompatible.

Peebles lists some of the evidence in "Principals of Physical
Cosmology".

But none of those address the specific issue under discussion. (If you
disagree, please provide the specifics. Not simply a vague allusion.)

They specifically address whether the universe is
homogenous and isotropic which leads to linearity
as a function of distance at a common time.

Take a look at
Figure 3.10, Condon's 1991 map of bright radio sources,
for example.

This does not address the issue of linearity of the Hubble graph.

It addresses the linearity of the Hubble Law, not
a plot of redshift versus _observable_ distance.

What you mean is that a departure from this linearity is
observed
at
higher redshift, which indicates an expanding universe.

It only indicates an expanding universe if your assumption is
true.
Which is not a given.

It indicates a time variation of the coefficient in
the law.

But only if your assumption is true. Which is the question.

You mean only if the evidence isn't misleading us ;-)

No, I mean if you can only think along the lines of one theory. The
evidence is the variation from linearity on the Hubble curve, shown by the
supernovae. *You* are ignoring the evidence.

No, I understand that there are two separate
dependencies which you are conflating. The
supernova data provides information about
the time dependency while evidence relating
to homogeneity relates to the spatial
dependence.

Perhaps "Hubble 'constant'" was a poor choice
of name (with hindsight).

The term itself is not the issue under discussion.

Like your conclusion that the distance - redshift relation might
be
linear? Unfortunately, this assumption will no longer
'stand up today.' The supernovae data blew it away.

Methinks thou trollst! You know better than that.

Not in the least. The nonlinear effect was predicted years ago.

Hubble Distance was defined years ago too, yet
you talk as if you had never heard of it. (The
link is my other reply if you really haven't.)

??? The "Hubble Distance" is not germaine to the assumption of linearity
of
the Hubble curve.

The Hubble Law, which is believed to be linear, is a
corelation with the Hubble Distance. How can you discuss
whether it is linear or not without first knowing how
that distance is defined?

George