[ExI] Are Cities Dead? (was Re: moving bits, not butts)

Samantha Atkins sjatkins at mac.com
Wed Mar 2 04:51:40 UTC 2011

On Mar 1, 2011, at 8:22 PM, spike wrote:

> ... On Behalf Of Samantha Atkins
> ...
>> Cities are also good for enabling you to live a mile away from your 
>> neighbor.  If the population was evenly spread over the Earth's land 
>> surface in a square grid, there'd be a person every 140 meters.
> Using the entire surface area to get spherical surface area, dividing by
> 6 billion and multiplying by 0.30 which is the percentage of land I get over
> 25 km between people.  This is a lot more believable than a person every 140
> meters.
> - samantha
> Using the .3 factor I am getting 140 meters between each person.  
> Earth radius about 6370 km, so surface area , 4 pi R^2 = 5E14 m^2, 
> 0.3 of that is dry land, so 1.5E14 m^2 divided by 7E9 is about 2E4 m^2 per
> person or about 140 meters between each person.

Ah, I see my mistake.  2E4 m^2 is roughly the same as my 2.5E4 which I forgot to divide by pi and take the square root of which gives 158 meters radius of circle/per person so twice that between people or 316 meters.   That is an impressive number.

- s

More information about the extropy-chat mailing list