Star age Measurements

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 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)

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?

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

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.

--
Mike Dworetsky

(Remove pants sp*mbl*ck to reply)

On May 19, 9:40*am, "Mike Dworetsky"
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...010/02/461.jpg

oriel36 wrote:
On May 19, 9:40 am, "Mike Dworetsky"
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...010/02/461.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.

--
Mike Dworetsky

(Remove pants sp*mbl*ck to reply)

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/a...#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".

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 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/a...#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.


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.

--
Mike Dworetsky

(Remove pants sp*mbl*ck to reply)

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/...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-ast...dentified.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