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I Oldest galaxy to date: UDFy-38135539

  1. Apr 24, 2017 #1
    Ok... so the furthest galaxy (Object: UDFy-38135539) to date has been found by the Hubble Ultra Deep Field cameras which to date goes back some 13.1 billions light years (conservative universe estimate is 13.7 billion light years) so pretty much an object with many questions. See: https://www.newscientist.com/article/dn19603-dim-galaxy-is-most-distant-object-yet-found/

    My question should a supernovae happen to any massive star in this old system, would the energy/particles of the supernovae push the outer edges of the universe in a 'bump' like state in that region or would the outer edge of the universe absorb this energy or expand further due to this event? Curious.
     
  2. jcsd
  3. Apr 24, 2017 #2

    PeterDonis

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    The universe does not have any edges, so I don't know what to make of your question.
     
  4. Apr 24, 2017 #3
    Understand it's a void... so in other words the energy of the supernovae would just travel out to nothingness past the oldest objects known?
     
  5. Apr 24, 2017 #4

    PeterDonis

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    What is a void? The universe does not become a void past a certain distance from us. It has matter everywhere.
     
  6. Apr 24, 2017 #5

    Bandersnatch

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    No, it's not a void. It's just more of the same as everywhere else - more or less uniformly filled with matter.
     
  7. Apr 24, 2017 #6
    Perhaps I worded it incorrectly... 'Void' meaning there are no stars, universes, etc... perhaps dark matter/hydrogen mist from the early days formation of the universe and objects we have yet to discover. We're talking 13.7 billion years point... something we have yet to detect.
     
  8. Apr 24, 2017 #7

    PeterDonis

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    That is not the case. There are more objects from the early universe that we haven't seen yet, because the universe has a finite age. As time goes on, more objects from the early universe will come into view, ones that were further away from us in the early universe and whose light therefore will take longer to reach us. If our current best fit model of the universe is correct, the universe is spatially infinite, so we will continue to see new objects from the early universe as time goes on, forever (or at least as long as we are here to keep looking).
     
  9. Apr 24, 2017 #8
  10. Apr 24, 2017 #9

    PeterDonis

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    Do you mean towards the Big Bang? No, of course not; that would mean the energy would be going backwards in time.
     
  11. Apr 24, 2017 #10
    Agree... our only drawback then is our technology to view and or capture this light from the early beginning of time.
     
  12. Apr 24, 2017 #11
    But wouldn't the light seen 13.7 billion light years be the oldest light known more or less if we could detect it? So this energy from the GN-z11 supernova (or older galaxy) would be approaching this 'older light' perhaps or surpass it theoretically?
     
  13. Apr 24, 2017 #12

    PeterDonis

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    At this moment, yes. But next year we could, in principle, see light that took 1 year longer to get to us (and is therefore one year older), because it was emitted from a point a bit further away (much less than 1 light-year, because the universe has expanded since then by a very large factor).

    A beam of light cannot catch up with another beam moving in the same direction that was emitted ahead of it.
     
  14. Apr 24, 2017 #13
    upload_2017-4-24_12-55-52.png

    So in this image I created the supernova's light would be emitted towards the older region of space which of course is almost void of nothing but space... closer to light from the early system although everything is expanding.
     
  15. Apr 24, 2017 #14

    PeterDonis

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    No. The horizontal dimension in that drawing is time, not space. To do what you are describing, the supernova's light would need to go backwards in time. See my post #9.
     
  16. Apr 24, 2017 #15

    Drakkith

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    The key idea here is that the universe is not expanding away from a point and towards empty space (or "void" or any other term commonly thrown around). To the best of our knowledge, there is no boundary, no edge, and no "outside" to the universe. If you were able to magically teleport yourself 47 billion light years away, right to the edge of the observable universe (notice the word observable) you would look around and see galaxies and stars in every direction, just like we do here.

    There is no direction you could travel that would take you closer to the big bang. That would require time travel into the past.

    See this excellent page on cosmology: http://www.astro.ucla.edu/~wright/cosmology_faq.html#XIN (and feel free to browse through the rest of the site)
     
  17. Apr 25, 2017 #16

    Chronos

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    Recession velocity is not linear. Imagine an asteroid receding at .99c wrt an observer, and a rocket launched with a velocity of .99c wrt the asteroid in the direction opposing the observer. What is its apparent recession velocity wrt to the observer [hint: not 1.98c]. You have precisely this situation with supernova ejecta in a distant galaxy. A little SR goes a long way in this universe.
     
  18. Apr 25, 2017 #17
    (Ignoring the mistakes in terms of terminology) •••
    Yes, it would accelarate the universe expansion into 'nothingness'. As we know, the universe started expanding from a big bang in the first place, I don't see why that would not add to the expansion, provided that we agree that all we can say about the ends of the universe is limited in certainty and facts...
     
  19. Apr 25, 2017 #18

    Drakkith

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    This is incorrect. The universe is not expanding into anything or 'nothingness'.
     
  20. Apr 25, 2017 #19
    Pehraps we can argue semantics, but I am not sure if you are claiming that the universe is static and it is not expanding/stretching. In case you are, I would ask evidence from you. As for my claims that yes it is indeed 'stretching' or moving further away from it's centre (if it has one), there are numerous of studies suggesting it. For example, Riess won the Nobel prize in 2011 for discovering that the expansion of universe is in fact speeding up. So, by all means, I would love to see some evidence as I provided some myself.
     
  21. Apr 25, 2017 #20

    PeterDonis

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    It doesn't. The expansion of the universe does not mean anything is "stretching" or moving away from a center. It just means galaxies are moving apart.
     
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