36grit Posted March 28, 2013 Posted March 28, 2013 http://www.astronomy.com/News-Observing/News/2013/03/Hubble%20pins%20down%20age%20of%20oldest%20known%20star.aspx?utm_source=SilverpopMailing&utm_medium=email&utm_campaign=ASY_News_Sub_130315_Final&utm_content= interseting article in Astronamy magazine.
Griffon Posted March 28, 2013 Posted March 28, 2013 Science makes progress through anomolies like this. It could mean nothing more than a slight problem in our understanding of the age of stars, the universe or both. After all the error on the estimated age of the star means its lower value lies within the accepted age of the universe. On the other hand this discrepancy could point to a major problem with our understanding of cosmology. It's impossible to say with certainty where the problem lies . My hunch is that the problem lies in our understanding of how to estimate the age of stars. Whereas the time since the Big Bang has not only been studied more thoroughly but is estimated by several different methods I understand. .... though as we saw recently, the age of the universe isn't set in stone, having got 60 million years older due to the recently published new cosmic microwave background data.
michel123456 Posted March 28, 2013 Posted March 28, 2013 (edited) HD 140283 is 190 LY away, that is inside our Milky Way galaxy which is approximately 100,000 ly (30 kpc) in diameter. The oldest known star in the Universe is in our galaxy? Edited March 28, 2013 by michel123456
Griffon Posted March 28, 2013 Posted March 28, 2013 Is that a question of surprise that such is possible? It certainly is possible because such stars are thought to be first generation stars formed at the earliest times. They are very low in atoms of higher atomic mass because they were formed before supernovae generated such elements.
michel123456 Posted March 28, 2013 Posted March 28, 2013 Is that a question of surprise that such is possible? It certainly is possible because such stars are thought to be first generation stars formed at the earliest times. They are very low in atoms of higher atomic mass because they were formed before supernovae generated such elements. This is not what is presented in the wiki page: Accurate determinations of the ages of metal-poor stars, such as HD 140283, set a lower limit for the possible age of the universe.[5] Studies of the star also help astronomers understand the universe's early history. The very low but non-zero metallicity of HD 140283 is indicative of a star born in the second generation of stellar creation.[9] The first stars are thought to have been born a few hundred million years after the Big Bang, and they died in supernova explosions after only a few million years.[9] A second generation of stars, the generation in which HD-140283 is theorized to have been born, could not have coalesced until gas, heated from the supernova explosions of the earlier stars, cooled down.[9] The age of HD 140283 indicates that the time it took for the gases to cool was likely only a few tens of millions of years.[9] --------------- And certainly it is a question of surprise. I wouldn't expect such an ancient object so close to us. This star seems older than very far away galaxies.
StringJunky Posted March 28, 2013 Posted March 28, 2013 This is not what is presented in the wiki page: --------------- And certainly it is a question of surprise. I wouldn't expect such an ancient object so close to us. This star seems older than very far away galaxies. The universe is the same age everywhere so it's no surprise to me that such an old object is near us 2
Griffon Posted March 28, 2013 Posted March 28, 2013 (edited) Reply to Michel12345 Yeah, I'm saying the same thing in a different way. Distant galaxies are older, sure, because the light has taken longer to get here. So we inevitably see them as they were millions or even billions of years ago. But there's no reason why nearer things should not be older too. The universe is the same age everywhere so it's no surprise to me that such an old object is near usThat's a nice wy to put it I think. I suppose th e amazing thing is that stars have such a wide range of life durations. A few million for stars that burn bright and short. 8 billion or so years for sun-like stars, and at least as old as the universe for stars like HD140283. Edited March 28, 2013 by Griffon
StringJunky Posted March 28, 2013 Posted March 28, 2013 ...That's a nice way to put it I think. I suppose th e amazing thing is that stars have such a wide range of life durations. A few million for stars that burn bright and short. 8 billion or so years for sun-like stars, and at least as old as the universe for stars like HD140283. Yeah, even though the age is the same, what we measure is different due to the finite speed of information but one also has to be careful as there is no preferred time reference as far as I understand...it confuddles me greatly to be honest as a total novice. Stardust by John Gribbin is a nice book (and cheap) for a lay reader on the evolution of stars.
michel123456 Posted March 29, 2013 Posted March 29, 2013 (edited) Reply to Michel12345 Yeah, I'm saying the same thing in a different way. Distant galaxies are older, sure, because the light has taken longer to get here. So we inevitably see them as they were millions or even billions of years ago. But there's no reason why nearer things should not be older too. That's a nice way to put it I think. I suppose the amazing thing is that stars have such a wide range of life durations. A few million for stars that burn bright and short. 8 billion or so years for sun-like stars, and at least as old as the universe for stars like HD140283. (emphasis mine) You meant younger, relative to age zero at the Big Bang instant. What is observed in our past is ancient and thus is younger (the Greek antiquity is younger than we are, relative to the BB). What is old to us is young in the universe history. What we observe very far away are supposed to be baby galaxies. In these galaxies, it is supposed that old stars like HD140283 do not exist. Edited March 29, 2013 by michel123456
Griffon Posted March 29, 2013 Posted March 29, 2013 (edited) Those distant galaxies are old now, assuming they still exist. Presumably they now consist of many younger stars and perhaps a few older objects that date from the earliest times - much like our galaxy. There's no way of knowing of course. Edited March 29, 2013 by Griffon
StringJunky Posted March 29, 2013 Posted March 29, 2013 I think this might be the actual paper: http://hubblesite.org/pubinfo/pdf/2013/08/pdf.pdf 1
Arch2008 Posted March 29, 2013 Posted March 29, 2013 It is not possible to image individual stars in other galaxies unless they explode. So this is just the oldest star that can be imaged in the universe. The article explains how the star has an unusually low metallicity. This refers to the fact that its observed light spectrum displays the signature of fewer elements heavier than hydrogen. Normally, first generation giant stars fuse hydrogen into all the other elements during their lifetime and when they explode. The shock wave disperses these elements into the surrounding cloud of hydrogen and may even contribute to the collapse of this gas into stars like our Sun. This particular star was likely formed in a dwarf galaxy that was then torn apart as it approached the Milky Way. It may just be that this dwarf galaxy did not have enough mass for the statistically average number of first generation stars to form. So the lack of first generation stars gave this star fewer heavier elements in its make-up. No star can be older than the universe.
ydoaPs Posted March 29, 2013 Posted March 29, 2013 http://www.astronomy.com/News-Observing/News/2013/03/Hubble pins down age of oldest known star.aspx?utm_source=SilverpopMailing&utm_medium=email&utm_campaign=ASY_News_Sub_130315_Final&utm_content= interseting article in Astronamy magazine. I'm not seeing how the conclusion "star older than the universe" follows from the data. The date ranges overlap.
Griffon Posted March 29, 2013 Posted March 29, 2013 (edited) Might this imply that the star is not old at all? It just formed in an environment that had a low metalicity? [Response to Arch2008's post] Edited March 29, 2013 by Griffon
Arch2008 Posted March 29, 2013 Posted March 29, 2013 http://www.eso.org/public/archives/releases/sciencepapers/eso1007/eso1007.pdf Gotta run.
Iggy Posted April 7, 2013 Posted April 7, 2013 (edited) Might this imply that the star is not old at all? It just formed in an environment that had a low metalicity? [Response to Arch2008's post] There is no doubt that it formed in an area of low metallicity. The age doesn't just come from the metallicity though. The metallicity and mass let you predict what line the star should follow on an HR diagram. Where exactly it is on that line (determined by its brightness and color) then says how old it is. edit: in theory ;-) Edited April 7, 2013 by Iggy
liver Posted April 8, 2013 Posted April 8, 2013 (edited) where would such an old, long-lived star get the energy, mass to continue to radiate? should we not exploit that to keep our star and us from premature old age? Edited April 8, 2013 by liver
Iggy Posted April 9, 2013 Posted April 9, 2013 (edited) More massive stars live shorter lives. A very small star can easily radiate for a trillion years. Our sun, believe it or not, doesn't generate much energy per volume. Deep in the sun if you looked at a hundred kilograms of hydrogen being fused into helium at the rate it's happening, the heat created is actually less than the heat a hundred kilogram person creates just walking around every day. The enormous energy radiated by the sun is a result of its enormous size. Edited April 9, 2013 by Iggy
michel123456 Posted April 9, 2013 Posted April 9, 2013 More massive stars live shorter lives. A very small star can easily radiate for a trillion years. Our sun, believe it or not, doesn't generate much energy per volume. Deep in the sun if you looked at a hundred kilograms of hydrogen being fused into helium at the rate it's happening, the heat created is actually less than the heat a hundred kilogram person creates just walking around every day. The enormous energy radiated by the sun is a result of its enormous size. ? I used to imagine the sun core as a furnace.
Iggy Posted April 9, 2013 Posted April 9, 2013 ? I used to imagine the sun core as a furnace. They both create heat. What is your question. There was a question mark there.
michel123456 Posted April 9, 2013 Posted April 9, 2013 They both create heat. What is your question. There was a question mark there. You are describing the heat produced by 100kgs of hydrogen fused in helium inside the Sun as corresponding to "the heat a hundred kilogram person creates just walking around every day". It is a nuclear reaction though. How come that the produced heat is so low? Or How come that the produced heat is so high when Iggy walks around?
Iggy Posted April 9, 2013 Posted April 9, 2013 (edited) You are describing the heat produced by 100kgs of hydrogen fused in helium inside the Sun as corresponding to "the heat a hundred kilogram person creates just walking around every day". It is a nuclear reaction though. How come that the produced heat is so low? Or How come that the produced heat is so high when Iggy walks around? Oh, ok... Iggy is damn hot! No, I think you're wanting me to confirm what I said... let me find a source... At the center of the Sun, theoretical models estimate it to be approximately 276.5 watts/m3,[54] a power production density that more nearly approximates reptile metabolism than a thermonuclear bomb. wikipedia -- sun -- core There we go. Wikipedia never fails to impress. So, I'm a bit hotter than a reptile, can we agree? edit... You ask how come the heat produced is so low. Well, it is just what it is. At that pressure under that gravity the exact fusion that takes place is compatible to the human metabolism. It is perhaps surprising, but it shouldn't be. Fusion is, after all, a difficult thing to accomplish. Edited April 9, 2013 by Iggy
zapatos Posted April 9, 2013 Posted April 9, 2013 Oh, ok... Iggy is damn hot!So if I read that correctly, the hundred kilograms of Hydrogen you mentioned generates so little heat because it will take billions of years (or some other large time frame)for it to completely fuse into Helium. Did I get that right?
Iggy Posted April 9, 2013 Posted April 9, 2013 So if I read that correctly, the hundred kilograms of Hydrogen you mentioned generates so little heat because it will take billions of years (or some other large time frame)for it to completely fuse into Helium. Did I get that right? Yes, I definitely agree.
michel123456 Posted April 9, 2013 Posted April 9, 2013 Oh, ok... Iggy is damn hot! No, I think you're wanting me to confirm what I said... let me find a source... wikipedia -- sun -- core There we go. Wikipedia never fails to impress. So, I'm a bit hotter than a reptile, can we agree? edit... You ask how come the heat produced is so low. Well, it is just what it is. At that pressure under that gravity the exact fusion that takes place is compatible to the human metabolism. It is perhaps surprising, but it shouldn't be. Fusion is, after all, a difficult thing to accomplish. I find that hard to believe. Checking Wiki source here, mentioning "Computer Model of the Sun at 4.5 Billion Years" from a 1965 book (B. Stromgrew (1965) reprinted in D. Clayton Principles of Stellar Evolution and Nucleosynthesis. New York: McGraw-Hill, 1968. There must be something more recent to double check.
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