When choosing the length of time for my scientific equation, it had occurred to me that I could use anything from 1 second up to a century or any other block of years, and would be technically relevant to the discussion. But I chose a day because it is what we are most accustomed to, and our natural rythyms are even in sync with it. You don't get a year to prove your worth in salt, just my opinion. And yes, Americans are f*cking huge, I was shocked when I looked that up....I thought 140 or so, for sure.