Curious George

A fountain of material and immaterial information - Things that I spend my days wondering about... and perhaps you have been too? Check out for more curious questions (and answers to them)

Monday, March 24, 2008

All the air and water on earth - Illustrated

Been a long time since I´ve posted anything, so here comes two posts in the same day to compensate
Found a fascinating computer modeling of all the water on our earth and air in our atmosphere illustrated as spheres on top of the earth.

The water on earth is the sphere to the left, and the air is the one to the right. This includes all the water in the oceans, seas, ice caps, lakes and rivers as well as ground water, and that in the atmosphere.
You can either be shocked at how little water and air there is, or just how big the earth is. The air sphere has a diameter of 1 999km, while the water is only 1 390 across
And for those of you who want to see a little bit of rogue theory on how the earth is actually expanding, tune in here:
Very cool graphics on the tactonic plate movements

And finally: The sphere of our human mass (with some assumptions)

6.7 billion humans in the world

Average mass of a human is approx 65kg (Wikipedia says that the mean for the UK and USA is around 75kg; I assume most of the world is lighter than them)

The mean density of a person is 1g/cm3
So humans mass a total of 6.7 billion people x 65kg/person = 4.355x10^11 kg.
At 1g/cm3 this mass takes up 4.355x10^11 litres = 4.355x10^8 cubic meters.
Now we plug this value into the formula linking the volume of a sphere with its radius:
Volume = 4/3 * radius^3
Radius^3 = Volume / ( (4/3) *pi)

Radius^3 = 4.355x10^8 / (1.3333333 x pi)

Radius^3 = 1.0397x10^8

Radius = 470.21 meters
Diameter = 940.43 meters
The sphere of all living human bodies would therefore be a puny 1.8KM across – wouldn’t even be seen on the map I found.



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