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> The problem in an infinite universe is every possible location in the sky eventually terminates on a stellar surface - a star. Isn't that only true if the un

by Gupie 5y ago

> The problem in an infinite universe is every possible location in the sky eventually terminates on a stellar surface - a star. Isn't that only true if the universe is infinitely old as well as infinitely large?

XorNot 5y ago
Sure, but postulating an infinitely sized universe (full of an infinite amount of mass) does ask the question as to why the universe would not be infinitely old? Particularly when you get into issues like entropy, which is the only real determinant of time even existing. A finite universe has a natural direction of entropy - whereas an infinite one does not, since there's an infinite amount of mass and energy and as such no possible lowest possible entropy state. It's actually worse then that though: an infinite massed universe by definition would contain every possible configuration of that mass somewhere within it. So you and I talking right now like this, our past and future conversations would also all be somewhere else in the infinite universe happening simultaneously. A universe with an infinite amount of mass and energy in infinite space doesn't really have any sensible notion of past, present or future - because all possible pasts, presents and future, exist at all times somewhere within it.
- gilbetron 5y ago
  > A universe with an infinite amount of mass and energy in infinite space doesn't really have any sensible notion of past, present or future - because all possible pasts, presents and future, exist at all times somewhere within it. This is actually untrue for many reasons, but one is that there are different kinds of infinities. For instance, there are an infinite amount of real numbers between 0.0 and 1.0, and none of them are pi. Just because something is infinite, doesn't mean everything is possible within that infinity. Again, there are an infinite number of integers, but none of the are pi or 0.1 or 37.5
  - XorNot 5y ago
    All possible configurations was the term used. We aren't living impossible configurations of matter in our day to day reality.
    - gilbetron 5y ago
      > an infinite massed universe by definition would contain every possible configuration of that mass somewhere within it. That was the statement, a universe with a 1kg blob of matter every billion light years would be infinite massed, but would not have all possible configurations.

by Gupie 5y ago

XorNot 5y ago

Sure, but postulating an infinitely sized universe (full of an infinite amount of mass) does ask the question as to why the universe would not be infinitely old? Particularly when you get into issues like entropy, which is the only real determinant of time even existing. A finite universe has a natural direction of entropy - whereas an infinite one does not, since there's an infinite amount of mass and energy and as such no possible lowest possible entropy state. It's actually worse then that though: an infinite massed universe by definition would contain every possible configuration of that mass somewhere within it. So you and I talking right now like this, our past and future conversations would also all be somewhere else in the infinite universe happening simultaneously. A universe with an infinite amount of mass and energy in infinite space doesn't really have any sensible notion of past, present or future - because all possible pasts, presents and future, exist at all times somewhere within it.

gilbetron 5y ago
> A universe with an infinite amount of mass and energy in infinite space doesn't really have any sensible notion of past, present or future - because all possible pasts, presents and future, exist at all times somewhere within it. This is actually untrue for many reasons, but one is that there are different kinds of infinities. For instance, there are an infinite amount of real numbers between 0.0 and 1.0, and none of them are pi. Just because something is infinite, doesn't mean everything is possible within that infinity. Again, there are an infinite number of integers, but none of the are pi or 0.1 or 37.5
- XorNot 5y ago
  All possible configurations was the term used. We aren't living impossible configurations of matter in our day to day reality.
  - gilbetron 5y ago
    > an infinite massed universe by definition would contain every possible configuration of that mass somewhere within it. That was the statement, a universe with a 1kg blob of matter every billion light years would be infinite massed, but would not have all possible configurations.