Star age Measurements

[David Levy]

I would like to get your advice with regards to the Star age
Measurements.

This is critical element for any theory. This is a key element for
confirming the Big bang theory. Therefore, I was quite surprise to find
that this key measurement is actually based on the Big Bang theory.

Based on Wiki it is stated:

"The metallicity of an astronomical object may provide an indication of
its age. When the universe first formed, according to the Big Bang
theory, it consisted almost entirely of hydrogen which, through
primordial nucleosynthesis, created a sizeable proportion of helium and
only trace amounts of lithium and beryllium and no heavier elements.
Therefore, older stars have lower metallicities than younger stars such
as our Sun."

So the science is measuring the star age based on the fundamental Idea
of the Big bang.
With the results of the star age they are coming back and reconfirm the
Big bang theory.

This might be radicals and contradicts a basic common sense.
I assume that without the big bang theory, the Science could develop
some other method for Star age measurements.

Please advice.




--
David Levy

[Mike Dworetsky]

David Levy wrote:
> I would like to get your advice with regards to the Star age
> Measurements.
>
> This is critical element for any theory. This is a key element for
> confirming the Big bang theory. Therefore, I was quite surprise to
> find that this key measurement is actually based on the Big Bang
> theory.
>
> Based on Wiki it is stated:
>
> "The metallicity of an astronomical object may provide an indication
> of its age. When the universe first formed, according to the Big Bang
> theory, it consisted almost entirely of hydrogen which, through
> primordial nucleosynthesis, created a sizeable proportion of helium
> and only trace amounts of lithium and beryllium and no heavier
> elements. Therefore, older stars have lower metallicities than
> younger stars such as our Sun."
>
> So the science is measuring the star age based on the fundamental Idea
> of the Big bang.
> With the results of the star age they are coming back and reconfirm
> the Big bang theory.

You make it sound like a circular argument, but it isn't. Star ages were
established by analysis of the HR diagrams of star clusters. It was found
in the 1950s that globular star clusters, for example, were of order 10
billion years old. By then the age of the Earth had been fairly well
established at about 4-4.5 billion years. The problem at the time was that
Hubble expansion was indicating a cosmological age of around 5-8 billion
years. It was far more difficult to make meaningful estimates of distances
of far away galaxies back then so it was accepted that the figures for
cosmological age were probably wrong, but it turned out that fixing this
would take many years of serious effort and require new technology.

>
> This might be radicals and contradicts a basic common sense.
> I assume that without the big bang theory, the Science could develop
> some other method for Star age measurements.

Indeed, the theory of stellar evolution came up with the tools during the
1950s and these were greatly improved from around 1960 with the advent of
large-enough amounts of computer power.

>
> Please advice.

--
Mike Dworetsky

(Remove pants sp*mbl*ck to reply)

[Yousuf Khan]

On 17/05/2013 6:44 PM, David Levy wrote:
> I would like to get your advice with regards to the Star age
> Measurements.
>
> This is critical element for any theory. This is a key element for
> confirming the Big bang theory. Therefore, I was quite surprise to find
> that this key measurement is actually based on the Big Bang theory.
>
> Based on Wiki it is stated:
>
> "The metallicity of an astronomical object may provide an indication of
> its age. When the universe first formed, according to the Big Bang
> theory, it consisted almost entirely of hydrogen which, through
> primordial nucleosynthesis, created a sizeable proportion of helium and
> only trace amounts of lithium and beryllium and no heavier elements.
> Therefore, older stars have lower metallicities than younger stars such
> as our Sun."
>
> So the science is measuring the star age based on the fundamental Idea
> of the Big bang.
> With the results of the star age they are coming back and reconfirm the
> Big bang theory.

This only works for roughly comparing & categorizing really old stars
(mainly first and second generation) vs. modern ones (third generation).
The earliest generation stars were hydrogen monsters, converting a lot
of hydrogen into heavier stuff, and blowing up really quickly. They were
the earliest supernovas, and they created and polluted the galaxies with
all of the heavy elements above helium all of the way upto uranium.
They're all dead by now.

All later generations of stars had little bits of the first generation
stars' grit embedded inside them. The second generation right after the
first generation had some of this grit in them, but not much. There
should still be a few second generation stars left in the galaxy. Then
the third generation had even more of this grit than the second
generation. However, this is not a linear relationship, you don't have
successive generations of stars getting grittier and grittier. In fact,
all current generation stars are considered 3rd generation, whether they
were born 5 billion years ago, or yesterday. That's because 3rd gen
stars are mostly indistinguishable in terms of metallicity. The galaxies
aren't getting more metallic, so you need other methods to distinguish
one 3rd generation star from another.

> This might be radicals and contradicts a basic common sense.
> I assume that without the big bang theory, the Science could develop
> some other method for Star age measurements.

They have, metallicity is hardly the only way to determine the age of a
star, they also use its mass, its temperature, brightness, etc. As I
said, all stars are 3rd generation now, so metallicity is not the only
way to determine a star's age, nor even the best way.

For example, we know that the Sun is 4.5 Gyears old. It's a yellow star
in the main sequence of a certain mass, and a certain temperature and
brightness. When it was first born, it was still yellow, but it produced
about 30% less heat than it does now, and also a little bit dimmer. It
grows in heat roughly 10% per billion years, while in the main sequence.
It'll be at its brightest of the main sequence in about another 5
billion years, when it will be about 50% brighter than today, just
before it enters the red giant phase. So there's lots of ways to tell a
star's age.

Yousuf Khan

[David Levy]

Thanks Mike

> You make it sound like a circular argument, but it isn't.

Do you mean that the current star age measurement doesn't depend on the
big bang theory?
If so, then a star age should not be measured based on its metallicities
composition.
Therefore, how do we currently estimate a star age?

> The age of the Earth had been fairly well established at about 4-4.5
> billion years.
I assume that the Science has estimated this age by measuring the solid
ground and rocks at the Earth. in this case a fundamental assumption was
taken - that the Earth was a rocky star from day one. Never the less, if
the Earth was born as a hot star with mixing boiled matter of melting
Lava and hot Gas, then by definition, there might be a sever error in
this age estimation.
Hence, for example - if it took the Earth 5 Billion year to cool down
the surface and set the first solid rocks and ground, than by definition
its age is 5 + 4.5 Billion years.
Do you agree?




--
David Levy

[Yousuf Khan]

On 18/05/2013 8:24 PM, David Levy wrote:
> Thanks Mike
>
>> You make it sound like a circular argument, but it isn't.
> Do you mean that the current star age measurement doesn't depend on the
> big bang theory?

Well, it does, but only indirectly. Everything in the Universe depends
on the BBT, but simply as a means to set the upper age limits. If for
example an object is found to be older than the BBT's estimate of the
age of the Universe, then there must be something wrong with the
estimate of the age of the object. Most objects have comfortably fit
under the age of the Universe, with a few being estimated to be older
based on the upper range of its error bars, but the lower range still
within, that's all.

> If so, then a star age should not be measured based on its metallicities
> composition.
> Therefore, how do we currently estimate a star age?

That's been explained to you in my other message to you. The
metallicities are basically some interesting factoids that differentiate
between 1st, 2nd, and 3rd generation stars, that's all. As an estimate
of star ages, they aren't all that useful.

>> The age of the Earth had been fairly well established at about 4-4.5
>> billion years.
> I assume that the Science has estimated this age by measuring the solid
> ground and rocks at the Earth. in this case a fundamental assumption was
> taken - that the Earth was a rocky star from day one. Never the less, if
> the Earth was born as a hot star with mixing boiled matter of melting
> Lava and hot Gas, then by definition, there might be a sever error in
> this age estimation.
> Hence, for example - if it took the Earth 5 Billion year to cool down
> the surface and set the first solid rocks and ground, than by definition
> its age is 5 + 4.5 Billion years.
> Do you agree?

Um, why are you calling the Earth, a star?

Yousuf Khan

[Mike Dworetsky]

David Levy wrote:
> Thanks Mike
>
>> You make it sound like a circular argument, but it isn't.
> Do you mean that the current star age measurement doesn't depend on
> the big bang theory?

Not really. Star ages are determined mainly by comparing observations of
their position in the HR diagram (luminosity and temperature, essentially)
with carefully worked-out theoretical calculations of the evolution of a
star. The details of the calculations depend on the composition of the star
or star cluster (more usually), but this is a second order effect.

> If so, then a star age should not be measured based on its
> metallicities composition.
> Therefore, how do we currently estimate a star age?

By detailed calculations of models of stars based on our knowledge of
physics or nuclear reactions, such as cross-sections, and also on our
detailed knowledge of the theory of behaviour of gases under extreme
conditions, for example degeneracy of stellar cores under extreme conditions
of temperature and pressure.

These calculations are compared with the HR diagrams of star clusters, and
the main evidence for the age of a cluster is found from the position of the
turn-off from the main sequence.

There is a general trend for the oldest stars (Population II) to have much
lower metal abundances than more recent stars (Population I) because metal
abundances started out as zero and stellar evolution gradually recycled
elements formed in stars back into the material that formed subsequent
generations. But composition also depends on where in the Galaxy a star
forms.

>
>> The age of the Earth had been fairly well established at about 4-4.5
>> billion years.
> I assume that the Science has estimated this age by measuring the
> solid ground and rocks at the Earth. in this case a fundamental
> assumption was taken - that the Earth was a rocky star from day one.

I do not understand why you think this, not do I understand why you call the
Earth a star.

The age of the Earth is assumed to be the same as the age of the solar
system itself, which has been accurately determined from the consistent
upper age limit of meteorites. This is also consistent with the age of the
Sun itself as deduced from evolutionary models and the structure of the
interior deduced from analysis of solar vibrations (helioseismology). For
example, this shows that the core of the Sun has a reduced hydrogen content
consistent within about +/-1% of the age fround from meteorites.

Surface rocks on the Earth itself have ages ranging up to around 4 billion
years (or perhaps a bit more). This limit merely tells us the last time
these rocks were melted. It is unlikely that older rocks can be found
because this was the time of the "Late Heavy Bombardment" when most of the
craters on the Moon formed, and the Earth was also heavily bombarded.

> Never the less, if the Earth was born as a hot star with mixing
> boiled matter of melting Lava and hot Gas, then by definition, there
> might be a sever error in this age estimation.

You assert this, but without any evidence at all.

> Hence, for example - if it took the Earth 5 Billion year to cool down
> the surface and set the first solid rocks and ground, than by
> definition its age is 5 + 4.5 Billion years.
> Do you agree?

No, assuming I am understanding what you are saying. The cooling of the
Earth did not take 5 billion years to form solid rocks. All the evidence
available shows that the Earth's surface cooled enough to form solid rock
(or oceans with crustal rock floors) pretty quickly once the early heavy
bombardments by planetesimals and asteroids ceased.

I suggest that you stop speculating and read a basic text book on astronomy
first. You will find far more detailed explanations of stellar evolution
and the history of the solar system there.

[oriel36]

On May 19, 9:40 am, "Mike Dworetsky"

<platinum...@pants.btinternet.com> wrote:

> I suggest that you stop speculating and read a basic text book on astronomy
> first.  You will find far more detailed explanations of stellar evolution
> and the history of the solar system there.
>
> --
> Mike Dworetsky
>
> (Remove pants sp*mbl*ck to reply)

Ah Mike,you haven't been keeping up with the latest news have
you ?.Stellar evolutionary processes have become far more interesting
lately and one of the few bright spots.no pun intended, amid the chaos
of empirical assertions is that stellar evolution may not be a simple
and single process from beginning to end and especially supernova
events.

There were no textbooks a decade ago describing the possibility that
supernova are a transition phase which give rise to solar systems
rather than the demise of a star but you could read about it in an
unmoderated Usenet forum and recently it has made its way into wider
circulation even in a vague way but containing the kernel of an idea
about a star surviving a supernova event.

That the progenitor star creates the nebula from which the elements of
a solar system are formed is tempting -

http://d1jqu7g1y74ds1.cloudfront.net/wp-content/uploads/2010/02/461.jpg

[Mike Dworetsky]

oriel36 wrote:
> On May 19, 9:40 am, "Mike Dworetsky"
> <platinum...@pants.btinternet.com> wrote:
>
>> I suggest that you stop speculating and read a basic text book on
>> astronomy first. You will find far more detailed explanations of
>> stellar evolution and the history of the solar system there.
>>
>> --
>> Mike Dworetsky
>>
>> (Remove pants sp*mbl*ck to reply)
>
> Ah Mike,you haven't been keeping up with the latest news have
> you ?.Stellar evolutionary processes have become far more interesting
> lately and one of the few bright spots.no pun intended, amid the chaos
> of empirical assertions is that stellar evolution may not be a simple
> and single process from beginning to end and especially supernova
> events.

99.99% (or more) of stars do not undergo a supernova explosion, as they are
not massive enough.

>
> There were no textbooks a decade ago describing the possibility that
> supernova are a transition phase which give rise to solar systems
> rather than the demise of a star but you could read about it in an
> unmoderated Usenet forum and recently it has made its way into wider
> circulation even in a vague way but containing the kernel of an idea
> about a star surviving a supernova event.
>
> That the progenitor star creates the nebula from which the elements of
> a solar system are formed is tempting -
>
> http://d1jqu7g1y74ds1.cloudfront.net/wp-content/uploads/2010/02/461.jpg

Can you provide a reference that includes papers in refereed research
literature? Usenet forums are not the most likely place where new and
exciting research will be published first.

The idea that a supernova explosion can trigger the collapse of a nearby
interstellar cloud and star formation has been around for a long time, and
some of the evidence is found in the isotopic make up of the solar system
itself. I'm not familiar with the website mentioned and I would rather not
go there in case it is a malware injection site. Just being cautious, of
course.

None of this has anything to do with my reply, though.

[Odysseus]

In article <pYydnQ1MjthYawXM...@bt.com>,
"Mike Dworetsky" <plati...@pants.btinternet.com> wrote:

> oriel36 wrote:

<snip>

> > That the progenitor star creates the nebula from which the elements of
> > a solar system are formed is tempting -
> >
> > http://d1jqu7g1y74ds1.cloudfront.net/wp-content/uploads/2010/02/461.jpg
>
> Can you provide a reference that includes papers in refereed research
> literature? Usenet forums are not the most likely place where new and
> exciting research will be published first.
>
> The idea that a supernova explosion can trigger the collapse of a nearby
> interstellar cloud and star formation has been around for a long time, and
> some of the evidence is found in the isotopic make up of the solar system
> itself. I'm not familiar with the website mentioned and I would rather not
> go there in case it is a malware injection site. Just being cautious, of
> course.

You've almost certainly seen it before: a close-up of Eta Carinae, the
Homunculus Nebula, showing the lobes of gas reminiscent of a p-orbital,
probably expanding debris from the star's XIX-century outburst.

This should be a safe version:
<https://en.wikipedia.org/wiki/File:EtaCarinae.jpg>

The main problem with Oriel's hypothesis AFAICT is that a cloud like
that around Eta Car is a short-lived phenomenon: in a few millennia it
will look more like the Bubble or the Veil, a sphere whose interior has
been 'swept clean', its surface a thin film of glowing shreds. (Assuming
there isn't another outburst in the meantime -- it looks like this star
is going to 'put up a fight'.) As you say, the collision of the
shock-front with the surrounding clouds of the Keyhole Nebula might
trigger star formation in any regions that get 'compacted', but no
nova-remnant-type cloud will itself be a likely protoplanetary nebula.

--
Odysseus

[oriel36]

On May 20, 2:45 am, Odysseus <odysseus1479...@yahoo-dot.ca> wrote:
> In article <pYydnQ1MjthYawXMnZ2dnUVZ8sSdn...@bt.com>,

>  "Mike Dworetsky" <platinum...@pants.btinternet.com> wrote:
>
> > oriel36 wrote:
>
> <snip>
>
> > > That the progenitor star creates the nebula from which the elements of
> > > a solar system are formed is tempting -
>
> > >http://d1jqu7g1y74ds1.cloudfront.net/wp-content/uploads/2010/02/461.jpg
>
> > Can you provide a reference that includes papers in refereed research
> > literature?  Usenet forums are not the most likely place where new and
> > exciting research will be published first.
>
> > The idea that a supernova explosion can trigger the collapse of a nearby
> > interstellar cloud and star formation has been around for a long time, and
> > some of the evidence is found in the isotopic make up of the solar system
> > itself.  I'm not familiar with the website mentioned and I would rather not
> > go there in case it is a malware injection site.  Just being cautious, of
> > course.
>
> You've almost certainly seen it before: a close-up of Eta Carinae, the
> Homunculus Nebula, showing the lobes of gas reminiscent of a p-orbital,
> probably expanding debris from the star's XIX-century outburst.
>
> This should be a safe version:
> <https://en.wikipedia.org/wiki/File:EtaCarinae.jpg>
>
> The main problem with Oriel's hypothesis AFAICT is that a cloud like
> that around Eta Car is a short-lived phenomenon: in a few millennia it
> will look more like the Bubble or the Veil, a sphere whose interior has
> been 'swept clean', its surface a thin film of glowing shreds.

The image was meant to convey that nebula form around stars prior to a
supernova event as a rough guide to the central idea that certain
stars going supernova create a solar system after the event rather
than the usual idea of the demise of a star.It is a radical idea
however the stellar evolutionary process of supernova has a more
defined geometry to it that I was working on years before it was
actually observed -

http://chem.tufts.edu/science/astronomy/images/sn1987a.jpg

I have a single copyright from 1990 where there are two external
rings and a smaller intersecting ring surrounding a Supernova star
whereas the first time anyone seen those images was in 1994 and I was
just as surprised as anyone else to see them.

Anyone can make an assertion that certain supernova events may be the
beginning of a solar system rather than the death of a star but as
always,it is the journey to the conclusion that matters rather than
the conclusion itself and there is not a single individual alive I
would care to explain that natural evolutionary processes,up to and
including stellar evolution,have a specific geometry attached and the
fact is I started to develop this view over 23 years ago.

As you say, the collision of the
> shock-front with the surrounding clouds of the Keyhole Nebula might
> trigger star formation in any regions that get 'compacted', but no
> nova-remnant-type cloud will itself be a likely protoplanetary nebula.
>
> --
> Odysseus

Suit yourself,it is easier for me to handle the elements in our own
solar system as arising from our own Sun from a different phase in its
life cycle while maintaining a rough distance to the nearest stars in
our galactic orbital circuit as it is neater and less unstable than
trying to look elsewhere for solar system elements and gets
researchers out of a horrific chicken/egg dilemma of what came first -
the star or the galaxy ?.

[oriel36]

On May 19, 4:58 pm, "Mike Dworetsky"

That invariably leads to the temptation to criticize the patronage of
modern peer review insofar as that system is designed to favor the
reputations and salaries of the reviewers rather than anything else
but I will forego any other comment as it is a waste of my valuable
time and energy.

The Usenet forums are the equivalent of the coffee shops of London in
the late 17th century when science was an enterprise based on
reputation and not salary and as I look around these modern coffee
shops where people like to come and work or pass the time away reading
or in conversation,perhaps things have come full circle apart from the
fact that communication is done electronically.I am not an empiricist
so I neither beg approval nor particularly want to pass judgment on
those who filter astronomical and terrestrial observations through
that system ,even retroactively where a lot of damage was done in
assembling a system based on double modeling.

For instance,the system of Copernicus is based on the fact that we are
on a moving Earth and all judgments of solar system structure and the
motions of planets is based on that view as opposed to the double
modeling of Newton who created a hypothetical observer on the Sun to
account for direct motions -

http://apod.nasa.gov/apod/image/0112/JuSa2000_tezel.gif

"For to the earth planetary motions appear sometimes direct, sometimes
stationary, nay, and sometimes retrograde. But from the sun they are
always seen direct,..." Newton

That perspective of Newton would not get past peer review were there
such a rigorous entity in existence when he wrote it and were he
subject to such an assemblage insofar as observed apparent retrogrades
differ between the inner and out planets in terms of cause.

The reason stellar evolution is one of the bright spots of empiricism
is that it concerns itself with evolutionary processes which do not
require interpretative shifts of perspective common to the higher end
of astronomy,unfortunately the empirical community is lacking in the
type of individuals who do not mix up processes with interpretative
astronomy .

> Mike Dworetsky
>
> (Remove pants sp*mbl*ck to reply)

In the unhurried atmosphere of a coffee shop I watch as academics
scramble to put a lot of work I have already done in order and most
times make a mess of it but every now and again I do encounter a
decent rendition such as the wandering Sun analemma as an exercise in
Chinese whispers seen in the 'talk' page as 'Historical shift in
meaning of Analemma' -

http://en.wikipedia.org/wiki/Talk:Analemma

It is amazing what individuals can achieve when the motivation is not
money or celebrity but reputation and therein you have your answer as
to why stellar evolution as a processes of immense efficiency and even
beauty has remained a private work for over 23 years and may end up
remaining that way,sadly of course.

[Martin Brown]

On 18/05/2013 15:24, David Levy wrote:
> Thanks Mike
>
>> You make it sound like a circular argument, but it isn't.

> Do you mean that the current star age measurement doesn't depend on the
> big bang theory?
> If so, then a star age should not be measured based on its metallicities
> composition.

It is a shorthand at least for stars since the earliest stars were made
from almost exclusively hydrogen and helium with only traces of metals.

> Therefore, how do we currently estimate a star age?

If you can weigh the star in a binary system, know how far away it is
and how bright then you can get an estimate of its age. The theory of
stellar evolution is pretty good these days and is backed up by the
experimental evidence of the H-R diagram.

>
>> The age of the Earth had been fairly well established at about 4-4.5
>> billion years.

> I assume that the Science has estimated this age by measuring the solid
> ground and rocks at the Earth. in this case a fundamental assumption was
> taken - that the Earth was a rocky star from day one. Never the less, if
> the Earth was born as a hot star with mixing boiled matter of melting
> Lava and hot Gas, then by definition, there might be a sever error in
> this age estimation.

No. The way it works is that when a rock solidifies it can no longer
exchange ions with its surroundings and the chemicals are locked in the
rock. Radioactive decay of uranium, potassium, neodymium, strontium and
other isotopic systems allow you to date rocks to the time when they
were last molten or freely able to exchange ions with their environment.

http://www4.nau.edu/insidenau/bumps/2010/8_27_10/meteorite.html

I am sceptical over their claimed 4 sig fig precision - I know how hard
these measurements are - but they are probably good to 3 digits.

Measuring the isotopic ratios of the stable isotopes to the radiogenic
ones gives you an estimate of the age of the rock. The clocks all agree
and these days they can do it on the tiniest crystals like zircons.

Zircons are so tough that they tend to survive remelts and machines like
the Shrimp at ANU can read them back like peeling an onion.

http://www.anu.edu.au/CSEM/machines/SHRIMP.htm

> Hence, for example - if it took the Earth 5 Billion year to cool down
> the surface and set the first solid rocks and ground, than by definition
> its age is 5 + 4.5 Billion years.
> Do you agree?

In principle that could be true, but in practice the oldest pieces of
space rock we have ever observed in the solar system date to 4.55by.

http://www.space.com/5164-oldest-asteroids-solar-system-identified.html

The age of a rock is the last time that it solidified and stopped
exchanging ions with its environment. This can be a real issue in
biological specimens that are preserved in peat bogs. Tending to bias
the age towards being more recent than it really is.

--
Regards,
Martin Brown

[David Levy]

Thanks Yousuf

> Well, it does, but only indirectly. Everything in the Universe depends
> on the BBT, but simply as a means to set the upper age limits.

So, the star age measurements is based on the BBT. Therefore, if the
science is using the current star age measurements to confirm the BBT
then by definition it sounds like circular argument.

> If for example an object is found to be older than the BBT's estimate
> of the age of the Universe, then there must be something wrong with the

> estimate of the age of the object.
Now, I really got lost. So if an object found to be older than the BBT's
estimation than it is Obvious for the science that the problem is with
estimation age of the object. Why is it? Why can't we estimate that
there might be a problem with the BBT??? Why???

Thanks Mike

> The age of the Earth is assumed to be the same as the age of the solar
> system itself, which has been accurately determined from the consistent
> upper age limit of meteorites.

There is some question mark about the upper limit of the meteorites.
Please see the following:
http://www.universetoday.com/19599/age-of-the-moon/#ixzz2TxPSdxPC

"More recent research measured tungsten content in rocks returned from
the moon. Tungsten-182 is what you get when hafnium-182 decays. So the
scientists measured the ratios of tungsten to hafnium to determine
exactly when the moon formed. This is where the number 4.527 billion
years (give or take 10 million years). One problem with this technique
is that it&#8217;s based on the relative age of meteorites used to
determine how old the Solar System is. If that research is incorrect,
these estimates for the age of the Moon might be incorrect too".

Thanks Martin

> Hence, for example - if it took the Earth 5 Billion year to cool down
> the surface and set the first solid rocks and ground, than by definition
> its age is 5 + 4.5 Billion years. Do you agree?
>

> In principle that could be true, but in practice the oldest pieces of
> space rock we have ever observed in the solar system date to 4.55by.

This is a critical issue. The Earth or the moon could be a molten ball
on their birthday as follow: "Our planet was probably still mostly a
molten ball of rock, and the impact of the Moon did little to change
that".
Hence, there is a chance that it took some time for the Erath & the Moon
to cool down and set the first solid rocks. Therefore, by adding all the
factors, there might be an error in their age estimation...
This might lead us to an error in the age estimation of the solar system
and so on.




--
David Levy

[Mike Dworetsky]

David Levy wrote:
> Thanks Yousuf
>> Well, it does, but only indirectly. Everything in the Universe
>> depends on the BBT, but simply as a means to set the upper age
>> limits.
>
> So, the star age measurements is based on the BBT. Therefore, if the
> science is using the current star age measurements to confirm the BBT
> then by definition it sounds like circular argument.

No, you misunderstand this. Star ages are based on observations of stars,
and comparisons with the theory of stellar structure and evolution.

>
>> If for example an object is found to be older than the BBT's
>> estimate of the age of the Universe, then there must be something
>> wrong with the estimate of the age of the object.
> Now, I really got lost. So if an object found to be older than the
> BBT's estimation than it is Obvious for the science that the problem
> is with estimation age of the object. Why is it? Why can't we
> estimate that there might be a problem with the BBT??? Why???

Because the error (formal statistical error based on the measurements) for
the Age of the Universe is fairly small, but the formal error for the
estimated age of one extremely old star is fairly large (due to
observational errors, calibration errors, and to estimated errors in the
theory used). Its formal age is slightly greater than the current Age of
the Universe, but the error on this formal value is large enough for it to
be consistent, with a lower bound less than 13.72 BY. It is only if you
think that scientists are using weasel words when they discuss errors that
you might conclude something is seriously wrong. All good scientists try to
do their best to estimate errors correctly.

>
> Thanks Mike
>
>> The age of the Earth is assumed to be the same as the age of the
>> solar system itself, which has been accurately determined from the
>> consistent upper age limit of meteorites.
>
> There is some question mark about the upper limit of the meteorites.
> Please see the following:
> http://www.universetoday.com/19599/age-of-the-moon/#ixzz2TxPSdxPC
>
> "More recent research measured tungsten content in rocks returned from
> the moon. Tungsten-182 is what you get when hafnium-182 decays. So the
> scientists measured the ratios of tungsten to hafnium to determine
> exactly when the moon formed. This is where the number 4.527 billion
> years (give or take 10 million years). One problem with this technique
> is that it&#8217;s based on the relative age of meteorites used to
> determine how old the Solar System is. If that research is incorrect,
> these estimates for the age of the Moon might be incorrect too".

Any way you look at this, however, there is no serious dispute about the age
of the oldest meteorites, and the above is only one determination among many
of the age of the Moon, which remains less than the age of the solar system.

>
> Thanks Martin
>
>> Hence, for example - if it took the Earth 5 Billion year to cool
>> down the surface and set the first solid rocks and ground, than by
>> definition its age is 5 + 4.5 Billion years. Do you agree?
>>
>> In principle that could be true, but in practice the oldest pieces of
>> space rock we have ever observed in the solar system date to 4.55by.
>
> This is a critical issue. The Earth or the moon could be a molten ball
> on their birthday as follow: "Our planet was probably still mostly a
> molten ball of rock, and the impact of the Moon did little to change
> that".
> Hence, there is a chance that it took some time for the Erath & the
> Moon to cool down and set the first solid rocks. Therefore, by adding
> all the factors, there might be an error in their age estimation...
> This might lead us to an error in the age estimation of the solar
> system and so on.

The age of the oldest terrestrial rocks corroborates the age of the solar
system from meteorites (by being less, as expected), but is not used to
determine the solar system age.

[oriel36]

On May 22, 7:30 am, "Mike Dworetsky"

'Big Bang' indeed !,the idea that you can not only observe the past
but the entire evolutionary timeline of the Universe directly is
pretty much the most repulsive notion ever devised as it is the
antithesis of reasoning itself -people have about as much a chance as
observing the Universal evolutionary timeline directly as they have of
observing their own evolutionary timeline from child to adult directly
and that this 'Big Bang mess is proposed and accepted by the majority
is the real horror story.

People who stand back from it all and survey the idea should feel
sickened because if they don't they haven't understood what
empiricists try to say about time,space,motion and evolution - it is
truly that shocking,dismal and dismaying.

[dlzc]

Dear Mike Dworetsky:

On Tuesday, May 21, 2013 11:30:55 PM UTC-7, Mike Dworetsky wrote:
> David Levy wrote:
>
> > Thanks Yousuf
>
> >> Well, it does, but only indirectly. Everything in
> >> the Universe depends on the BBT, but simply as a
> >> means to set the upper age limits.
>
> > So, the star age measurements is based on the BBT.
> > Therefore, if the science is using the current star
> > age measurements to confirm the BBT then by
> > definition it sounds like circular argument.
>
> No, you misunderstand this. Star ages are based on
> observations of stars, and comparisons with the
> theory of stellar structure and evolution.

... assuming they start with pure hydrogen, a resultant of the Big Bang. The "theory" compared against assumes eh star stars with pure hydrogen, and the star's composition is compared to a composition-with-age chart.

> >> If for example an object is found to be older
> >> than the BBT's estimate of the age of the Universe,
> >> then there must be something wrong with the
> >> estimate of the age of the object.
>
> > Now, I really got lost. So if an object found to be
> > older than the BBT's estimation than it is Obvious
> > for the science that the problem is with estimation
> > age of the object. Why is it? Why can't we estimate
> > that there might be a problem with the BBT??? Why???
>
> Because the error (formal statistical error based on
> the measurements) for the Age of the Universe is
> fairly small, but the formal error for the estimated
> age of one extremely old star is fairly large (due to
> observational errors, calibration errors, and to
> estimated errors in the theory used). Its formal age
> is slightly greater than the current Age of the
> Universe, but the error on this formal value is large
> enough for it to be consistent, with a lower bound
> less than 13.72 BY. It is only if you think that
> scientists are using weasel words when they discuss
> errors that you might conclude something is seriously
> wrong. All good scientists try to do their best to
> estimate errors correctly.

Excellent response.

...

> >> The age of the Earth is assumed to be the same
> >> as the age of the solar system itself, which has
> >> been accurately determined from the consistent
> >> upper age limit of meteorites.
>
> > There is some question mark about the upper limit
> > of the meteorites. Please see the following:
>
> > http://www.universetoday.com/19599/age-of-the-moon/#ixzz2TxPSdxPC
>
> > "More recent research measured tungsten content
> > in rocks returned from the moon. Tungsten-182 is
> > what you get when hafnium-182 decays. So the
> > scientists measured the ratios of tungsten to
> > hafnium to determine exactly when the moon formed.
> > This is where the number 4.527 billion years
> > (give or take 10 million years). One problem with

> > this technique is that it's based on the relative

> > age of meteorites used to determine how old the
> > Solar System is. If that research is incorrect,
> > these estimates for the age of the Moon might be
> > incorrect too".
>
> Any way you look at this, however, there is no
> serious dispute about the age of the oldest
> meteorites, and the above is only one determination
> among many of the age of the Moon, which remains
> less than the age of the solar system.

... and it assumes the Moon was an asteroid capture (essentially), to arrive at an anomaly. Is it still, if it is the result of a Theia collision?

...

> >> Hence, for example - if it took the Earth
> >> 5 Billion year to cool down the surface and set
> >> the first solid rocks and ground, than by
> >> definition its age is 5 + 4.5 Billion years. Do
> >> you agree?
>
> >> In principle that could be true, but in practice
> >> the oldest pieces of space rock we have ever
> >> observed in the solar system date to 4.55by.
>
> > This is a critical issue. The Earth or the moon
> > could be a molten ball on their birthday as
> > follow: "Our planet was probably still mostly a
> > molten ball of rock, and the impact of the Moon
> > did little to change that".
>
> > Hence, there is a chance that it took some time
> > for the Erath & the Moon to cool down and set the
> > first solid rocks. Therefore, by adding all the
> > factors, there might be an error in their age
> > estimation...
>
> > This might lead us to an error in the age
> > estimation of the solar system and so on.
>
> The age of the oldest terrestrial rocks corroborates
> the age of the solar system from meteorites (by being
> less, as expected), but is not used to determine
> the solar system age.

David A. Smith

[Steve Willner]

> On 17/05/2013 6:44 PM, David Levy wrote:
> > So the science is measuring the star age based on the fundamental Idea
> > of the Big bang.

Not true, as others have written. In any case, the Big Bang is now
so well supported by so many lines of evidence that using it as a
constraint on star ages is justified.

> > With the results of the star age they are coming back and reconfirm the
> > Big bang theory.

Star ages, where they can be measured independently, are consistent
with Big Bang theory, but they are not considered significant
evidence in favor of the Big Bang.

The Steady State model, referred to in a later post, is utterly
dead. The distant universe looks completely different from the local
universe, contrary to the basic Steady State prediction. I suppose
the Big Bang model could turn out to be wrong (though whatever
replaces it will have to look a lot like the Big Bang through the
last 10 or so Gyr), but Steady State is out.

In article <5197...@news.bnb-lp.com>,
Yousuf Khan <bbb...@spammenot.yahoo.com> writes:
> [Metallicity] only works for roughly comparing & categorizing really old stars

> (mainly first and second generation) vs. modern ones (third generation).

All basically correct but perhaps in need of some clarification.
With few exceptions, there is no mechanism for destroying metals once
created. Therefore, on average, metallicity increases with time. In
the Milky Way, there are no young stars with low metallicity because
the gas out of which stars form has long since been "polluted" with
metals. However, location matters, and young stars formed in the
Galactic outskirts can have lower metallicity than old stars formed
nearer the center.

As Yousuf Khan wrote:
> [age-metallicity] is not a linear relationship, you don't have

> successive generations of stars getting grittier and grittier.

Basically right, but there aren't strict generations; stars are
forming all the time in the Milky Way.

> The galaxies aren't getting more metallic,

Metallicity in individual galaxies is increasing with time but at
different rates in different galaxies.

> metallicity is hardly the only way to determine the age of a star,

As (I think) Mike and Martin wrote, metallicity is not a measure of
stellar age except in the crudest approximation. In fact, measuring
ages for individual stars is extremely difficult. Measuring ages for
star clusters is somewhat easier, though. The key is to determine
the mass of the most massive main sequence stars in the cluster, then
use stellar evolution theory to determine the main sequence lifetime
for stars at that mass. Because more massive stars have left the
main sequence, that gives the age of the cluster.

For ages of individual stars, you have to know quite a lot of
detailed information. State of the art is the Sun's age via
helioseismology, but that sort of detail isn't available for many
stars. There are rough indicators such as photospheric lithium
abundance (which decreases with age but reaches zero pretty quickly)
and chromospheric activity, but these are mainly relative indicators
for stars that are otherwise similar.

> all stars are 3rd generation now, so metallicity is not the only
> way to determine a star's age, nor even the best way.

Basically true for most stars. Some stars are "2nd generation"
(referred to as Population II, but the populations go the opposite
way to generations). Pop II stars have lower metallicity than "3rd
generation" (Pop I) stars, but as I wrote above, there is no direct
relation between metallicity and age for either population.

--
Help keep our newsgroup healthy; please don't feed the trolls.
Steve Willner Phone 617-495-7123 swil...@cfa.harvard.edu
Cambridge, MA 02138 USA

[Mike Dworetsky]

dlzc wrote:
> Dear Mike Dworetsky:
>
> On Tuesday, May 21, 2013 11:30:55 PM UTC-7, Mike Dworetsky wrote:
>> David Levy wrote:
>>
>>> Thanks Yousuf
>>
>>>> Well, it does, but only indirectly. Everything in
>>>> the Universe depends on the BBT, but simply as a
>>>> means to set the upper age limits.
>>
>>> So, the star age measurements is based on the BBT.
>>> Therefore, if the science is using the current star
>>> age measurements to confirm the BBT then by
>>> definition it sounds like circular argument.
>>
>> No, you misunderstand this. Star ages are based on
>> observations of stars, and comparisons with the
>> theory of stellar structure and evolution.
>
> ... assuming they start with pure hydrogen, a resultant of the Big
> Bang. The "theory" compared against assumes eh star stars with pure
> hydrogen, and the star's composition is compared to a
> composition-with-age chart.

You have a false notion of how models are made. Possibly you have some
incorrect notion of stellar evolution.

Not pure hydrogen, but hydrogen and helium, and it is not correct that
models assume no metals. The reason for this is that all stars that can be
observed today have some metals (though there are extreme very old stars
with very low metal content vs the Sun). The metal content affects the
opacity of the gas, which in turn affects the way the stars evolve.

Star compositions are determined directly by spectroscopy.

Various attempts have been made to model the "Population III" stars that
would have been the first to condense from the original gas mixture. There
would have been no dust--because there was no carbon, silicon, etc.
However, these cannot be compared observationally because no such stars have
been found, yet.

As far as I am aware, the collision theory is still the leading model for
the formation of the Moon.

[dlzc]

Dear Mike Dworetsky:

On Thursday, May 23, 2013 12:16:51 AM UTC-7, Mike Dworetsky wrote:

> dlzc wrote:
> > ... assuming they start with pure hydrogen, a
> > resultant of the Big Bang. The "theory" compared

> > against assumes [the star starts] with pure hydrogen,

> > and the star's composition is compared to a
> > composition-with-age chart.
>
> You have a false notion of how models are made.
> Possibly you have some incorrect notion of stellar
> evolution.

Well, it is a cinch that I cannot type. Hopefully corrected above. You got the gist, which means you are at least as smart as me...

> Not pure hydrogen, but hydrogen and helium, and
> it is not correct that models assume no metals.

The HR chart you referred to earlier, has a position on it for a star with pure* hydrogen. No? *Please understand that I mean by pure hydrogen, the initial mix the Big Bang is supposed to have produced (and note that this was established by observation of the mix, and not fundamental physics... it was tuned).

> The reason for this is that all stars that can be
> observed today have some metals (though there are
> extreme very old stars with very low metal content
> vs the Sun).

To play Devil's advocate, should some form of continuous Bang be going on (or white holes, or evaporating proto black holes), a pure* hydrogen star does not have to be old. For example globular clusters are assumed to be old, because there was a Big Bang, and that was the only time pure* hydrogen was available. Hence the OPs reference to circular argument. They also have been stripped of their dust (see below, and assuming they were the cores of smaller galaxies that lost their "disc stars" to the larger galaxy).

> The metal content affects the opacity of the gas,
> which in turn affects the way the stars evolve.
>
> Star compositions are determined directly by spectroscopy.
>
> Various attempts have been made to model the
> "Population III" stars that would have been
> the first to condense from the original gas
> mixture. There would have been no dust--because
> there was no carbon, silicon, etc.
>
> However, these cannot be compared observationally
> because no such stars have been found, yet.

We cannot image individual stars outside the Milky Way. So what we see, are illuminated dust clouds in more distant areas... a sort of shadow play. We cannot see the stars, only what they do to / through dust. So of course we see metallicity. Granted, if there is dust there, it is a good assumption those nearby stars are the source...

...

> >> Any way you look at this, however, there is no
> >> serious dispute about the age of the oldest
> >> meteorites, and the above is only one determination
> >> among many of the age of the Moon, which remains
> >> less than the age of the solar system.
>
> > ... and it assumes the Moon was an asteroid capture
> > (essentially), to arrive at an anomaly. Is it still,
> > if it is the result of a Theia collision?
>
> As far as I am aware, the collision theory is still
> the leading model for the formation of the Moon.

I was not challenging this.

The "anomaly" is the assumption that the Moon was a typical asteroid and was captured, not the isotopic age of its constituents as compared to typical asteroids.

So I was trying to talk to the OP about this particular item on his laundry list of anomalies that he has chosen because he thinks they "disprove" the Big Bang theory.

David A. Smith

[Steve Willner]

In article <1d830851-6c91-4b5a...@googlegroups.com>,
dlzc <dl...@cox.net> writes:
> *Please understand that I mean by pure hydrogen, the = initial mix
> the Big Bang is supposed to have produced (and note that this w= as

> established by observation of the mix, and not fundamental
> physics...

On the contrary, there are theoretical calculations of the light
nuclide abundances. Do a web search on "Big Bang Nucleosynthesis."
Observations agree with theory. I'm not sure which is considered
more accurate nowadays.

> To play Devil's advocate, should some form of continuous Bang be

> going on (= or white holes, or evaporating proto black holes),

or invisible fairies (but evaporating black holes would not be adding
to total mass)

> a pure* hydrogen star does not have to be old.

Logically correct, but there is no evidence for creation of new
matter. One would have to ask, though, if low-metal stars are
forming now, why don't we see any low-metal gas?

> globular clusters are assumed to be old , because there was a Big

> Bang, and that was the only time pure* hydrogen was available.

No. As has been written in this thread, globular clusters are
assumed to be old because of their HR diagrams. In particular, the
clusters contain no main sequence stars more massive than a fairly
small value. That's because (in the standard view), all stars with
larger mass have evolved away from the main sequence.

> Hence the OPs reference to circular argument

was mistaken.

> They also have been stripped of their dust

What makes you think globular clusters ever had dust (though they
probably did)? More relevant, they have been stripped of gas, or the
gas was entirely used up in forming the stars. What that has to do
with anything being discussed here escapes me.

> (see below, and assuming they were the cores =

> of smaller galaxies that lost their "disc stars" to the larger galaxy).

Globular clusters were the cores of galaxies?! Why would you suggest
that?

> We cannot image individual stars outside the Milky Way.

If you mean image the stellar surfaces, that's true. It's only
possible for stars that are both nearby and physically large. If you
mean see a star as separate from other stars in the same galaxy,
that's not entirely true. Bright stars can be resolved in nearby
galaxies and supernovae even in distant galaxies. Cepheid variables,
fore example, are particularly important for distance measurements.

> So what we see, are illuminated dust clouds in more distant areas

I have no idea what you mean by this. Galaxies in general are seen
as we see the Milky Way by naked eye: patches of light spread over a
finite area on the sky. The light comes from stars that are not
resolved individually, as Galileo discovered for the Milky Way. Dust
has nothing to do with it (in visible light) except that dust
extinction diminishes the light that would otherwise be seen.
(Reflection from dust is seen in a few rare cases but contributes a
miniscule fraction of the total light.)

[dlzc]

Dear Steve Willner:

On Thursday, May 23, 2013 3:38:10 PM UTC-7, Steve Willner wrote:
> In article <1d830851-6c91-4b5a-875c-e7abd1eb2***@googlegroups.com>,

>
> dlzc <dl***@cox.net> writes:
>
> > *Please understand that I mean by pure hydrogen,
> > the = initial mix the Big Bang is supposed to have

> > produced (and note that this was established by

> > observation of the mix, and not fundamental physics...
>
> On the contrary, there are theoretical calculations
> of the light nuclide abundances. Do a web search on
> "Big Bang Nucleosynthesis." Observations agree with
> theory. I'm not sure which is considered more
> accurate nowadays.

This is not my dog. We will see what the OP does with it.

> > To play Devil's advocate, should some form of
> > continuous Bang be going on (= or white holes,
> > or evaporating proto black holes),
>
> or invisible fairies (but evaporating black holes
> would not be adding to total mass)

... but could be adding hydrogen...

> > a pure* hydrogen star does not have to be old.
>
> Logically correct, but there is no evidence for
> creation of new matter.

We have not been looking very long. I tend to agree with you. New discoveries (a close cold galaxy 5 - 10 years ago) are due to improvements in observation.

> One would have to ask, though, if low-metal stars are
> forming now, why don't we see any low-metal gas?

With space filled (in some sense) with ionized hydrogen and oxygen missing 5 electrons, how would we know if some of the hydrogen was new?

> > globular clusters are assumed to be old ,
> > because there was a Big Bang, and that was the only
> > time pure* hydrogen was available.
>
> No. As has been written in this thread, globular
> clusters are assumed to be old because of their HR
> diagrams.

Which was in turn, scaled in light of a Big Bang.

> In particular, the clusters contain no main
> sequence stars more massive than a fairly
> small value. That's because (in the standard view),
> all stars with larger mass have evolved away from
> the main sequence.

Better. Much better.

> > Hence the OPs reference to circular argument
>
> was mistaken.

I seem unable to get you to see that he really was not.

> > They also have been stripped of their dust
>
> What makes you think globular clusters ever had
> dust (though they probably did)? More relevant,
> they have been stripped of gas, or the gas was
> entirely used up in forming the stars. What that
> has to do with anything being discussed here
> escapes me.

"The oldest stars..."

> > (see below, and assuming they were the cores =
> > of smaller galaxies that lost their "disc stars"
> > to the larger galaxy).
>
> Globular clusters were the cores of galaxies?! Why
> would you suggest that?

They seem extremely similar to the center of a spiral galaxy. They also have black holes.
http://arxiv.org/abs/1207.3795

> > We cannot image individual stars outside the
> > Milky Way.
>
> If you mean image the stellar surfaces, that's
> true. It's only possible for stars that are both
> nearby and physically large. If you mean see a
> star as separate from other stars in the same galaxy,
> that's not entirely true. Bright stars can be
> resolved in nearby galaxies and supernovae even in
> distant galaxies. Cepheid variables, fore example,
> are particularly important for distance measurements.

... and even then it is non-trivial to locate the container galaxy.

> > So what we see, are illuminated dust clouds in
> > more distant areas
>
> I have no idea what you mean by this.

It would help if you did not cut the quote off mid-sentence.

> Galaxies in general are seen as we see the Milky Way
> by naked eye: patches of light spread over a
> finite area on the sky.

Or the bullet cluster, where "all" the dust is removed, and we can see none of the stars.

> The light comes from stars that are not resolved
> individually, as Galileo discovered for the Milky
> Way. Dust has nothing to do with it (in visible
> light) except that dust extinction diminishes the
> light that would otherwise be seen.

When yo look at a nebula, say the ring nebula, what is its most prominent feature, the white dwarf, or the nebula?

> (Reflection from dust is seen in a few rare
> cases but contributes a miniscule fraction of
> the total light.)

OK, unless you have something for me, you can end this as you see fit.

David A. Smith

[Odysseus]

In article <jdGdnUeDxrj5XwDM...@bt.com>,
"Mike Dworetsky" <plati...@pants.btinternet.com> wrote:

<snip>

> Various attempts have been made to model the "Population III" stars that
> would have been the first to condense from the original gas mixture. There
> would have been no dust--because there was no carbon, silicon, etc.
> However, these cannot be compared observationally because no such stars have
> been found, yet.

If earlier stars were bigger than those of later generations, as has
been suggested, one wouldn't expect many of them to be left in a
non-degenerate state, having made their trips off the main sequence eons
before the Sun was formed. Unless their evolution takes a different
course from higher-metallicity stars, any of Pop. III still surviving
would be small, long-lived dwarfs. It's only in recent years we've been
able to detect or characterize faint red dwarfs beyond our immediate
neighbourhood (lists of the N nearest stars are still getting updated
every couple of years, where N is a surprisingly small number), which
may not be representative of the Galaxy as a whole.

--
Odysseus

[oriel36]

On May 22, 8:54 pm, will...@cfa.harvard.edu (Steve Willner) wrote:
> > On 17/05/2013 6:44 PM, David Levy wrote:
> > > So the science is measuring the star age based on the fundamental Idea
> > > of the Big bang.
>
> Not true, as others have written.  In any case, the Big Bang is now
> so well supported by so many lines of evidence that using it as a
> constraint on star ages is justified.
>

'Big bang' is so logically corrupt that it requires a dysfunctional
mind to ignore the internal inconsistencies or rather,the acceptance
of logical consistency.

Because the idea of past is bumped up to present observations as an
evolutionary timeline it means that the oldest galaxies being the
furthest in a smaller Universe will generate, by logical consistency,
the perception that the nearest galaxies are the youngest in a larger
Universe.I wouldn't know what to make of people who propose such a
structure but that is exactly what the wider view looks like.

> Help keep our newsgroup healthy; please don't feed the trolls.

> Steve Willner            Phone 617-495-7123     swill...@cfa.harvard.edu
> Cambridge, MA 02138 USA

[Mike Dworetsky]

Odysseus wrote:
> In article <jdGdnUeDxrj5XwDM...@bt.com>,
> "Mike Dworetsky" <plati...@pants.btinternet.com> wrote:
>
> <snip>
>
>> Various attempts have been made to model the "Population III" stars
>> that would have been the first to condense from the original gas
>> mixture. There would have been no dust--because there was no
>> carbon, silicon, etc. However, these cannot be compared
>> observationally because no such stars have been found, yet.
>
> If earlier stars were bigger than those of later generations, as has
> been suggested, one wouldn't expect many of them to be left in a
> non-degenerate state, having made their trips off the main sequence
> eons before the Sun was formed. Unless their evolution takes a
> different course from higher-metallicity stars, any of Pop. III still
> surviving would be small, long-lived dwarfs. It's only in recent

Yes, this is correct, and the search goes on. But so far, nothing like a
Pop III dwarf star has been found. Some stars of astonishingly low metal
abundance have been found (10^-3 to 10^-4 of solar abundances, IIRC). For
various reasons involving the dynamics of older stars, the search is usually
conducted by examining stars in the galactic halo.

> years we've been able to detect or characterize faint red dwarfs
> beyond our immediate neighbourhood (lists of the N nearest stars are
> still getting updated every couple of years, where N is a
> surprisingly small number), which may not be representative of the
> Galaxy as a whole.

Arguments that we do not see Pop III stars because we happen to be located
in a special area of the Galaxy where they do not occur, suffer from the
violation of the Principle of Mediocrity, or the Copernican Principle, which
says that we are not located in a special or privileged place.

To claim it is true requires special pleading.

[oriel36]

On May 24, 8:37 am, "Mike Dworetsky"

<platinum...@pants.btinternet.com> wrote:

> Arguments that we do not see Pop III stars because we happen to be located
> in a special area of the Galaxy where they do not occur, suffer from the
> violation of the Principle of Mediocrity, or the Copernican Principle, which
> says that we are not located in a special or privileged place.
>

You display all the traits of a cult mind and this trumped up idea of
the 'Copernican Principle' which is merely late 20th century junk
imposed on history.

The objection of the Pope in the Galileo affair had nothing to do with
a supposed central Earth nor a stationary Sun,the genuine astronomical
objections which still hold true today was whether the facility for
predicting astronomical events like eclipses and transits as days and
dates within the calendar framework be also used to extrapolate the
planetary dynamics of the Earth -

"Here lurked the danger of serious misunderstanding. Maffeo Barberini,
while he was a Cardinal, had counselled Galileo to treat Copernicanism
as a hypothesis, not as a confirmed truth. But ‘hypothesis’ meant two
very different things. On the one hand, astronomers were assumed to
deal only with hypotheses, i.e. accounts of the observed motions of
the stars and planets that were not claimed to be true. Astronomical
theories were mere instruments for calculation and prediction, a view
that is often called ‘instrumentalism’. On the other hand, a
hypothesis could also be understood as a theory that was not yet
proved but was open to eventual confirmation. This was a ‘realist’
position. Galileo thought that Copernicanism was true, and presented
it as a hypothesis, i.e. as a provisional idea that was potentially
physically true, and he discussed the pros and cons, leaving the issue
undecided. This did not correspond to the instrumentalist view of
Copernicanism that was held by Maffeo Barberini and others. They
thought that Copernicus’ system was a purely instrumental device, and
Maffeo Barberini was convinced that it could never be proved. This
ambiguity pervaded the whole Galileo Affair."

http://www.unav.es/cryf/english/newlightistanbul.html

When the unfortunate Flamsteed correlated a rotating celestial sphere
with a rotating Earth using the 24 hour AM/PM cycle within the
365/365/365/366 day framework so began empirical homocentricity which
is the worst of the worst.so bad that the astronomers before
Copernicus sought out arguments for the Earth's motions as it would
create the horror of homocentricity where every point would be the
center of the Universe -

"Thereupon you will see-- through the intellect..that the world and
its motion and shape cannot be apprehended. For the universe will
appear as a wheel in a wheel and a sphere in a sphere-- having its
center and circumference nowhere. . . " Nicolas of Cusa 16th century

Mediocrity principle indeed !,try looking in the mirror.

[David Levy]

Thanks All

> - David: Hence, for example - if it took the Earth 5 Billion year to

> cool down the surface and set the first solid rocks and ground, than by

> definition its age is 5 + 4.5 Billion years. Do you agree? -
> - Yousuf: In principle that could be true, but in practice the oldest
> pieces of
> space rock we have ever observed in the solar system date to 4.55by. -
> - David: This is a critical issue. The Earth or the moon could be a

> molten ball on their birthday as follow: "Our planet was probably still
> mostly a molten ball of rock, and the impact of the Moon did little to
> change that". Hence, there is a chance that it took some time for the
> Erath & the Moon to cool down and set the first solid rocks. Therefore,
> by adding all the factors, there might be an error in their age
> estimation... This might lead us to an error in the age estimation of

> the solar system and so on. -
> - Martin: The age of the oldest terrestrial rocks corroborates the age

> of the solar system from meteorites (by being less, as expected), but is
> not used to determine the solar system age.

> dlzc (David A. Smith): .... assuming they start with pure hydrogen, a

> resultant of the Big Bang. The "theory" compared against assumes eh star
> stars with pure hydrogen, and the star's composition is compared to a

> composition-with-age chart. -
So yes, the age of the oldest meteorites is clear. But, this can only
give us the minimum lever of the Solar system age.
By : http://www4.nau.edu/insidenau/bumps/2010/8_27_10/meteorite.html
"Their findings dated the piece at 4.568 billion years old, or nearly 2
million years older than the oldest materials found in other
meteorites&#8230; For nearly 10 years they have classified and studied
more than 1,000 meteorites, which include 22 lunar and 14 Martian
meteorites, and have published dozens of research papers on the topic."
Out of the Billion over Billion meteorites & Asteroids we have verified
the age of about 1000. We have found that the oldest is about 4.568
Billion years old. Does it mean that there is no possibility that there
are some others which might be older???
The upper lever of the solar age can't be determined by only 1000 pcs
which we have in our hand. Therefore it can only give us an indication
that the lower limit age of the solar system or even the Earth is 4.568
billion years.
With Regards to the Earth &#8211; Yes, we must measure the age of the
"oldest terrestrial rocks". Unfortunately, as the petroleum is located
deep in the ground, it's quite clear that the majority of the oldest
terrestrial rocks are located today deep in the ground. As over 70% of
the Earth is cover with Oceans, then, there is a chance that there is no
access today to the real oldest terrestrial rocks. Therefore, the rocks
which are considered to be the oldest terrestrial rocks, give us an
indication for the Min. age of the Earth.
Even so, those oldest terrestrial rocks might be molten lava on the day
that the Earth was born. We don't know for sure how long it took for the
Earth to cool down and set the first solid rock. Therefore, even those
achievable oldest terrestrial rocks can't give an indication for the
real age of the Earth.
> - David: So, the star age measurements is based on the BBT. Therefore,

> if the science is using the current star age measurements to confirm the
> BBT

> then by definition it sounds like circular argument. -
> - Mike: No, you misunderstand this. Star ages are based on observations

> of stars, and comparisons with the theory of stellar structure and

> evolution. -
By Wiki &#8211; "Stellar populations are categorized as I, II, and
III&#8230; Soon after the Big Bang, without metals, it is believed that
only stars with masses hundreds of times that of the Sun could be
formed;
Hence &#8211; the whole Idea of the stellar population is based on the
BBT. Therefore, by definition this is a circular argument!!!
Even so, there are some other issues as follow:
By Wiki - http://en.wikipedia.org/wiki/Stellar_evolution
"A stellar evolutionary model is a mathematical model that can be used
to compute the evolutionary phases of a star from its formation until it
becomes a remnant... Accurate models can be used to estimate the current
age of a star by comparing its physical properties with those of stars
along a matching evolutionary track.[26]"
Hence &#8211; the stellar evaluation model is based on the fundamental
idea of comparing a star with a matching evolutionary track. This is
O.K. if you base the theory on the BBT and you know for sure the age of
the matching evolutionary stars. Unfortunately we also don't know for
sure even the age of the Earth. So how can we set this kind of matching
process???
With regards to the BBT &#8211; I fully agree with David A. Smith.
> - dlzc (David A. Smith): .... assuming they start with pure hydrogen,

> a resultant of the Big Bang. The "theory" compared against assumes eh
> star stars with pure hydrogen, and the star's composition is compared to

> a composition-with-age chart. -
But what if they didn't start with pure Hydrogen??? What if it started
differently??? How can we know for sure what is correctd theory???
With regards to Steve message -
> - Steve: The Big Bang is now so well supported by so many lines of
> evidence that using it as a constraint on star ages is justified&#8230;

> I suppose the Big Bang model could turn out to be wrong (though whatever
> replaces it will have to look a lot like the Big Bang through the last

> 10 or so Gyr), but Steady State is out. -
Hence, In one hand you write that just by setting the BBT as the
mainstream of the modern science, it is justified to use it for star age
measurements, So it is O.K. for you to use the BBT in a circular
argument. In the other hand you mention that there is a chance (even a
very small chance...) that the BBT will be turned out wrong.
Therefore, I strongly suggest that the science should not verify and set
the age measurements based on BBT & its supportive theories!!!
We must find a correct process for age measurments!!!




--
David Levy

[Mike Dworetsky]

No, the idea of stellar populations originated with Walter Baade's
observations comparing young disk populations in spiral galaxies with old
populations in the halo. These ideas were presented long before anyone
proposed the Big Bang Theory.

The idea of an even older "Pop III" was proposed much later.

> Even so, there are some other issues as follow:
> By Wiki - http://en.wikipedia.org/wiki/Stellar_evolution
> "A stellar evolutionary model is a mathematical model that can be used
> to compute the evolutionary phases of a star from its formation until
> it becomes a remnant... Accurate models can be used to estimate the
> current age of a star by comparing its physical properties with those
> of stars along a matching evolutionary track.[26]"
> Hence &#8211; the stellar evaluation model is based on the fundamental
> idea of comparing a star with a matching evolutionary track. This is
> O.K. if you base the theory on the BBT and you know for sure the age
> of the matching evolutionary stars. Unfortunately we also don't know
> for sure even the age of the Earth. So how can we set this kind of
> matching process???

You look up all the gas laws, including how to deal with degenerate gases,
then you add knowledge of nuclear reactions from laboratory experiments, for
which published reaction rates exist, then you make a numerical model of a
star using gravitation and thermodymamics, and calculate what such a star
would look like as it ages. A good computer programmed for numerical
calculations of stellar structure including time steps is needed. You then
compare the theory and observation and look for a match. If a set of models
of a particular age matched the distribution of star colours and magnitudes
in a cluster and then for a set of models then you can determine the age of
the cluster. BBT absolutely does not come into it.

> With regards to the BBT &#8211; I fully agree with David A. Smith.
>> - dlzc (David A. Smith): .... assuming they start with pure
>> hydrogen, a resultant of the Big Bang. The "theory" compared against
>> assumes eh star stars with pure hydrogen, and the star's composition
>> is compared to a composition-with-age chart. -
> But what if they didn't start with pure Hydrogen??? What if it
> started differently??? How can we know for sure what is correctd
> theory???
> With regards to Steve message -
>> - Steve: The Big Bang is now so well supported by so many lines of
>> evidence that using it as a constraint on star ages is
>> justified&#8230; I suppose the Big Bang model could turn out to be
>> wrong (though whatever replaces it will have to look a lot like the
>> Big Bang through the last 10 or so Gyr), but Steady State is out. -
> Hence, In one hand you write that just by setting the BBT as the
> mainstream of the modern science, it is justified to use it for star
> age measurements, So it is O.K. for you to use the BBT in a circular
> argument. In the other hand you mention that there is a chance (even a
> very small chance...) that the BBT will be turned out wrong.
> Therefore, I strongly suggest that the science should not verify and
> set the age measurements based on BBT & its supportive theories!!!
> We must find a correct process for age measurments!!!

Too many exclamation marks. Calm down and think.

[Odysseus]

In article <c_adnSfboN5XhQLM...@bt.com>,
"Mike Dworetsky" <plati...@pants.btinternet.com> wrote:

> Odysseus wrote:

<snip>

> > If earlier stars were bigger than those of later generations, as has
> > been suggested, one wouldn't expect many of them to be left in a
> > non-degenerate state, having made their trips off the main sequence
> > eons before the Sun was formed. Unless their evolution takes a
> > different course from higher-metallicity stars, any of Pop. III still
> > surviving would be small, long-lived dwarfs. It's only in recent
>
> Yes, this is correct, and the search goes on. But so far, nothing like a
> Pop III dwarf star has been found. Some stars of astonishingly low metal
> abundance have been found (10^-3 to 10^-4 of solar abundances, IIRC). For
> various reasons involving the dynamics of older stars, the search is usually
> conducted by examining stars in the galactic halo.
>
> > years we've been able to detect or characterize faint red dwarfs
> > beyond our immediate neighbourhood (lists of the N nearest stars are
> > still getting updated every couple of years, where N is a
> > surprisingly small number), which may not be representative of the
> > Galaxy as a whole.
>
> Arguments that we do not see Pop III stars because we happen to be located
> in a special area of the Galaxy where they do not occur, suffer from the
> violation of the Principle of Mediocrity, or the Copernican Principle, which
> says that we are not located in a special or privileged place.
>
> To claim it is true requires special pleading.

JFTR I wasn't claiming anything of the kind, but pointing out that our
observational knowledge of such objects is comparatively poor, and -- as
your mention of the galactic halo suggests -- the oldest generation may
be less likely to be found here in the galactic disc than elsewhere, for
reasons having nothing to do with 'exceptionalism' but with the way the
structure of the Galaxy has evolved. We're also poorly placed to spot
faint, cool objects near the hub, for example, because of the dust and
gas in the intervening arms -- nothing special to the solar system
itself, but a fact of life anywhere in the mid-outer to outer portions
of the disc.

--
Odysseus

[Mike Dworetsky]

I'm happy to accept your explanation. The wording of the last sentence
suggested my interpretation.

One point worth making is that the halo is a preferred searching ground in
part because halo stars are known to be preferentially of low metal
abundance. On the other hand, the galactic hub is generally richer in heavy
elements than the part of the galactic plane near the Sun. What you say is
possible, but I think unlikely.

Any remaining Pop III stars would be around 1/2 solar mass or less, hence
very faint intrinsically, making the search difficult. There have been
theoretical discussions of why such small stars might never have formed, but
I don't know if that is still an accepted view.

[Steve Willner]

SW> One would have to ask, though, if low-metal stars are
SW> forming now, why don't we see any low-metal gas?

In article <6ce1c73f-5e12-4fc3...@googlegroups.com>,

dlzc <dl...@cox.net> writes:
> With space filled (in some sense) with ionized hydrogen and oxygen
> missing 5 electrons, how would we know if some of the hydrogen was
> new?

What gas has oxygen missing five electrons? More to the point, I
thought you were suggesting stars forming out of "new hydrogen" that
lacks metals. If that's happening, where is this low-metallicity
gas, and why don't we see it?

SW> As has been written in this thread, globular
SW> clusters are assumed to be old because of their HR diagrams.

> Which was in turn, scaled in light of a Big Bang.

Why do you continue to assert that? As has been explained _multiple_
times in this thread, the cluster ages are based entirely on atomic
physics. In other words, we observe a cluster with a maximum main
sequence luminosity of, say, half a solar luminosity. Via stellar
evolution theory (detailed computer models), stars of that luminosity
have about 0.8 solar masses and take about 9 Gyr to evolve off the
main sequence. (I'm making up all the numbers, but they are probably
in the ballpark.) Thus the cluster is 9 Gyr old. This has nothing
whatever to do with the Big Bang.

The models might, of course, be wrong (though they are well tested on
the Sun, for example, and other stars for which one can measure
independent masses or structures), but there is nothing circular
about the reasoning.

> Or the bullet cluster, where "all" the dust is removed, and we can
> see none of the stars.

You have some strange misconception, but I'm baffled by what it could
be. Are you equating "dust" with "dark matter?" Dust is dark in
visible light, but it isn't what is meant by "dark matter." In
particular, most dust glows quite nicely in the infrared, and in any
case there are direct methods of detecting dust. In all cases I can
think of, it is a tiny fraction of the mass.

Interpretation of the Bullet Cluster has nothing to do with dust.

> When yo look at a nebula, say the ring nebula, what is its most
> prominent feature, the white dwarf, or the nebula?

What does this have to do with the light from galaxies? A gaseous
nebula is an extended source of light. Sizes run from perhaps a
tenth of a parsec to tens of parsecs. A collection of stars, if you
have high enough resolution, can be separated into individual
objects. Separations are typically a parsec near the Sun and
somewhat smaller in globular clusters or galactic cores. (If you
have resolution 7 or 8 orders of magnitude better than a parsec, you
could resolve the stellar surfaces themselves, but that's quite a
leap from resolving the cluster or galaxy.)

[dlzc]

Dear Steve Willner:

On Wednesday, May 29, 2013 2:00:02 PM UTC-7, Steve Willner wrote:
> SW> One would have to ask, though, if low-metal stars are
> SW> forming now, why don't we see any low-metal gas?
>

> In article <6ce1c73f-5e12-4fc3-accd-008c7233e***@googlegroups.com>,

>
> dlzc <dl***@cox.net> writes:
>
> > With space filled (in some sense) with ionized
> > hydrogen and oxygen missing 5 electrons, how
> > would we know if some of the hydrogen was new?
>
> What gas has oxygen missing five electrons?

http://arstechnica.com/science/2012/09/milky-ways-missing-atoms-may-be-in-a-hot-cloud-surrounding-us/
http://www.princeton.edu/pr/pwb/00/0522/p/lostfound.shtml
http://astronomy.nmsu.edu/cwc/Group/QALsims/

> More to the point, I thought you were suggesting
> stars forming out of "new hydrogen" that lacks
> metals. If that's happening, where is this
> low-metallicity gas, and why don't we see it?

Ionized gas is hard to see in visible range, unless pressure is high enough to allow recombination.

> SW> As has been written in this thread, globular
> SW> clusters are assumed to be old because of

> SW> their HR diagrams.

>
> > Which was in turn, scaled in light of a Big Bang.
>
> Why do you continue to assert that?

What logic was used to arrive at "0 age"? I am continually told I am "wrong", without citation.

> As has been explained _multiple_ times in this
> thread, the cluster ages are based entirely on
> atomic physics. In other words, we observe a
> cluster with a maximum main sequence luminosity
> of, say, half a solar luminosity. Via stellar
> evolution theory (detailed computer models),

*calibrated how*?

> stars of that luminosity have about 0.8 solar
> masses and take about 9 Gyr to evolve off the
> main sequence. (I'm making up all the numbers,
> but they are probably in the ballpark.) Thus
> the cluster is 9 Gyr old. This has nothing
> whatever to do with the Big Bang.

Yes, you keep saying that...

> The models might, of course, be wrong (though
> they are well tested on the Sun, for example,
> and other stars for which one can measure
> independent masses or structures), but there
> is nothing circular about the reasoning.

And you keep saying that too.

> > Or the bullet cluster, where "all" the dust
> > is removed, and we can see none of the stars.
>
> You have some strange misconception, but I'm
> baffled by what it could be. Are you equating
> "dust" with "dark matter?"

Dust is lit by visible light, and consequently makes the associated stars look somewhat cooler. But also large enough to see at that distance.

> Dust is dark in visible light, but it isn't
> what is meant by "dark matter." In particular,
> most dust glows quite nicely in the infrared,
> and in any case there are direct methods of
> detecting dust. In all cases I can think of, it
> is a tiny fraction of the mass.

Yes, just drying to get to the "visibility". We know there are extra-galactic stars by the "scads", but we cannot see them, since they have no dust...

> Interpretation of the Bullet Cluster has
> nothing to do with dust.

I disagree, but let's move on. Again, I am simply filling in where the OP is lacking in clarity... and I guess I am doing poorly.

> > When yo look at a nebula, say the ring nebula,
> > what is its most prominent feature, the white
> > dwarf, or the nebula?
>
> What does this have to do with the light from
> galaxies?

Visibility. You keep asking me where this gas is, and I keep pointing out we "only" know where the dust is that is "backlit", like a shadow play. So we don't even know where the *stars* are.

> A gaseous nebula is an extended source of light.
> Sizes run from perhaps a tenth of a parsec to
> tens of parsecs. A collection of stars, if you
> have high enough resolution, can be separated into
> individual objects. Separations are typically a
> parsec near the Sun and somewhat smaller in
> globular clusters or galactic cores. (If you
> have resolution 7 or 8 orders of magnitude better
> than a parsec, you could resolve the stellar
> surfaces themselves, but that's quite a leap from
> resolving the cluster or galaxy.)

Sidelight... if we had three satellites in trojan with Earth, could we do VBLA techniques to achieve such resolution?

Seriously Steve, if you need to end this, just don't ask me questions. The OP has lamed out, so no need in continuing unless you need to hammer the lid on some "crap" I have spouted...

And thank you.

David A. Smith

[Steve Willner]

SW> What gas has oxygen missing five electrons?

In article <3311024f-acd8-463b...@googlegroups.com>,

dlzc <dl...@cox.net> writes:
> http://arstechnica.com/science/2012/09/milky-ways-missing-atoms-may-be-in-a-hot-cloud-surrounding-us/
> http://www.princeton.edu/pr/pwb/00/0522/p/lostfound.shtml
> http://astronomy.nmsu.edu/cwc/Group/QALsims/

The first two refer to extremely hot and low-density gas that isn't
forming stars. I'm not sure of the point of the third one. Yes, the
very tenuous intergalactic gas is probably low metallicity, but I
doubt it's primordial. Wasn't the recent detection in X-rays based
on an iron line?

> Ionized gas is hard to see in visible range, unless pressure is
> high enough to allow recombination.

You meant "temperature is low enough" in that last (though density
comes into it, too). However, most (if not all) regions in the Milky
Way where we know stars are forming are associated with ionized gas,
and we can measure the gas metallicity. It's roughly solar,
depending on the specific cloud.

> What logic was used to arrive at "0 age"?

Any cluster with high luminosity (=high mass) stars must be young.
That mostly means open clusters rather than globulars; the Orion
Nebula cluster is (without looking up the actual value) probably at
most a few Myr old. The Pleiades age estimate changed a few years
ago, but I think it's of order 100 Myr now.

> I am continually told I am "wrong", without citation.

It's easy to look in ADS.

http://adsabs.harvard.edu/abs/2013A%26A...549A..60C
is a recent detailed analysis of many globular clusters in M31 and
the Milky Way. The lowest age they find is 150 Myr.

http://adsabs.harvard.edu/abs/2010PASP..122..991D
is a detailed analysis of one specific cluster.

As I say, it's not hard to find more, and there are probably course
lecture notes on the web.

SW> Via stellar evolution theory (detailed computer models),

> *calibrated how*?

I'm not an expert, but models have to fit the Sun, which has
exquisite helioseismology results for all but the inner 5% of its
radius. Some other stars have stellar seismology, and stars in
binary systems have known masses and distances. Models also have to
fit laboratory data on opacity and nuclear cross sections. All that
doesn't mean the models are perfect, but the models assume nothing
whatever about a Big Bang or any other cosmology.

Why do you think the reasoning is circular? Do you think astronomers
wouldn't be aware of it if it were?

> Dust is lit by visible light, and consequently makes the associated
> stars look somewhat cooler. But also large enough to see at that
> distance.

Ah. That's a misconception all right. You can take credit for its
originality.

The Sun has an absolute visual magnitude of 4.8. If you put it at
the distance of the Virgo Cluster, which has a distance modulus of
about 31, the Sun would have an apparent magnitude of about 36.
That's far too faint to see with existing instruments, but it's not
zero flux density. Add, say, 10^11 similar stars, and the apparent
magnitude of the collection would be 8.5, easily visible in a small
telescope. In fact, M87, the brightest galaxy in the cluster, has a
visual magnitude of around 8.6, pretty close to this figure.

None of this has anything to do with dust, let alone making a star
"large enough to see." There are only rare instances in astronomy
where visible light is seen via reflection from dust. (You can look
up "reflection nebulae" for the most prominent examples.) Typically
dust along the line of sight absorbs light on its way to us and
thereby makes stars appear fainter than they would if there were no
dust. Dust absorbs blue light more than red light, so it also makes
stars appear redder. (Maybe that's what you were thinking of when
you wrote "somewhat cooler.") Taking this into account is not always
easy, but most globular clusters have essentially no internal dust.
Adding dust would make them fainter, not brighter. (All this refers
to visible light. Things are different in the infrared, where the
dust actually does emit light, but even there, reflection is not
relevant in most cases.)

> We know there are extra-galactic stars by the "scads", but we
> cannot see them, since they have no dust...

That last isn't the reason. Adding dust would make such stars
fainter, not brighter. Such stars are invisible because they are
just too faint by themselves. However, you might look up "Magellanic
Stream" for stars that have been tidally pulled out of the LMC and
are visible in the Sloan Digital Sky Survey.

> > > When yo look at a nebula, say the ring nebula,
> > > what is its most prominent feature, the white
> > > dwarf, or the nebula?

SW> What does this have to do with the light from galaxies?

> Visibility. You keep asking me where this gas is, and I keep
> pointing out we "only" know where the dust is that is "backlit",
> like a shadow play. So we don't even know where the *stars* are.

The Ring Nebula doesn't glow (in visible light) because of dust. In
general, gaseous nebulae aside, visible light measures where stars
are. You can do even better in the near infrared, out to wavelengths
of say 2 microns or so, but that's a minor technical point.

The basic point is that your misconception about needing dust to make
stars visible has given you the wrong idea.

> Sidelight... if we had three satellites in trojan with Earth, could
> we do VBLA techniques to achieve such resolution?

There has been satellite VLBA done from low Earth orbit. In
principle the technique should work at longer baselines, but
depending on the frequency, there may be practical limitations from
interplanetary scintillation or other effects.

[Odysseus]

In article <kollff$5l1$1...@dont-email.me>,
wil...@cfa.harvard.edu (Steve Willner) wrote:

<snip>

> In article <3311024f-acd8-463b...@googlegroups.com>,
> dlzc <dl...@cox.net> writes:

[...]

>
> > > > When yo look at a nebula, say the ring nebula,
> > > > what is its most prominent feature, the white
> > > > dwarf, or the nebula?
>
> SW> What does this have to do with the light from galaxies?
>
> > Visibility. You keep asking me where this gas is, and I keep
> > pointing out we "only" know where the dust is that is "backlit",
> > like a shadow play. So we don't even know where the *stars* are.
>
> The Ring Nebula doesn't glow (in visible light) because of dust. In
> general, gaseous nebulae aside, visible light measures where stars
> are. You can do even better in the near infrared, out to wavelengths
> of say 2 microns or so, but that's a minor technical point.

I'm not sure about the Ring, but in many planetary nebulae, and
occasionally elsewhere, the glow we see is fluorescence: X-ray and UV
emissions from very hot stars excite the surrounding gas (otherwise cool
and invisible) to re-emit down-spectrum in the visible range. Modulated
starlight, if you will, rather than simply reflected, and a little like
our own aurorae.

> The basic point is that your misconception about needing dust to make
> stars visible has given you the wrong idea.

Dust is harder to excite than gas. ;)

The interior of the vast SNR-bubble whose outer margins form the Veil
Nebula shows noticeably more stars than the surrounding area, apparently
because the region has been 'blown clear'.

--
Odysseus

[Steve Willner]

In article <odysseus1479-at-69...@news.eternal-september.org>,

Odysseus <odysseu...@yahoo-dot.ca> writes:
> I'm not sure about the Ring, but in many planetary nebulae, and
> occasionally elsewhere, the glow we see is fluorescence:

The visible glow from gaseous nebulae, including ionized hydrogen
regions such as the Orion Nebula, is indeed from the gas, not
reflected starlight. The visible light is not continuum emission at
all wavelengths but rather is concentrated in emission lines at
discrete wavelengths. (There is some continuum emission, too, but
it's weak.) The basic physical processes were worked out in the
1930s. Fluorescence is part of the story (look up "Bowen
fluorescence mechanism"), but a bigger part is collisional excitation
of ions by electrons. The hydrogen and helium lines come from
recombination.

That's in visible light. Emission processes at other wavelengths
differ. In particular, the infrared has continuum emission from
dust. This is not reflected starlight either.

There are "reflection nebulae" and a few other cases where starlight
reflected by dust is important (including the Sun's "F corona"), but
overall such cases are pretty rare.

> X-ray and UV emissions from very hot stars excite the surrounding
> gas (otherwise cool and invisible) to re-emit down-spectrum in the
> visible range.

Basically right, but UV is pretty much the whole story. There aren't
enough X-rays to do much excitation. Stellar temperatures in PN
central stars range from roughly 30000 K to upwards of 100000 K. In
H II regions, stellar temperatures can be somewhat lower, perhaps
down to 15000 K. The UV from the hot stars ionizes nearby gas, and
the various processes lead to emission from the gas.

> Modulated starlight, if you will, rather than simply reflected,
> and a little like our own aurorae.

I think the aurorae are also collisional excitation by electrons, but
the specific atoms or ions are not all the same as in ionized
nebulae.

> Dust is harder to excite than gas. ;)

Yes, in visible light. When dust absorbs visible or UV light, the
dust heats up, and warm dust radiates in the infrared. In
equilibrium, the energy in has to equal the energy out. The net
effect is converting visible or UV light to infrared, so it's the
same sort of outcome, but the physical process is different.

> The interior of the vast SNR-bubble whose outer margins form the Veil
> Nebula shows noticeably more stars than the surrounding area, apparently
> because the region has been 'blown clear'.

In general, star counts can be used to measure extinction: more
stars, less extinction. Of course you have to be sure the true
number of background stars is constant, so the method only works over
limited areas.

[Brad Guth]

On May 17, 5:44 am, David Levy <David.Levy.bdbe...@spacebanter.com>
wrote:
> I would like to get your advice with regards to the Star age
> Measurements.
>
> This is critical element for any theory. This is a key element for
> confirming the Big bang theory. Therefore, I was quite surprise to find
> that this key measurement is actually based on the Big Bang theory.
>
> Based on Wiki it is stated:
>
> "The metallicity of an astronomical object may provide an indication of
> its age. When the universe first formed, according to the Big Bang
> theory, it consisted almost entirely of hydrogen which, through
> primordial nucleosynthesis, created a sizeable proportion of helium and
> only trace amounts of lithium and beryllium and no heavier elements.
> Therefore, older stars have lower metallicities than younger stars such
> as our Sun."

>
> So the science is measuring the star age based on the fundamental Idea
> of the Big bang.

> With the results of the star age they are coming back and reconfirm the
> Big bang theory.
>

> This might be radicals and contradicts a basic common sense.
> I assume that without the big bang theory, the Science could develop
> some other method for Star age measurements.
>
> Please advice.
>
> --
> David Levy

Mainstream science and even its physics is highly dependent upon the
Big Bang, even though there's nothing objectively supporting the BB.
In other words, we get to make do with our mainstream of circular
logic instead of objective proof of anything that truly matters.

Original BB stars of perhaps at least 1000+ solar mass(2+e33 kg) and
supposedly comprised of only hydrogen that lasted at best a few years,
is where that initial hydrogen fusion process created helium and
eventually every other known element of metallicity. So, newer stars
are those of considerably lower mass (under 10 SM), as well as having
a much higher helium content and/or hosting those heavier elements of
metals as well as their having created numerous planets that by now
should far outnumber all the stars (including brown dwarfs that are
actually large gas giants with perhaps a hundred moons each)
combined. Some of us would speculate there's at least a thousandfold
as many planets as stars, and the vast majority of them planets got
created a billion years before our solar system even formed.

The rate of hydrogen fusion consumption can be used to estimate the
given age and/or lifespan of stars, although helium fusion driven
stars are entirely another issue.

[dlzc]

Dear Brad Guth:

On Tuesday, June 11, 2013 9:06:45 AM UTC-7, Brad Guth wrote:
...

> Mainstream science and even its physics is highly
> dependent upon the Big Bang, even though there's
> nothing objectively supporting the BB.

Say what?

> In other words, we get to make do with our
> mainstream of circular logic instead of objective
> proof of anything that truly matters.

We can use actual data to get us back to a few hundred million years of the CMBR. And this data without "assuming" a Big Bang, points to a much smaller Universe at that time.

Beyond this CMBR curtain, Science does not do "proof", you know this, yet you continue posturing. We have theory where we have data, and cosmology (including the Big Bang) is largely "extrapolation" at best.

Does lying include what you think "truly matters"? Please do not continue to present Science arriving at any sort of proof, or failing because it *never* can do this. Only Religion, Philosophy, and Law have proofs.

David A. Smith