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Thread: Why are so different the galaxies of the HUDF picture?

  1. #1 Why are so different the galaxies of the HUDF picture? 
    Universe Supervisor dapifo's Avatar
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    Why are so different (color, form, ....) the galaxies of the HUDF picture annexed?

    It looks more as an artistic picture than a real one !!!


    Attachment 1055


    "If everyone is thinking alike, then somebody isn't thinking". George S. Patton
    "Science does not know its debt to imagination". Ralph Waldo Emerson

    "Why settle with the known models and patterns (but not underlying laws) of Our Universe , if we might understand them better if we could puzzle out them from outside its limits?"
    (The common sense)
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  3. #2  
    Average Human guymillion's Avatar
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    Maybe this is what you are looking for:
    Types of Galaxies


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  4. #3  
    Universe Supervisor dapifo's Avatar
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    Quote Originally Posted by guymillion View Post
    Maybe this is what you are looking for:
    Types of Galaxies
    Very interesting web and pictures...

    But what I mean is that....the galaxies of the HUDF picture are very young (less than 1 billions year old)....then I though that they must be more similar....just because this...they are very young and mainly composed of Hydrgen and Helium....(?)

    And in the picture we see very different forms (spiral, ...) and colors (white, yellow, red,...)...as if they were older.

    And also...if the universe is expanding isotropically...then we could see the same type and quantity of galaxies in all the directions...isnīt it? ...and if this picture is only an 1% of the moon surface...it seams that there are more young and far away galaxies that older and nearer (??)
    "If everyone is thinking alike, then somebody isn't thinking". George S. Patton
    "Science does not know its debt to imagination". Ralph Waldo Emerson

    "Why settle with the known models and patterns (but not underlying laws) of Our Universe , if we might understand them better if we could puzzle out them from outside its limits?"
    (The common sense)
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    Quagma SpeedFreek's Avatar
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    Quote Originally Posted by dapifo View Post
    But what I mean is that....the galaxies of the HUDF picture are very young (less than 1 billions year old)
    No, only some of them are that young. The HUDF has galaxies from z=2 upwards, making some of them more than 3 billion years old.

    Quote Originally Posted by dapifo View Post
    And also...if the universe is expanding isotropically...then we could see the same type and quantity of galaxies in all the directions...isnīt it?
    Yes. When looking at a small area of the sky where there are no "close" galaxies, like we did with the HUDF.

    Quote Originally Posted by dapifo View Post
    ...and if this picture is only an 1% of the moon surface...it seams that there are more young and far away galaxies than older and nearer (??)
    Of course. Everything was closer together back then.
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  6. #5  
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    The picture has been "artistically enhanced".
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  7. #6  
    Universe Supervisor dapifo's Avatar
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    Quote Originally Posted by gonzales56 View Post
    The picture has been "artistically enhanced".
    Do you mean that colors and some forms are not the original.

    Eg. The "object like an star with four tips"?....
    "If everyone is thinking alike, then somebody isn't thinking". George S. Patton
    "Science does not know its debt to imagination". Ralph Waldo Emerson

    "Why settle with the known models and patterns (but not underlying laws) of Our Universe , if we might understand them better if we could puzzle out them from outside its limits?"
    (The common sense)
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  8. #7  
    Quagma SpeedFreek's Avatar
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    The stars with "4 tips" are foreground stars in our own galaxy. Everything else is as it was detected, using different filters on different kinds of objects to enhance (but not make up!) their colours.
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  9. #8  
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    Quote Originally Posted by dapifo View Post
    Quote Originally Posted by gonzales56 View Post
    The picture has been "artistically enhanced".
    Do you mean that colors and some forms are not the original.

    Eg. The "object like an star with four tips"?....

    Nasa freely admits that most of their images used (especially those for media, books and publications) are equal parts art and science. One will have to look at individual pictures and find out exactly how they were artistically enhanced and modified, if at all, in order to know what was done to the image.
    Last edited by gonzales56; September 4th, 2012 at 02:07 AM.
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  10. #9  
    Quagma SpeedFreek's Avatar
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    Is it "art" when we detect wavelengths that aren't visible to the human eye, and give them a colour so we can see them?

    Those pictures contain data from x-ray detectors and infra-red detectors, which are given colours to make them visible.

    They never put something where there is nothing.

    Unless, that is, you are talking about "artists impressions", but the HUDF is not an atrists impression, it is a photograph, taken over many months, using various different instruments, which has been combined to make a final image, and some colours have been enhanced to make them visible.
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