poly: How many people?

I'm proposing a "limiting nutrient" puzzle. It's only a little
bit scientific, but I think it will be amusing.

Suppose that we push John McCarthy's debunking of the Population
Explosion to the limit, and ask "How many people can we make out
of the elements in the Earth's crust?"

We consult one of those tables that sez people contain X% Carbon,
Y% Oxygen, and three atoms of administratum. Then we find out
how much of each is in the Earth's crust, do the divisions, and
conclude that at most 2.3 quintillion people of mass 70 kg can
occupy the surface.

I think the same question is also interesting for the solar system,
and not for the galaxy or universe. This is based on the assumption
that redesign won't have eliminated the dietary requirement for
attograms/day of administratum, but that fusion will be used to
convert most of the galaxy's H to C++. (This raises some interesting
environmental concerns -- what do we do with all those gamma rays,
and how do we save the energy till we need it -- but I'll punt.)

My initial guess is that P will turn out to be the limiting crustal
ingredient, but that I (Iodine) will be the solar-system limit.

Rich Schroeppel rcs@cs.arizona.edu
Received on Mon Jun 29 19:48:27 1998