Comments on: What's Your Cosmology

Question: What's Your Cosmology

goalyeehah — Mon, 21 Aug 2006 17:43:24 -0800

I am looking for sources that give the weight of the earth, volume of all the oceans, total acreage on the planet, total current population and guestimated total weight of said population.

I am doing personal research for a question that came to me last week. I would like to find how much space does the current population of the planet occupy?

By: cillit bang

cillit bang — Mon, 21 Aug 2006 17:53:14 -0800

Wikpedia: Earth
- Weight of the earth: 5.9742×10^24 kg
- Acreage of the planet: 148,939,100 km²

Wikpedia: World population
- Total current population: A little over 6.5 million

Wikpedia: Ocean
- Volume of the oceans: 1,340 million cubic kilometers

Wikpedia: Human
- Average weight: 62 kilograms
= 403,000,000,000 kilograms total

By: twiggy

twiggy — Mon, 21 Aug 2006 17:53:29 -0800

This falls under the google is your friend category...

By: Galvatron

Galvatron — Mon, 21 Aug 2006 18:07:05 -0800

Population of humans only?

"How much space" is not well-defined. Are you looking for the physical volume of all humans, the surface area covered if all humans were to simultaneously lay down, or perhaps the number of 1 km² segments with at least one human occupant?

By: purephase

purephase — Mon, 21 Aug 2006 18:12:17 -0800

So, you're asking for the world? I'm here all week.

By: goalyeehah

goalyeehah — Mon, 21 Aug 2006 18:12:43 -0800

When I posted, I was think surface area covered by someone standing.

On re-read, I would also want surface area covered if all humans were to lie down.

And while I am at it.........the volume of the livable atmosphere.

By: Neiltupper

Neiltupper — Mon, 21 Aug 2006 18:14:11 -0800

Weight of the earth: 5.9742×10^24 kg

Not to be pedantic, but the correct term is mass, not weight.
"weight of the Earth" is essentially a meaningless phrase.

By: smackfu

smackfu — Mon, 21 Aug 2006 18:36:50 -0800

To be pedantic, would the weight of the Earth be zero, give or take a bit?

By: cillit bang

cillit bang — Mon, 21 Aug 2006 19:14:44 -0800

Not to be pedantic, but the correct term is mass, not weight.

Yeah, I know that. I was reusing the poster's headings.

On re-read, I would also want surface area covered if all humans were to lie down.

Ask Metafilter isn't a place where you "want" things. It's a place where you politely ask the community to help you with a problem. I'm shown you how to find the information you want, so your problem should now be solved.

By: Galvatron

Galvatron — Mon, 21 Aug 2006 19:46:35 -0800

The poster's most basic questions are easily searched, but the question of surface area covered is actually kind of non-trivial because the world population is not composed of 6.5 billion average humans.

I would start by using 2002 global census data to get a histogram of age distribution. I would then convert this histogram into an approximate weight distribution using a 2002 table of mean weight by age (US data was the best I could find). This diagram suggests that an average adult male has a maximum horizontal cross sectional area of about 170 in², and according to Wikipedia that average person has a weight of 78kg.

Now, assuming humans are geometrically similar (yeah, right...): C = k * W^2/3 where C = cross sectional area and W = weight. You can solve for the constant of proportionality k using the average adult male cross section and weight given above (feel free to use a vertical cross section if you really want the data for humans lying down).

Now apply this formula for every column of the weight histogram to get a distribution of human cross-sectional areas. Sum over 6.5 billion people, and you've got a reasonable estimate. I look forward to reading your results.

By: notswedish

notswedish — Tue, 22 Aug 2006 08:49:24 -0800

I'm pretty sure that 62 kg the average weight for an adult human. I'm also pretty sure that children make up a considerable portion of the 6.5 billion humans. So the total mass of humanity probably a bit less than 403 billion kilos.

By: notswedish

notswedish — Tue, 22 Aug 2006 08:50:29 -0800

Umm, please insert the word 'is' in its correct places in my preceding comment. Thanks.