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We might have a problem

  1. Yes

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  2. No

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  3. Not sure

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  1. Apr 11, 2005 #1
    nother star in the same galaxy, and as long as line AB does not go through the origin(where the big bang occured/center of univesrse), then the stars are also moving apart. Lets do the same with a sun and a planet. Same result (not counting the orbits are elipitical, but circle(ar??)). Lets use two building on earth, same results (not counting plate movement).

    Now, let us use to atoms. Are the results the same. Yes bond forces might hold them together, yet is not there being more strain the farther we move from the origin. When this strain on the atoms become to strong, will not they break. Even if we use quarks, which have no true distance inbetween (i think) yet still occupy to seperate points in 'space'. Will not end the end those bonds break.
  2. jcsd
  3. Apr 11, 2005 #2
    Do not worry, I think you simply misunderstand a lot of basic stuff :smile:
    Matter will not tear apart due to the expansion of the Universe, that is for sure. :rolleyes:
  4. Apr 11, 2005 #3


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    There was some speak years ago about "varying coupling constants", which could be a more precise question.
  5. Apr 11, 2005 #4


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    Just read about this in Greene's 'Fabric of the Cosmos'.

    Expansion of the universe is easily overcome by gravity and by atomic forces. That's why it only has an effect in the gaps between galaxies, where there's very little gravitational pull.

    He likened it to pennies glued to a balloon (in the ever popular balloon = cosmos metaphor). When the balloon inflates, the pennies don't tear apart. The cohesion between the atoms of the pennies (and even the gravitational force between the pennies) is stronger than the penny's attachment to balloon.
  6. Apr 11, 2005 #5

    Dave gave the best reason as to why

  7. Apr 12, 2005 #6

    Part one, when the balloon became to big, it still popped and the pinnies were thrown everywhere, right. But I don't think the universe will 'pop'.

    Part two, lets us have a ballon that will not pop, but get bigger forever. Sooner or later will the force applied on the 'skin' of the ballon where the pinnies are glued start to cause the pennies to come apart. This is hard to envision, because the balloon would have to be (this is just a complete guess) :rofl: the size of the sun. In the end, the question is, is there a force strong enough to tear a pennie apart. Yes, there is. The ballon would have to exert that amount of force in the area the pennie is taking up.

    When the pennie broke, the pennie would bread into small pieces, but not its atoms. Just like the galaxies, they might bread up, but the solar systems should stay together for a long while longer.

    In the end, will not the force applied by the balloon that will not pop become so great, it will rip the molecules of the pennie apart, (again complete guess) :rofl: this might take it becoming the size of the known universe, but as long as the ballon will not pop, then will not it happen.
  8. Apr 12, 2005 #7

    Meir Achuz

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    The universe is not a balloon. Discussing the dynamics of a popping balloon will only help understanding of the balloon. The effect of expansion of the universe on atoms is weaker than negligible, it is irrelevant. Just work out the velocity between the electron and the nucleus due to universe expansion, using the Hubble constant.
  9. Apr 12, 2005 #8
    i was saying the universe would not pop

    and what is the Hubble constant, im still in 10th grade

    and what i want to know is will the force increase untill it can matter, even if it does not now.

    thank you
  10. Apr 13, 2005 #9

    Meir Achuz

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    You sounded more advanced. The relative velocity due to expansion of the universe is proportional to the distance between two objects. (The proportionality constant is called the Hubble constant. This makes Hubble pretty famous since he has a constant and a telescope named for him. ) The particles inside an atom are so close together that their relative velocity completely insignificant.
  11. Apr 13, 2005 #10
    yes, i know the distance, but what is the number i will use, or the forumla. and yes the distance between atoms is so small it is insignificent, but will the force of expansion keep on building untill it is signifince?
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