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Thread: Let' talk of a little Astrophysics

  1. #1 Let' talk of a little Astrophysics 
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    QUESTION: QUASAR DISCOVERY

    (1 point possible)
    Imagine that you take a picture of some part of the sky and detect three "dots", each with the same apparent brightness (flux).
    You then measure the spectra of the three dots. The first shows a narrow absorption line at 656.3nm wavelength. You know that this is the wavelength of a strong hydrogen absorption line in the laboratory. The second shows the same line, but it is now a broad emission line at a wavelength of 690 nm. The third once again shows this line, but once again it is a broad emission line, now at a wavelength of 720nm.
    What can you conclude from this?


    The first object is a quasar, while the second and third are stars.
    The third object is the most luminous
    The second and third objects are quasars and have the same luminosity
    The first object is the most luminous
    The second object is the most luminous

    I am not wondering for homework, I already have answered this, just wanted to ask y'all if you know.
    I will give the professor's answer when and if y'all like.

    If you are really interested in cutting science, that is.



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  3. #2  
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    So we're back to playing school again.

    Please. Find another way to approach this if you want people here to discuss the topics raised in your course.


    exchemist likes this.
    "Courage is what it takes to stand up and speak; courage is also what it takes to sit down and listen." Winston Churchill
    "nature is like a game of Jenga; you never know which brick you pull out will cause the whole stack to collapse" Lucy Cooke
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  4. #3  
    Universal Mind John Galt's Avatar
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    Quote Originally Posted by Mayflow View Post

    If you are really interested in cutting science, that is.
    First, I suspect you meant cutting edge science. Cutting science would be to do with surgery, or drilling rock.

    Perhaps it is not intended, but their is an implicit criticism in your statement. You suggest that if we are not interested in this then we are not interested in cutting edge science. Well that would only apply if we are interested in cutting edge cosmology. I may be interested in cutting edge exoplanet investigations, or protein folding, or the geodynamo, but be left cold by cosmology.

    So, I'm not sure if you are being deliberately provocative, or just rather thoughtless. Either way it is annoying and counterproductive.

    Finally, you are mistaken if you think your questions relate to cutting edge science. I know essentially nothing about cosmology, but the only acceptable option I can see is that the "the third object is the most luminous". This was a cutting edge application (in the 1960s) of a concept that was cutting edge many decades before.

    If you wish I can detail for you why the other options are wrong.
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  5. #4  
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    EXPLANATION
    The broad emission lines and redshifts of the second and third objects indicate that they are quasars. They both have the same flux, but as the the third object has a greater redshift, it must be more luminous to give that equal observed flux.

    Now on a side note, I don't like you dissing me John. I am not here to want to be dissed, and please stop it. There are plenty others here who will do that for you
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  6. #5  
    Forum Radioactive Isotope
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    Unless "cutting science" means "understanding science" or "making the grade in science" ?

    I can't answer your questions by the way.
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  7. #6  
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    O good grief. I let the topic go away now.
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  8. #7  
    Universal Mind John Galt's Avatar
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    Quote Originally Posted by Mayflow View Post
    EXPLANATION
    The broad emission lines and redshifts of the second and third objects indicate that they are quasars. They both have the same flux, but as the the third object has a greater redshift, it must be more luminous to give that equal observed flux.
    So your Professor has given the correct answer with the correct reasoning, neatly matching the conclusions of an individual who freely admits to knowing next to nothing about cosmology and possibly having even less interest in it. I offer that as evidence that this is not cutting edge science.

    Now pay attention. The disrespect is coming from you. I have patiently explained this to you. You have implicitly criticised your readers in a provocative manner. You are the one who is being disrespectful.

    I have pointed this out to you, but instead of accepting that criticism you ignore it and attempt to reverse the position. It won't wash lass. You were rude, either through ignorance, or deliberately. Your decision not to apologise suggests it was the latter. (The third alternative explanation would be disrespectful and I prefer not to go there.)
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  9. #8  
    exchemist
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    Quote Originally Posted by Mayflow View Post
    O good grief. I let the topic go away now.
    Hooray.
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