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E-folding explaination needed

  1. Feb 27, 2013 #1
    I've tried several searches on the term e-foldings, However I've been unable to find any decent write ups on the terminology or calculations. Surprisingly even Wiki doesn't have much on the subject.
  2. jcsd
  3. Feb 27, 2013 #2


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    Staff: Mentor

    Well, let's look at two articles from wiki.

    First: http://en.wikipedia.org/wiki/E_folding
    Second: http://en.wikipedia.org/wiki/E_(mathematical_constant)
    If I'm reading this correctly, it appears that e-folding is simply the amount of time it takes for space to expand by approximately 2.71828 times its original size. Does that help at all?
  4. Feb 27, 2013 #3
    Ah yeah it does the second link provided the details I needed. I couldn't figure out how they derived the 2.71828 value thanks so much
  5. Feb 27, 2013 #4


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    Science Advisor
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    Dearly Missed

    Quite right! And loge 10 = 2.3
    So 60 e-folds is the same as 26 "ten-folds"

    Distances increasing by a factor of e60 is the same as their increasing
    by a factor of 1026
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