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Universe expansion

  1. Jun 6, 2004 #1
    i know that the universe is expanding...but i dont understand how

    how can space be created.....like...i know the universe is HUGE...but it has to end somewhere it cant just keep going.....like if say hypothetically that we can keep flying thru space and kept going......would in the end hit a wall or something lol......i just cant picture infinite ..., there HAS to be an end somewhere!
  2. jcsd
  3. Jun 6, 2004 #2
    Picture a balloon with little galaxies on it. Than blow it up. Space expands, universes recede. If you fly in one direction you would eventually end up where you started. Its commonly believed that the universe is as such.
  4. Jun 6, 2004 #3
    Because the size of the universe is related to how much time has passed since the Big Bang,just think of time passing - there is no reason why time can't keep passing.What is the wall that time runs into?
  5. Jun 7, 2004 #4


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    I doubt anyone can imagine the totality of Infinity. But a physical wall makes no sense especially since it begs the question as to what would be on the other side. Observational data suggests that the universe is infinite in extent. But, if space is not infinite, then it curves back on itself somewhat like Parth Dave described.
  6. Jun 7, 2004 #5
    At what scale does logic no longer apply? If causality is essential at all scales, then it applies even to the point where spacetime first came into existence, even before there were any particles. If applies to the most fundamental level, then causality would require that the very first point of spacetime should be the cause of another. If this is the definition of spacetime itself, then it is the very nature of spacetime to expand.
  7. Jun 18, 2004 #6


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    [nitpick]the limits of our current, best physics theories - QFT and GR - are ~Planck time and size; only String/M Theory and/or LQG can help us with the universe at earlier times, and we have *no* indication as to whether which, or any, of these matches reality.[/nitpick]
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