Will man ever reach the end of the universe?

Discussion in 'Astronomy, Exobiology, & Cosmology' started by A Canadian, Jan 27, 2003.

  1. Beercules Registered Senior Member

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    Re: By the time we get there it will have moved.

    Even if the universe were to stop expanding and become static somehow, there would still be no edge or center. Just as there is no edge to the surface of the earth, there is no end of the universe.
     
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  3. Persol I am the great and mighty Zo. Registered Senior Member

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    So eventually while travelling in one direction you end up at the same place? See the infinite light paradox above.
     
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  5. Beercules Registered Senior Member

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    If the universe is finite, then yes you would. This does not create a paradox, since the speed of light is finite and so is the age of the universe.
     
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  7. apolo Registered Senior Member

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    Reply to pesol

    An infinite number of stars does not mean light all over the sky because obviously most of them are too far away from us to see them.
    I thought that old conundrum had been solved years ago by someone much more famous than me.
    Here is an experiment you can do. Take a look at a picture of the sky taken by one of the giant telescopes (in a book or the internet) and you will see a multitude of bright stars and galaxies,some of them even fairly close together.
    Now let us assume that picture was takin of that portion of the sky that lies betveen the 2 stars marking the shoulders of orion.
    Then you go outside and look at orion, you will see no stars between the 2 shoulder stars. Where has all the stars gone? They are obviously too far away and too faint to be seen with the naked eye.

    Regards M.J.
     
  8. Persol I am the great and mighty Zo. Registered Senior Member

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    but a small fraction of that light gets to us from each star... just not enough to see... if you have an infinite number of stars every direction will have an infinite number of stars. Add up all the light from all the stars and you'd have visible light.

    I know this is not the case.... which is why I think that there is a finite amount of filled space.
     
  9. Tallguy That's the way it is... Registered Senior Member

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    Just curious, I've heard the speed of light in Miles per Hour Is approx. 640,000,000 MPH; Is that right?
     
  10. Beercules Registered Senior Member

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    Re: No end to the universe? Analogy to spherical earth.

    Fraggle Rocker,

    Yes, the analogy of the 2D surface of the earth has it's shortcomings. The universe would be the 3D equivalent of a curved surface, which we cannot imagine since we only see things in 3 dimensions. Such a closed universe is a prediction of general relativity for finite universes. For some reason, a normal sphere (or non hyperbolic) shape is not even an option.
     
  11. Beercules Registered Senior Member

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    Speed of light

    The speed is 186,000 miles per second, so yeah you're close.
     
  12. A Canadian Why talk? When you can listen? Registered Senior Member

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    #1 star are spread out so there "space" inbetween them (thus the darkness)
    #2 its possible that the universe is so big that even somes stars light havnt even reached earths view yet, or mabey a big planet is blocking them


    BTW ever hear of blinking stars, when a planet covers the star with its orbit and viewing them from earth it looks like they are winking at you

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    but still if we are in a loop in the universe, like there being no edge of the earth, then that means there has to be something outside of it....

    mabey we live in a multiverse!
     
  13. Fraggle Rocker Staff Member

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    Speed of light

    It's a lot cooler in metric: 3*10^8 m/sec
     
  14. Beercules Registered Senior Member

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    342
    Logically, there doesn't need to be an outside. Unless someone has a found reason, but isn't sharing it with us.
     
  15. Fraggle Rocker Staff Member

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    24,690
    Fractal geometry

    No. That's the whole thing about using fractals and saying that the universe has 4.2 dimensions. The .2 accounts for the curvature and nothing more. It does NOT imply that there is another whole dimension in which the universe extends to infinity. (The ".2" is certified arm-waving, I have no idea how they "count" partial dimensions. A fractal specialist I am not.)
    Hey, wasn't that a great book by James P. Hogan? Or am I thinking of "Entoverse"? One of his finest, and they're all good.
     
  16. RDT2 Registered Senior Member

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    460
    Re: Fractal geometry

    No - the surface of a sphere, for example, is exactly 2-D, it's not a fractal. The non-integer part of a fractal's dimension arises because of its 'jaggedness', not its curvature. The surface of the Earth, with its irregularities, could be assigned a fractal dimension but it would be very close to 2.

    By measuring the slope of a Richardson plot - basically a graph of, for example, the length of a coastline versus the length of the 'measuring stick' being used.

    I am.

    Cheers,

    Ron.
     
  17. Persol I am the great and mighty Zo. Registered Senior Member

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    The big planet blocking them doesn't work... because even if you block a portion of infinity you are still left with infinity. The speed of light problem is an interesting one which I hadn't thought of. It argues with the big-ban theory though. There's probably other ways around the infinite light problem.
    I call them satalites

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    j/k
     
  18. Beercules Registered Senior Member

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    I don't know why Olber's paradox is still being discussed. The fact the universe is of finite age, and expanding means we will only ever be able to see a finite amount of starlight. The paradox is thus resolved with the big bang, even in an infinite universe.
     
  19. Persol I am the great and mighty Zo. Registered Senior Member

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    Someone stated that the universe was infinite... which seemed to be discounted by this paradox and the big bang.

    >>So eventually while travelling in one direction
    >>you end up at the same place?
    If the universe is finite, then yes you would. This does not create a paradox, since the speed of light is finite and so is the age of the universe.

    My question is, how? If you go in a strait line it seems wrong that you'd end up in the same position. At some point I thought you'd have to hit the end of the universe. Unless the universe is a hypersphere... It seems just as logical that there is an end boundary...
     
  20. Beercules Registered Senior Member

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    342
    The big bang does not require the universe to be finite, as that is just a popular misconception. See http://www.astro.ucla.edu/~wright/infpoint.html

    And under general relatvity, finite universes are hyperspheres, or hyperbolic. But since the light from stars has only been travelling for a finite period of time, you get a dark sky at night.
     
  21. Persol I am the great and mighty Zo. Registered Senior Member

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    Thank you.... a quote from that site:
    Every time I heard the big bang explained, it was the the universe expanded from a point... I guess it is dumbed down for public consumption.
    Does this suggest that the universe was not 'viewable' because atmos had not been formed, or atleast not in substaintial quantities to be seen? Then when they did form... about the same time everywhere... the radiation took time to reach us, so the distance we can see =c*time sine radiation?

    If this is an over simplification and the error is too tedious to explain just state so so I know to read up

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  22. hypewaders Save Changes Moderator

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    you are at the temporal edge of one universe now. And now...
     
  23. chroot Crackpot killer Registered Senior Member

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    By definition we cannot say what is outside our observable universe. It may be either finite or infinite. Either way, the only thing that matters is the observable universe. Any discussion of what's outside it just abject speculation, because it can have no physical consequence.

    - Warren
     

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