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