
What's the smallest country that can fit everyone standing six feet apart? - milkbikis
https://banga.github.io/blog/2020/03/28/smallest-country-that-can-fit-everyone-six-feet-apart.html
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meigwilym
I may have missed something but shouldn't the radius be 3 feet? With a 6 foot
radius, wouldn't everyone be 12 feet apart? The maths is new to me (I was OK
up to πr2!) so this might be my mistake.

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kjaftaedi
The subject would be in the center of the circle.

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meigwilym
Indeed, they would, with 6 feet to the edge of their circle, and another 6
feet from that edge to the next person.

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radmarshallb
You are correct. The diameter should be 6 feet and the radius 3 feet.

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marzell
That means people would only be at least 3 feet away, not 6 feet. The original
assumption was right.. need a 6 foot radius, 12 foot diameter to meet social
distancing guidelines

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kd5bjo
It’s a circle-packing model, which means there’s no overlap between the
exclusion zones. A radius of 3 feet means you’re at least 3 feet away from the
edge of anyone else’s circle. They are at the center of their circle, which is
an additional 3 feet away, for a total of 6 feet.

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andrewaylett
If we're packing circles, don't we need to take into account that the 6ft
distance is to the next person -- that is the centre of the next circle,
rather than the boundary of it?

That means circles of radius 3ft, for a total of 8,693 square miles.

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iamthepieman
This only works if the target country is a circle itself. The packing method
becomes much more difficult when you have to deal with arbitrarily complex
shapes. We run into this type of problem in windfarm planning.

You have a ridge with discontinuous bands of acceptably sloped terrain,
usually highly irregular shapes and you have to fit wind turbines along it,
taking into account the minimum clearance between turbines and pack as many as
possible within. This type of problem is NP-Hard and almost always ends up
being done manually due to additional constraints. These include, access road
placement, viewsheds, and turbulence modelling.

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cromulent
You can fit all the humans on earth into a 1km cube.

Average volume of a human is 66l [1]. Make it 130l to allow some unused space
due to imperfect packing.

7.6 billion * 130l = 988 000 000 000 liters.

1 cubic kilometer = 1 000 000 000 000 liters.

[1]
[https://www.wolframalpha.com/input/?i=average%20volume%20of%...](https://www.wolframalpha.com/input/?i=average%20volume%20of%20human%20body)

~~~
Simon_says
You wouldn't enjoy it.

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metaphor
As a more practical usecase, how many other EEs have leveraged circles-in-a-
circle packing tables such as [1] to approximate cable diameter and/or size
conduit?

Would be interesting to learn how other disciplines have applied such a tool
to solve real-world problems.

[1] [http://hydra.nat.uni-
magdeburg.de/packing/cci/cci.html](http://hydra.nat.uni-
magdeburg.de/packing/cci/cci.html)

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m11a
This seems to be a dramatic simplification, to the point where the results
aren't helpful at all, unless I'm missing something.

A lot of this is private property. Offices, people's houses, a farmer's
farmland. We can't go inside, or trample on the crops of farmers. Then you
need to subtract roads - because you can't walk on a road and definitely not a
motorway.

So really, shouldn't the land area used be the _publicly accessible pedestrian
area_?

And I dunno about others, but my footpaths are less than a metre long in width
in my residential area. In the commercial areas, they tend to be less than 6
metres.

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harry8
"Stand on Zanzibar"

Memories of enjoying it with that one.

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sigmaprimus
Things are pretty tight in Singapore, I wonder if you take into account places
not safe to stand like roads and places occupied by walls, trees, bank vaults
etc., if it would be impossible. Almost 6 million people in 7.8 billion square
feet if it was just flat land = approx 1300 square feet per person if my math
is right.

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eesmith
The density needs to exceed 223,563/sq. mile (says the essay).

Singapore's density at 20,445/sq. mile is less than 1/2 that of Monaco, says
its reference 5, which is
[https://en.wikipedia.org/wiki/List_of_countries_and_dependen...](https://en.wikipedia.org/wiki/List_of_countries_and_dependencies_by_population_density)
.

Thus, only 10% of the land is needed, giving plenty of space for roads, etc.

Of course, if you include walls then you can place people on either side of
the wall without an infection problem, so that changes the calculation
considerably.

FWIW, I wondered if Vatican City could reach the limit during a papal
audience. It looks like perhaps 15,000 people could be there for one? That
alone gives a density of 88K/sq. mile (bearing in mind that Vatican City has
nearly 6 popes per square mile - or nearly 12 if we include Popes Emeritus.)

Then there's the staff, and the people visiting the museum, and others beyond
the estimated population of 1,000.

Even with those, it doesn't seem like it comes close to 223,563/sq. mile.

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sigmaprimus
I stand corrected, also the model does not take into account the Z axis,
magnitudes of area added by highrises.

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robertlagrant
Yes - it really should be spheres, but ones that cannot use other spheres for
support :-)

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eesmith
I think "should be" pushes things beyond the limited humor there was.

The 6 feet suggestion is based on the travel distance of possible virus-
carrying particles, given people on a flat surface.

Since gravity pulls particles downward, I suspect that being 5 feet above
someone sick is better than being 6 feet below. Possibly even better than
being 6 feet to the side.

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grabball
I find impossible to read those kind of things when you use the United States
customary units

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choeger
I don't know it is easy to translate feet from US to German. I just need to
know which city the unit refers to:

[https://en.m.wikipedia.org/wiki/Obsolete_German_units_of_mea...](https://en.m.wikipedia.org/wiki/Obsolete_German_units_of_measurement)

/S

(honestly, once the US empire is gone for good, historians will have a good
laugh about their stubborn refusal to adopt the metric system. Must be the
worst case of NIH in history)

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scraft
To be fair, over here in the UK, we have MPH for roads, stones and pounds for
peoples weight (kilograms are becoming more popular, in particular for the
under 25s), feet and inches for peoples height (meters becoming more popular
for under 25s). So we have a bit of a hybrid really, I am 36 so get a bit of
both, but my parents need everything converted to "old money" as they call it,
they can't imagine what 25cm length is, they would need it in feet and inches.
It is less stubborn for them, more, "why bother"? They can get by as is and
have other things to occupy their time than trying to work out what familiar
distances and weights are using a different scaler. Given that roads are still
imperial as are lots of other things (mattress sizes, timber sizes, etc) it
isn't like if they switched to metric it would even fix anything useful.

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RugnirViking
I think the important distinction here is that the UK is definately on the
path to transitioning away sensibly in that imperial units haven't been taught
at any school at any level for many years. All product units (litres, kgs etc)
in shops are given in both metric and imperial, with the metric part required
by law and the imperial part there for old people's convenience.

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kd5bjo
In an odd way, the US is fully metricized: they’re one of the original
signatories of the Treaty of the Metre, and redefined all of their legacy
units in terms of SI ones [1]. SI units are used directly in the sciences and
most products have the SI equivalent listed alongside the traditional measure.
I understand that industries with international supply chains, like the auto
industry, are also mostly metric these days.

There just hasn’t been much of a reason for the purely-domestic parts of the
market to switch: house builders are looking for 2x4 lumber, and won’t buy
from a lumberyard that calls it 50x100mm. Knowing that, the sawmills continue
producing the 1.5x3.5 inch profile that’s called “2x4” and anything else is a
specialty item. Who has an incentive to push through the change?

[1]
[https://en.m.wikipedia.org/wiki/Mendenhall_Order](https://en.m.wikipedia.org/wiki/Mendenhall_Order)

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tenant
So, my country which feels big to me couldn't do it. This reinforces my belief
that there are way too many of our species on this planet. Given that 2.1 or
so is the replacement rate, a "hard" limit of two child per woman would be
decent compromise as this would equate to somewhere around 1.7 taking into
account women who don't want to /can't have children. In one generation, if
there were no unintended consequences this would drop the population by 15%.

Sometime in the 2100s it would be half what it is today and my country could
easily fit everyone!

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colechristensen
Most of the most-developed countries in the world are reproducing below the
replacement rate already, populations only growing because of immigration.

[https://en.wikipedia.org/wiki/List_of_sovereign_states_and_d...](https://en.wikipedia.org/wiki/List_of_sovereign_states_and_dependencies_by_total_fertility_rate)

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tenant
I was thinking globally since the discussion was about the global population.

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colechristensen
There seems to be a generational lag between infant mortality (or mortality
before reproduction) and fertility rate.

Many places still have very high mortality-before-reproduction rates and
correspondingly high birthrates, or at least generational recent ones.

It seems, simply, that overpopulation is a problem which solves itself. High
standard of living seems to come with high costs and emphasis on investing in
children far more combined with delaying children until proper resources can
be had. The result? Fewer children.

The doom and gloom about overpopulation was overblown and doesn't look to be a
problem. We have enough food production capability (especially with new lands
to open up with global warming), hunger comes from dysfunctional economies,
not lack of food.

It doesn't make much sense to think about global population as a whole when
there is such variability. You can't compare Manhattan to sub-Saharan Africa
at all, they are totally different worlds (or perhaps a hundred or two years
apart developmentally).

