Jason Rhodes wrote in message
...
"greywolf42" wrote in message
...
I belive you've gone circular, here. Without "dark matter" the big
bang's
current incarnation is dead. The "measurement" of distance used in
those
"lensing" studies assumes the big bang (pure doppler for the Hubble
constant). Hence your mass estimates are worthless for the purpose of
discriminating between dark matter and non-dark matter.

That is incorrect. The distance measurements were not inferred from
earlier
dark matter measurements, as your claim of circular reasoning would imply.

I neither claimed nor implied mass estimates were based on earlier 'dark
matter' measurements. They are based on 'big bang' DISTANCE measurements.

We are attempting to determine whether 'dark matter' exists, based on
lensing estimates. Dark matter is inferred whenever we compare two
disparate mass estimates. The first is when we calculate a mass of a galaxy
based on it's apparent visible stars (actually overall absolute
luminosity) -- which roughly 'counts' the number of visible stars and
(through theory) low-luminosity normal matter objects. This mass estimate
requires us to know the distance to the galaxy. Distances to galaxies
(those used in lensing papers) are determined SOLELY through the assumption
of the big bang -- that the measured redshift converts directly to a
distance.

The second mass estimate is based on the 'gravitational lensing' of a second
galaxy behind the first. The amount of lensing (angle of bend) is based on
two distances -- both determined solely by the big-bang theory (redshift IS
distance). The apparent bend of the light is then used to infer a mass of
the galaxy with the smaller redshift (presumed to be closer).

Now if the redshift - distance postulate is not universally correct under
all conditions, then (at the truly cosmic distances indicated) then not only
is the 'visible mass' estimate in error, the deflection angle (and the
'total mass' estimate) are both going to be incorrect.

The big bang relies upon dark matter to stay viable (otherwise omega is
nowhere near 1). Thus, "your mass estimates are worthless for the purpose
of discriminating between dark matter and non-dark matter."


However, if you fail to believe the preponderance of evidence pointing
toward a big bang universe, another completely independent measurement
using
an unrelated methodology that supports the currently accepted big bang
cosmology is unlikely to change your view.

I'm not aware of any preponderance of evidence for the big bang. Every time
there is a new observation at odds with the big bang (i.e. omega = .02
instead of 1, Hubble constant failure at high redshift), a "new" physical
phenomenon is invented to patch up the structure ('dark matter', 'dark
energy').

I'd be interested to see a demonstration of an alternative view that can
explain all the previous measurements as well as recent lensing
measurements.

[Mod. note: so would everyone else, but posters trying to meet this
challenge should bear in mind the s.p.r. and s.a.r. moderation
criteria -- mjh.]

How about one that predicted the hubble constant failure at high z, instead
of creating 'dark energy' as the latest epicycle (ad hoc)? Start with the
book "The Big Bang Never Happened", by Lerner. Then we can discuss the
measurements that you feel weigh more heavily on one side or the other.

greywolf42
ubi dubium ibi libertas