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Why are we now?

  1. Nov 25, 2014 #1
    The question "what was before the Big Bang" is usely answered with the explanation that time was created along with the universe during the Big Bang, and therefor the question is meaningless. I think it is possible tho refrase the question so it 'll become a valid (meaningfull) question; why are we now (at this moment in time)? Why are we not 10 billion years or 20 billion years after the Big Bang?
     
    Last edited by a moderator: Nov 25, 2014
  2. jcsd
  3. Nov 25, 2014 #2

    berkeman

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    Thread closed for Moderation...
     
  4. Nov 25, 2014 #3

    Dale

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    The thread is reopened, please keep it on science and not philosophy or personal attitudes towards cosmology.
     
  5. Nov 25, 2014 #4

    Dale

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    One reason is that the first generation of stars needed to expire so that the heavier atoms could be synthesized.
     
  6. Nov 25, 2014 #5

    phinds

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    I'd ask it the other way 'round ... why NOT now? What objection do you have to existence as it is? I mean, is there some reason you think it should be something else?
     
  7. Nov 25, 2014 #6
    Hey, don't be so certain about when we are. It could be the middle of last month, for all we know.
     
  8. Nov 26, 2014 #7

    Chronos

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    That question has actually been posed. Physicist Robert Dicke proposed in 1961 that the age of the universe, as perceived by living observers [us], must be constrained by biological factors to be in a 'golden age,' neither too young nor too old. This was characterized as 'The Goldilocks Enigma' in a 2009 book by cosmologist Paul Davies. Some would characterize this as a rather extreme example of anthropocentrism, but, the idea has been considered by mainstream science.
     
  9. Nov 26, 2014 #8
    A good question, but the bare question may suggest simultaneity.

    If you ask "Why here?", you might consider that "here" can be relatively anywhere depending on another observer's frame of reference.
    If you ask "Why this speed?", you might consider that it could be 0 to almost c (in SR) and anything/undefined (?) in GR, depending on another observer's frame of reference..
    If you ask "Why now?", I wonder what the range of extreme time variance is with respect to the Andromeda paradox depending on another observer's frame of reference..

    Of course, these just set the stage for loosening up the "here now" idea, but emphasizing the "here" part as local, the fundamental question remains... why is there just one local time... which is to ask why is there just one local time at a time... which might be to ask why our experience is of a point on our world line rather than a segment or all of our world line.

    Maybe this question can be reformulated in a way that is more inviting to a physics answer without losing the real sense of the question?
     
  10. Dec 3, 2014 #9
    If the universe lived before; were we there?
    If the universe lives in the future; will we be there?

    Just some interesting questions to ponder :)
     
  11. Dec 4, 2014 #10
  12. Dec 6, 2014 #11
    I suppose it depends on how deterministic one chooses to be. It has been said that Columbus didn't discover America, 3 and 4 masted sailing vessels did. This assumes that once the means exists (and a means that is economically viable among other concerns) given a perceived need it was only a matter of time before someone did it. Similarly the first image was beamed into a florescent screen in an evacuated tube in 1869, so in theory, all the basic components of a TV receiver were available. That it took over 50 years before the first rudimentary TV demonstrations to occur just speaks to the fact that ALL contributing factors must be in place before a tipping point is reached.

    Dale Spam pointed out that life as we know it depends on the death of 1st generation stars, somewhat analogous to most mammals depending on the extinction of dinosaurs.

    As it applies to human mammals, there is some DNA evidence that seems to reveal that there was either a catastrophic bottleneck or a very long, gradual bottleneck (as much as 100,000 years) when human population hovered around 1000-2000 total individuals. In this state of rather extreme vulnerability, it's safe to assume that some catastrophe, even one beginning with merely an ill-advised tribal decision, let alone some large event like volcanoes or extended drought, could have wiped us out. Likely some other species would have filled the gap then, but "we" as we know it wouldn't be here.

    Since the Nuclear Age, and here I do NOT mean nuclear generated power but only explosive weapons (and not to diminish the threat of biological weapons), many scientists including Carl Sagan and Stephen Hawking, have pondered whether our ancient instincts are capable of surviving advancing technology, something like placing a loaded .357 Magnum with a hair trigger in a babies crib.

    That said, it seems there is no greater threat than ourselves for some billion years, so if we can rise above that, it's rather impossible to guesstimate how long humankind could continue to exist. There is an upper limit of course which is the ultimate demise of The Universe and who can possibly imagine what we will have learned in 1,000 years, let alone 1,000,000,000 years.... and will "we" still be recognizable by "us" today? Yes, it is interesting to ponder.
     
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