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Thread: Astronomers have missed 90% of galaxies

  1. #1 Astronomers have missed 90% of galaxies 
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    Astronomers have long known that many surveys of distant galaxies miss 90% of their targets, but they didn't know why. Now, astronomers have determined that a large fraction of galaxies whose light took 10 billion years to reach us have gone undiscovered. This was found with an extremely deep survey using two of the four giant 8.2-meter telescopes that make up ESO’s Very Large Telescope (VLT) and a unique custom-built filter. The survey also helped uncover some of the faintest galaxies ever found at this early stage of the Universe.


    http://www.universetoday.com/2010/03...more-universe/


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  3. #2  
    Moderator Moderator Dishmaster's Avatar
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    And the Herschel Space Observatory makes them visible at high redshift. Every single dot is a distant galaxy, all of them covering the field of view entirely.



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    Universal Mind John Galt's Avatar
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    Space is big. Really big. You just won't believe how vastly hugely mindbogglingly big it is. I mean you may think it's a long way down the road to the chemist, but that's just peanuts to space.

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    Forum Isotope Bunbury's Avatar
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    Astronomers have long known that many surveys of distant galaxies miss 90% of their targets
    How did they know this? Since they knew this already, then presumably this new information doesn't affect dark matter calculations, or does it?
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    Forum Professor Wild Cobra's Avatar
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    Quote Originally Posted by Bunbury
    Astronomers have long known that many surveys of distant galaxies miss 90% of their targets
    How did they know this? Since they knew this already, then presumably this new information doesn't affect dark matter calculations, or does it?
    On top of that, photon emission is not infinite. Once you get so far out, we simply may not get any photons that strike the finest of our equipment.
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    Quote Originally Posted by Wild Cobra
    On top of that, photon emission is not infinite.
    What do mean?
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  8. #7 My two cents 
    Forum Freshman zazzerak's Avatar
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    If you believe certain theories space is expanding with the big bang event horizon, giving space a measurable radius, around 14 billion light years, so the farthest out we could see would be galaxies 7 billion light years out.
    or if you believe the mirror box theory we're only seeing the same couple of galaxies being reflected back to us several thousand times.
    A perfect paradox
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  9. #8 Re: My two cents 
    Universal Mind John Galt's Avatar
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    Quote Originally Posted by zazzerak
    If you believe certain theories space is expanding with the big bang event horizon, giving space a measurable radius, around 14 billion light years, so the farthest out we could see would be galaxies 7 billion light years out..
    Do you want to review your understanding of the words radius and diameter?
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  10. #9 reply 
    Forum Freshman zazzerak's Avatar
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    no, I mean what I mean, supposedly the universe has a RADIUS of 14 billion light years. therefore we can only see galaxies from half that distance out.
    A perfect paradox
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  11. #10 Re: reply 
    Moderator Moderator Dishmaster's Avatar
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    Quote Originally Posted by zazzerak
    no, I mean what I mean, supposedly the universe has a RADIUS of 14 billion light years. therefore we can only see galaxies from half that distance out.
    Why? This value you quote is the radius of the visible universe. From every point in the universe, the most distant point visible is about 14 billion light years away.
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