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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. |
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Star age Measurements
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) |
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Thanks Mike
Quote:
If so, then a star age should not be measured based on its metallicities composition. Therefore, how do we currently estimate a star age? Quote:
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? Last edited by David Levy : May 18th 13 at 03:51 PM. |
#4
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Star age Measurements
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 |
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Star age Measurements
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 |
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Star age Measurements
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) |
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Star age Measurements
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 |
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Star age Measurements
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) |
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Star age Measurements
In article ,
"Mike Dworetsky" 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...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. You've almost certainly seen it befo 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 |
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Star age Measurements
On May 20, 2:45*am, Odysseus wrote:
In article , *"Mike Dworetsky" 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...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. You've almost certainly seen it befo 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/astron...es/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 ?. |
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