Galaxies without dark matter halos?

In article , greywolf42
writes:

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."

This is a valid point. Whenever discussing "alternative theories", one
has to take care that everything is calculated self-consistently. John
Barrow, for example, has often pointed this out. (He is a "mainstream
cosmologist" who has frequently investigated "alternative theories" such
as non-constant constants of nature etc.)

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').

You are making a big mistake here, confusing "The Big Bang" with some
statement about the value of Omega. It is easy to set up a straw man
(big bang implies Omega is near 1) then question the big bang when it is
found that Omega is not near one. But the big-bang theory (the universe
evolved from a dense, hot state, perhaps even a singularity) says
NOTHING about the value of Omega.

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.

If you read Lerner's book, read this as well:

http://www.astro.ucla.edu/~wright/lerner_errors.html

Phillip Helbig---remove CLOTHES to reply
wrote in message ...
You are making a big mistake here, confusing "The Big Bang" with some
statement about the value of Omega.

Nope. The value of omega was quite a serious problem for one of the earlier
incarnations of the big bang.

It is easy to set up a straw man
(big bang implies Omega is near 1) then question the big bang when it is
found that Omega is not near one.

I'm not setting up a straw man. I'm reporting one of the 'problems' of
earlier big bang theory. The early proponents of the big bang (which
doesn't include me) insisted that omega had to be near 1.0 to avoid some
nasty contradictions with observation.

But the big-bang theory (the universe
evolved from a dense, hot state, perhaps even a singularity) says
NOTHING about the value of Omega.

Today (with all the new epicycles) there may be 'no problem.' However, this
used to be called the 'flatness problem' in cosmological circles. It also
affected the 'anisotropy problem.' Alan Guth 'solved' the 'flatness
problem' by postulating 'inflation.' Which arbitrarily increased the size
of the universe for a brief period for no other reason but to avoid the
problem. But this meant that omega 'must' be 1.0. Hence, there 'must' be
dark matter -- since the observed matter only made omega equal to 0.02 or
0.03.

If you read Lerner's book, read this as well:

http://www.astro.ucla.edu/~wright/lerner_errors.html

I've read it. What's your point? Have you read TBBNH, or not?

Or would you care to begin by discussing Ned Wright's mudfest? (You'll need
TBBNH to do so, however.)

greywolf42
ubi dubim ibi libertas

[Mod. note: quoted text trimmed. Please do this yourself -- mjh]

Phillip Helbig---remove CLOTHES to reply
wrote in message ...
You are making a big mistake here, confusing "The Big Bang" with some
statement about the value of Omega.

Nope. The value of omega was quite a serious problem for one of the earlier
incarnations of the big bang.

It is easy to set up a straw man
(big bang implies Omega is near 1) then question the big bang when it is
found that Omega is not near one.

I'm not setting up a straw man. I'm reporting one of the 'problems' of
earlier big bang theory. The early proponents of the big bang (which
doesn't include me) insisted that omega had to be near 1.0 to avoid some
nasty contradictions with observation.

But the big-bang theory (the universe
evolved from a dense, hot state, perhaps even a singularity) says
NOTHING about the value of Omega.

Today (with all the new epicycles) there may be 'no problem.' However, this
used to be called the 'flatness problem' in cosmological circles. It also
affected the 'anisotropy problem.' Alan Guth 'solved' the 'flatness
problem' by postulating 'inflation.' Which arbitrarily increased the size
of the universe for a brief period for no other reason but to avoid the
problem. But this meant that omega 'must' be 1.0. Hence, there 'must' be
dark matter -- since the observed matter only made omega equal to 0.02 or
0.03.

If you read Lerner's book, read this as well:

http://www.astro.ucla.edu/~wright/lerner_errors.html

I've read it. What's your point? Have you read TBBNH, or not?

Or would you care to begin by discussing Ned Wright's mudfest? (You'll need
TBBNH to do so, however.)

greywolf42
ubi dubim ibi libertas

[Mod. note: quoted text trimmed. Please do this yourself -- mjh]

In article , greywolf42
writes:

Phillip Helbig---remove CLOTHES to reply
wrote in message ...
You are making a big mistake here, confusing "The Big Bang" with some
statement about the value of Omega.

Nope. The value of omega was quite a serious problem for one of the earlier
incarnations of the big bang.

"One of the earlier incarnations". What is an incarnation? Somebody's
pet theory du jour, intentionally confusingly deemed to be "part of the
big-bang theory" to lend it credibility.

I don't debate the fact that some people had great emotional problems
when their favourite value of Omega turned out to be wrong. But it is a
false dichotomy to say either one believes the big bang with the value
of Omega which is currently favourable, or, if that value turns out to
be wrong (in conflict with observations), then that brings down the
whole big bang theory. Simply not true. What's the point in playing
with words? Your line of argumentation is similar (but not identical)
to the question "Have you stopped beating your wife?"---the statement or
question itself makes invalid assumptions so that the other party is
prohibited from giving the truly correct answer.

I'm not setting up a straw man. I'm reporting one of the 'problems' of
earlier big bang theory. The early proponents of the big bang (which
doesn't include me) insisted that omega had to be near 1.0 to avoid some
nasty contradictions with observation.

OBSERVATIONS have never pointed to Omega = 1, at least not without very
large error bars or hidden assumptions (such as a flat universe) or
both. There WAS a lot of THEORETICAL PREJUDICE in favour of Omega = 1,
but it was just that, and never was essential to any version of the
big-bang theory. Sure, someone could come up with a theory of big bang
+ some value of Omega, but disproving that value of Omega disproves that
theory, not the big bang per se. Going back to the original, pure big
bang can hardly be called an epicycle.

Today (with all the new epicycles) there may be 'no problem.' However, this
used to be called the 'flatness problem' in cosmological circles. It also
affected the 'anisotropy problem.' Alan Guth 'solved' the 'flatness
problem' by postulating 'inflation.' Which arbitrarily increased the size
of the universe for a brief period for no other reason but to avoid the
problem. But this meant that omega 'must' be 1.0. Hence, there 'must' be
dark matter -- since the observed matter only made omega equal to 0.02 or
0.03.

First, you are confusing the big bang with inflation. The big bang is
practically a certainty. Whether or not inflation occurs is still open.
Also, if anything inflation favours a flat universe, hence only favours
Omega = 1 if one ASSUMES that there is no cosmological constant. Sure,
some people made this assumption and some didn't make this clear enough,
but the fact that this particular version has been ruled out says
nothing about the validity of the big bang per se.

In article , greywolf42
writes:

Phillip Helbig---remove CLOTHES to reply
wrote in message ...
You are making a big mistake here, confusing "The Big Bang" with some
statement about the value of Omega.

Nope. The value of omega was quite a serious problem for one of the earlier
incarnations of the big bang.

"One of the earlier incarnations". What is an incarnation? Somebody's
pet theory du jour, intentionally confusingly deemed to be "part of the
big-bang theory" to lend it credibility.

I don't debate the fact that some people had great emotional problems
when their favourite value of Omega turned out to be wrong. But it is a
false dichotomy to say either one believes the big bang with the value
of Omega which is currently favourable, or, if that value turns out to
be wrong (in conflict with observations), then that brings down the
whole big bang theory. Simply not true. What's the point in playing
with words? Your line of argumentation is similar (but not identical)
to the question "Have you stopped beating your wife?"---the statement or
question itself makes invalid assumptions so that the other party is
prohibited from giving the truly correct answer.

I'm not setting up a straw man. I'm reporting one of the 'problems' of
earlier big bang theory. The early proponents of the big bang (which
doesn't include me) insisted that omega had to be near 1.0 to avoid some
nasty contradictions with observation.

OBSERVATIONS have never pointed to Omega = 1, at least not without very
large error bars or hidden assumptions (such as a flat universe) or
both. There WAS a lot of THEORETICAL PREJUDICE in favour of Omega = 1,
but it was just that, and never was essential to any version of the
big-bang theory. Sure, someone could come up with a theory of big bang
+ some value of Omega, but disproving that value of Omega disproves that
theory, not the big bang per se. Going back to the original, pure big
bang can hardly be called an epicycle.

Today (with all the new epicycles) there may be 'no problem.' However, this
used to be called the 'flatness problem' in cosmological circles. It also
affected the 'anisotropy problem.' Alan Guth 'solved' the 'flatness
problem' by postulating 'inflation.' Which arbitrarily increased the size
of the universe for a brief period for no other reason but to avoid the
problem. But this meant that omega 'must' be 1.0. Hence, there 'must' be
dark matter -- since the observed matter only made omega equal to 0.02 or
0.03.

First, you are confusing the big bang with inflation. The big bang is
practically a certainty. Whether or not inflation occurs is still open.
Also, if anything inflation favours a flat universe, hence only favours
Omega = 1 if one ASSUMES that there is no cosmological constant. Sure,
some people made this assumption and some didn't make this clear enough,
but the fact that this particular version has been ruled out says
nothing about the validity of the big bang per se.

(Phillip Helbig---remove CLOTHES to reply) wrote in message ...
First, you are confusing the big bang with inflation. The big bang is
practically a certainty. Whether or not inflation occurs is still open.
Also, if anything inflation favours a flat universe, hence only favours
Omega = 1 if one ASSUMES that there is no cosmological constant. Sure,
some people made this assumption and some didn't make this clear enough,
but the fact that this particular version has been ruled out says
nothing about the validity of the big bang per se.

What does 'flatness' mean?

What is the difference between the shape of the universe - IE whether
it is infinite without boundary or finite without boundary - and
whether it's closed, open, or flat, which has to do with it being on
the boundary of open or closed, and where open and closed, and flat,
have to do with the expansion of the universe?

I take it that these questions are related, but that their answers are
not bound to one another.

[Mod. note: quoted text trimmed -- mjh.]

(Phillip Helbig---remove CLOTHES to reply) wrote in message ...
First, you are confusing the big bang with inflation. The big bang is
practically a certainty. Whether or not inflation occurs is still open.
Also, if anything inflation favours a flat universe, hence only favours
Omega = 1 if one ASSUMES that there is no cosmological constant. Sure,
some people made this assumption and some didn't make this clear enough,
but the fact that this particular version has been ruled out says
nothing about the validity of the big bang per se.

What does 'flatness' mean?

What is the difference between the shape of the universe - IE whether
it is infinite without boundary or finite without boundary - and
whether it's closed, open, or flat, which has to do with it being on
the boundary of open or closed, and where open and closed, and flat,
have to do with the expansion of the universe?

I take it that these questions are related, but that their answers are
not bound to one another.

[Mod. note: quoted text trimmed -- mjh.]

In article ,
(Starblade Darksquall) writes:

What does 'flatness' mean?

That the geometry of space is familiar Euclidean geometry, as opposed to
being positively or negatively curved. The analogues in two dimensions
are a plane, the surface of a sphere and the surface of a saddle.
Positive curvature implies a closed universe, negative or zero curvature
(flatness) an open universe. "Open" and "closed" here refer to SPACE.

Sometimes "open" is used to mean a universe which expands forever and
"closed" is used to mean that it will collapse in the future. One could
think of these terms as being temporal rather than spatial in this case,
but I think it is best to use the terms to refer to the spatial
properties and use other terms---"expands forever", "will collapse
again" to refer to the history of the expansion (or contraction) of the
universe. Better yet, don't use the terms at all, but use "positive
curvature" and "negative curvature" to classify the spatial aspects.

(Note for the experts: I am assuming a simple topology here.)

What is the difference between the shape of the universe - IE whether
it is infinite without boundary or finite without boundary - and
whether it's closed, open, or flat, which has to do with it being on
the boundary of open or closed, and where open and closed, and flat,
have to do with the expansion of the universe?

I take it that these questions are related, but that their answers are
not bound to one another.

In general, the shape of the universe and its expansion history are
independent in the sense that all combinations are possible. In
particular, the values of Omega and lambda determine both.

Let me plug my own version of explaining this:

http://www.astro.multivax.de:8000/he...ngsiz_guide.ps

or, to save bandwidth,

http://www.astro.multivax.de:8000/he...iz_guide.ps-gz

Some confusion has arisen because, as one can see from the diagram on
page 3 of the above reference, in the case of a vanishing cosmological
constant, positive curvature implies collapse, negative implies
expansion forever and flatness implies that the expansion speed
asymptotically approaches zero.

An absolute must-see web page for anyone interested in this kind of
stuff is

http://www.jb.man.ac.uk/~jpl/cosmo/f....html#solution

In article ,
(Starblade Darksquall) writes:

What does 'flatness' mean?

That the geometry of space is familiar Euclidean geometry, as opposed to
being positively or negatively curved. The analogues in two dimensions
are a plane, the surface of a sphere and the surface of a saddle.
Positive curvature implies a closed universe, negative or zero curvature
(flatness) an open universe. "Open" and "closed" here refer to SPACE.

Sometimes "open" is used to mean a universe which expands forever and
"closed" is used to mean that it will collapse in the future. One could
think of these terms as being temporal rather than spatial in this case,
but I think it is best to use the terms to refer to the spatial
properties and use other terms---"expands forever", "will collapse
again" to refer to the history of the expansion (or contraction) of the
universe. Better yet, don't use the terms at all, but use "positive
curvature" and "negative curvature" to classify the spatial aspects.

(Note for the experts: I am assuming a simple topology here.)

What is the difference between the shape of the universe - IE whether
it is infinite without boundary or finite without boundary - and
whether it's closed, open, or flat, which has to do with it being on
the boundary of open or closed, and where open and closed, and flat,
have to do with the expansion of the universe?

I take it that these questions are related, but that their answers are
not bound to one another.

In general, the shape of the universe and its expansion history are
independent in the sense that all combinations are possible. In
particular, the values of Omega and lambda determine both.

Let me plug my own version of explaining this:

http://www.astro.multivax.de:8000/he...ngsiz_guide.ps

or, to save bandwidth,

http://www.astro.multivax.de:8000/he...iz_guide.ps-gz

Some confusion has arisen because, as one can see from the diagram on
page 3 of the above reference, in the case of a vanishing cosmological
constant, positive curvature implies collapse, negative implies
expansion forever and flatness implies that the expansion speed
asymptotically approaches zero.

An absolute must-see web page for anyone interested in this kind of
stuff is

http://www.jb.man.ac.uk/~jpl/cosmo/f....html#solution

In article ,
(Jeffery) writes:

Omega = 1, as pedicted by inflation. Omega_m ~ 0.3, Omega_Lambda ~
0.7, and Omega_r ~ 10^-6 which is negligible, sop

Omega = Omega_m + Omega_Lambda = 0.3 + 0.7 = 1

Inflation predicts Omega = 1, which is also what we observe from the
CMB anisotropy. We observe Omega_m ~ 0.3 from gravitation lensing. We
observe Omega_Lambda ~ 0.7 from Supernovae Ia data, so everything is
consistent.

Jeffery Winkler

[Mod.note -- I suspect Phillip was referring to Omega_matter, in this
context -- mjh]

Indeed. My Omega and lambda are some folks' Omega_m and Omega_lambda.
Why do I prefer my terminology? In general, Omega and lambda are
time-dependent, and a subscript of 0 is used to indicate the present
value. Thus, with the other terminology, one needs double subscripts
etc.

Nevertheless, there really were "serious cosmologists" claiming that
inflation predicted Omega_m to be 1, just a few years ago. I suspect
they knew that the real prediction was flatness, but were betting that
the cosmological constant was zero so that the universe would be simple
enough for them. :-)