Did metals on earth, formed on earth? or around our sun? or somewhere else?

Discussion in 'Astronomy, Exobiology, & Cosmology' started by Shadow1, Sep 2, 2010.

  1. Pinwheel Banned Banned

    Messages:
    2,424
    As I understand it most elements up to Iron were formed in stars, Iron being the most stable atom, so not suprising its pretty abundant. But the heavier atoms (less stable than iron) needed more energy than is present in most stars to be created. So it usually took something big like a supernova to create heavier elements. Cosmos is interesting, but there was an awesome (and more up to date) 3-part BBC documentary called 'Atom' which i can highly recommend which explored this idea.

    http://www.youtube.com/watch?v=sf5kMIeUhDs
    http://www.youtube.com/watch?v=cAonRoEOI1Y
     
    Last edited: Sep 4, 2010
  2. Google AdSense Guest Advertisement



    to hide all adverts.
  3. Terry Giblin Banned Banned

    Messages:
    111
    Dear Pinwheel,

    Thanks for the links, I found this one of atom really interesting, it explains so much.

    I wish I had know more about Sir Fred Hoyle life sooner, it answers a lot of questions and explains a lot of current issues in live.

    Galaxies are moving apart and there is a cosmic back ground radiation, so there must have been a 'big bang'..... How much 'proof' and 'evidence' do you need, we are scientists.

    Light in, Light out.

    Terry Giblin
     
  4. Google AdSense Guest Advertisement



    to hide all adverts.
  5. Dinosaur Rational Skeptic Valued Senior Member

    Messages:
    4,884
    James R. Do you have some reason for the following statement?
    I always thought it was a generation 3-4 or more star. While I think my opinion has merit, I do not remember reading any authoritative source on this issue.
     
  6. Google AdSense Guest Advertisement



    to hide all adverts.
  7. nietzschefan Thread Killer Valued Senior Member

    Messages:
    7,721
    It's gen 3
     
  8. prometheus viva voce! Registered Senior Member

    Messages:
    2,045

    Please Register or Log in to view the hidden image!

     
  9. Green Destiny Banned Banned

    Messages:
    1,211
    That picture seems very popular here.
     
  10. Terry Giblin Banned Banned

    Messages:
    111
    Don't Panic

    Do you not know why Patrick Stewart (Captain Picard) was made captain of the USS Enterprise?

    He grow up in Jarrow.
     
  11. Billy T Use Sugar Cane Alcohol car Fuel Valued Senior Member

    Messages:
    23,198
    To James R, Dinosaur & nietzschefan:

    One must be careful when speaking of a star’s generation as astronomers order the generations in reverse order compared to normal order of your ancestors. I.e. For them the oldest, first to exist, stars are 3d generation and clearly distinguished from later generations such as 2nd and first generation by their lack of metallic content. BTW when an astronomer speaks of “metallic content” he probably is not speaking of what most call metals but things like carbon, nitrogen and oxygen.

    In 2nd generation stars these light elements have much greater concentrations than in the original, 3d generation stars. These lighter elements also have much higher concentrations than post iron elements in the 2nd generation stars, so in spectrographic analysis, strong lines of these elements (in second or higher ionization stages, I think) are the main indicators that the star is not a 3d generation star.

    Note the lighter elements in a typical 2nd gen star were produced in the original 3d generation stars in their later stages of fusion, near the every end of their life. For example in those big 3d gen stars at one late stage the fusion was making carbon; however these later fusion stages are passed thru relatively quickly compared to the H to He fusion stage as the temperatures are much hotter. (I don’t know the actual numbers, and it would depend up the star's mass, but I would guess that typically 85% of the star’s life, prior to super nova, is spent fusing H to He.) Thus, most of the 3d generation stars are seen* while they are “non-metalic.”

    PS If you had some way to know that a star with "metalic content" was actually an original 3d generation star but seen in the last stages of its life, you could predict it would soon go supernova (but "soon" might be 50,000 years from now)

    ---------------------
    *If by "seen" one means "seen now by us" then because these 3d gen stars are old (many have already exploded in supernova) probably some thing like a 1/3 of all currently visible 3d gen stars are now in the later fusion stages (but in most cases, their metalic stage light has not yet arrived at Earth. I.e. we are seeing them as they were when younger and metal free.)
     
    Last edited by a moderator: Sep 5, 2010
  12. John Connellan Valued Senior Member

    Messages:
    3,636


    I didn't know C, N and O were metals! :bugeye:
     
  13. Billy T Use Sugar Cane Alcohol car Fuel Valued Senior Member

    Messages:
    23,198
    They are, but only for astronomers.

    There are several definitions of metal in use. One common one is that they are good conductors of heat (but none, not even gold or silver, is as good as diamond, which most do not want to call a metal.) Another is that they have free electrons in a "conduction band.*" Another is that they are exceptionally ductile. etc. for others.

    *The part I made bold of this definition is needed if you want to exclude plasmas as plasmas also have free electrons and can be better conductors than copper, etc.
     
    Last edited by a moderator: Sep 5, 2010
  14. John Connellan Valued Senior Member

    Messages:
    3,636
    Why? How does the definition of metal differ for astronomers?
     
  15. Billy T Use Sugar Cane Alcohol car Fuel Valued Senior Member

    Messages:
    23,198
    Why? -Tradition, or perhaps fact that there are two types of stars seen in the heavens - Those with few spectral lines as they are mainly H & He and both are fully ionized and the other stars, which have spectral line radiation from only partially ionized elements like carbon, etc. and perhaps iron.

    I.e. there are in the heavens two types of stars so need two names for these two classes - they chose metalic and non-metalic as their names.


    I think the reason why the recently born stars are called the first generation instead of the much older original stars is that many stars were seen and named before the telescope was invented. Then, with it a whole new set of stars was known to exist - I.e. there was the first seen set and then the second seen set visible with telescopes.

    Later with bigger telescopes and spectrographs analyzing their light a third set of very distant (and thus old) stars was discovered*. So astronomers called the first known stars the first generation, and the distant old stars the 3d generation, but on a time scale the 3d generation were bon and many died long before what is called the 1st generation.

    *We are in most 3d generation cases looking at the light from stars that no longer exist. If those who think the universe was created by God about 6000 YBP then their God is a very dishonest God as he made the starlight we see appear to be coming from stars that he never made.
     
    Last edited by a moderator: Sep 5, 2010
  16. James R Just this guy, you know? Staff Member

    Messages:
    32,549
    Looks like I was a bit careless and made a few mistakes. Thanks to everybody who has provided corrections.
     
  17. Dinosaur Rational Skeptic Valued Senior Member

    Messages:
    4,884
    Generations, as used by astronomers, puts Sol in the first generation along with all stars which could be seen with the naked eye & primitive telescopes. Id est: First generation are those first seen by humans. Second generation are those that could be seen with much better late 19th & early 20th century telescopes. Third generation being the rest. At least that is my interpretation of some previous posts.

    Since the intent of this Thread relates to the creation of metals, the astronomer term does not seem correct.

    Suppose we use the term stage. First stage stars were the first to exist & were almost entirely composed of hydrogen & helium. Second stage stars were formed from interstellar gas & dust produced when first stage stars went nova or supernova. Third stage stars were formed from gas & dust produced by second stage stars, et cetera. Each stage has more elements other than hydogen/helium.

    It might be almost impossible to be certain of the stage of a star, with analysis of the ratio of hydrogen/helium to other elements providing the basis for making estimates.

    On the basis of the above definition, I am certain that Sol is at least second generation & might be 4-6th. Sol is far from galactic center where there was a lot of early star formation. Some of those early stars were massive & short-lived (well less than one billion years).

    Sol was formed a bit less than 5 billion years ago. Assuming the first stage stars formed about one billion years (or less) after the big bang (a guess by me), that leaves some what more than 7 billion years between the first stage stars & Sol. Third or fourth stage for Sol seems likely, although perhaps it could be fifth stage. My intuition says third stage is less likely than fourth, but this is only a guess.

    I did a bit of searching, but did not find any sources which seemed credible.

    Does anyone here know of a credible authority on this issue?
     
  18. Billy T Use Sugar Cane Alcohol car Fuel Valued Senior Member

    Messages:
    23,198
    Dinosaurs' post 34 is useful restatement of post 28 with the introduction of the term "stage," but may mislead one to think there are separated stages. The life expectancy of a star depends mainly on its mass. Thus some smaller "1st stage" were still existing when "3d stage" stars were. I.e. "stage" is a way to avoid the confusion astronomers created with their backwards use of "generations" but it must be understood that stages overlap in time and are not sequential.
     
  19. Walter L. Wagner Cosmic Truth Seeker Valued Senior Member

    Messages:
    2,555
    Astronomers ususally refer to the 'metallicity' of a star, i.e. what percentage of the star's outer gas is metallic ions (and therefore formed from prior supernova ejecta), as opposed the primoral materials of H and He. High metallicity stars are presumed 3rd or 4th stage. I am unfamiliar with any that are believed to be 5th or 6th stage as implied by Dinosaur's post.
     
  20. Shadow1 Valued Senior Member

    Messages:
    4,160
    .

    ah ok, thanks for the link
     
  21. Shadow1 Valued Senior Member

    Messages:
    4,160
    .

    thanks everyone, that was very helpfull
     
  22. Fraggle Rocker Staff Member

    Messages:
    24,690
    I don't have my copious notes on this computer, but, IIRC, macrocosmologists call all elements below the first row on the periodic table "metals." The reason for this is that when you look at a pie chart of the composition of the universe, the large sectors are dark matter, dark energy, etc. Eventually you get down to hydrogen and helium, which comprise such a narrow sector that you can't write in it and it has to be labeled with a balloon. All other elements combined are such a tiny fraction of the "stuff" in the universe that they're almost irrelevant--except to folks like us who happen to be made out of them! Like I said I haven't got the figures with me, but it's something like one hundredth of a percent.

    To call these "metals" when that word already means something... well as I have remarked rather often on this website, scientists do a perfectly rotten job of communicating with laymen. It's like they consider science a medieval guild craft and they actually don't want outsiders to understand it!
     
  23. Billy T Use Sugar Cane Alcohol car Fuel Valued Senior Member

    Messages:
    23,198
    To Fraggle: I agree with your post. I named three, C, N, O "metals" as for astronomers they are among the most common "metals." I said "such as" before naming them as you are correct, for astronomers, everything but H & He is a metal.
     

Share This Page