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Early galaxies in formative stages: where are they now?

  1. Aug 29, 2012 #1

    PhanthomJay

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    OK , so Hubbell took a picture of an early infant galaxy as it existed 10 billion years ago or so with its light just now reaching its cameras. . We've all seen the pics. Lets call it Galaxy A. I'd like to know, where is that galaxy A now as it presently exists , 10 billion years later in the year 2012? Is it possibleto know or even predict anything about it in its present state of existence?
     
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  3. Aug 29, 2012 #2

    phinds

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    "Know". No. It is casually disconnected from us by 10 billion years, so in terms of "know", we'll always be 10 billion years late in knowing what's going on with it and of course at some point it will pass out of our observable universe due to the expansion so even that link won't last forever.

    It is LIKELY that it is now a grown-up galaxy in pretty much the same direction in which we now see it as an infant in our present and its past, just MUCH farther away.
     
  4. Aug 29, 2012 #3
    One of the principles of cosmology is that at a given time, things look more or less the same in all parts of the universe.

    So a random galaxy that you see 10 billion years ago, should today look more or less like the nearby galaxies we see today. Conversely, looking at galaxies that are 10 billion years old gives you an idea of how our galaxy looked 10 billion years ago.
     
  5. Aug 29, 2012 #4

    PhanthomJay

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    OK, thanks to both of you for the responses. I sort of anticipated this. But what's bothering me is that on the one hand, we seem to know everything about how much matter, dark, matter , and dark energy exist in the universe, in pretty exact pecentages, mind you, and yet on the other hand, we know nearly nothing about the universe as it presently exists. How do you explain this paradox?
     
  6. Aug 29, 2012 #5

    phinds

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    I don't understand why you see any paradox because I don't agree that we we know nearly nothing about the universe as it presently exists. I'd say we know quite a remarkable amount. It may not seem like much when looked back on in a thousand years, but still "nearly nothing" ??? --- I just don't get that at all.
     
  7. Aug 29, 2012 #6

    PhanthomJay

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    Well, that's what you told me, no? That we know nothing about the early galaxies in their present state, or about anything whose light has not yet reached us...heck, maybe the sun has disintegrated but we won't know that until 8 minutes from now....an unlikely occurrence for sure but do you catch my drift??
     
  8. Aug 29, 2012 #7

    phinds

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    Ah ... gotcha now. Yes, you're right. We are ASSUMING, without basis in fact but a reasonable assumption nonetheless, that the sun hasn't disintegrated and such.

    Every "new" event, a supernova say, is a surprize to us even though most of them happened before there were any humans around.

    STILL ... we know all kinds of things about what kinds of stars there are and what their life-spans look like, and just TONS of other things about how the cosmos is made up.
     
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