### Mathematically, you are my 23-rd cousin!

I made a complain on my Facebook and Google+ status today. I arbitrarily assumed that any Asian is at least my 100-th cousin. Then I realized I made a big mistake - there aren't $2^{100}$ people in Asia + Asian population in the US and Canada!

So, what degree'' of cousin are you to me?

Let's assume all humans on planet Earth at this moment has a pair of common ancestors, according to either some religious documents (e.g., Biblical Adam and Eve) or some molecular biology hypotheses (e.g., Y-chromosomal Adam and Mitochondrial Eve).

And, there are 6.5 billion people on planet Earth now.

Let's assume every couple in the history of mankind has $e= \lim_{n \rightarrow \infty}{\left (1 + \frac{1}{n}\right)^n} \approx 2.718$ children that can reproduce grandchildren on average. (e is the mathematical constant a.k.a. Euler's number that can magically describe many phenomena in our universe.)

Because the natural logarithm of 6.5 billion is around 23 ($\ln(6.5\times 10^9) \approx 22.595$ ), everyone on planet Earth now is at least my 23-rd cousin.