something which seems to be true

  

Where D is distance between the subscripted cities, indicated by their airport codes, rⴲ is the radius of the earth, and p is population of the subscripted city.

Since I realized this, I've felt much more conflicted about my coming trip. Separated from my wife for what might be 6 months, in what is by the above measures the most distant city on earth from where I am now (of comparable or larger size). On the other hand, maybe it's symbolic of escape from a long feeling of being trapped - not with the wife, but with the job. Kind of proves I am free, and at the same time there's a cost. There's no cost function in these equations...

The first one was my first thought, just looking at distance weighted by whether the city population is at least as big as Boston's. Melbourne is top there, though Sydney is very close - finding different estimates for population makes the difference, but I think I'm using good numbers - Boston's 'metro' population and Melbourne's similar extent both include 4.2 million people.

The second function is more specific obviously, excluding cities that are larger or smaller, and maybe it's a little more comfortable, but I do prefer the first one.