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I think this assumes the order of magnitude of the size of the observable universe. Clearly if the diameter of the universe is smaller than a proton then you d

by diskcat 11y ago

I think this assumes the order of magnitude of the size of the observable universe. Clearly if the diameter of the universe is smaller than a proton then you don't need 43 digits of pi to calculate its circumference to smaller than the diameter of a proton. So if the diameter of the universe is 10^1000000^100000000 proton wide the precision you need for pi would be way higher than 43?

hanniabu 11y ago
It does depend on the size of the observable universe, which we do know because, well, it's observable.
- diskcat 11y ago
  The post i replied to started off with "If you know the diameter of the observable Universe" but if the result it depends on the size of the observable universe then you ought to say "given the size of the observable universe". Starting with 'if' would imply that the result only requires you 'knowing' the size of the obsv. unv. but does not depend on its actual size.
  - singlow 11y ago
    I think the meaning of "If you know," in this case was more like, "If you take as an input."
    - coldtea 11y ago
      Yep. "If you know X" is commonly used as "given X".
GFK_of_xmaspast 11y ago
There's a difference between "the size of the universe" and "the size of the observable universe", see also "cosmic microwave background", "dark energy", and "inflation."