The Stonehenge Challenge

Stonehenge was built in three stages from about 3000 to 1800 B.C. The first stage was a circular earth formation; the second consisted of timber being added to the circle; and the third stage was constructed of bluestones. Two hundred to 300 years later, the sarsen stones were added. These are taller than the bluestones and form the upside-down "u" now seen.

Perhaps the most impressive part of Stonehenge is how it was built. The first phase, the ditch around Stonehenge, was dug using antlers, bones and even bare hands. The bluestones, which weighed four tons each, came from over 240 miles away. They had to be floated by boat then carried across land. The heaviest sarsen stone weighed 50 tons and would have had to be dragged along by 500 people. Even if 600 people had been working continuously, it would have taken more than a year to complete.

(This info is from the Teaching Tools site.)

Now, here is your Stonehenge Challenge:

1. Calculate how much effort was required to build the full artifact (man-hours, ergs, horsepower, or whatever method you choose).
2. Determine what fraction of all available effort (in that early society) was used to build this structure.
3. Apply that fraction to the total of all available effort in our modern society to arrive at a Comparable Project Potential.
4. Conceive a new project that would use approximately the same amount of available effort. Then tell us about your project: How would it be accomplished and what would it achieve?

Have fun!

Mike Treder

Tags: nanotechnology nanotech nano science technology ethics weblog blog

Comments

[Roland]

Hey, that's a really good idea.

This will be simplistic, but let's assume that the life expectancy at the time was about 30 years (which may be too high, I'm not sure). Now let's get an age distribution graph for the nation of Malawi which, sadly, still has the same life expectancy.

There are about 10 million people in Malawi, and about 1.8 million are men aged 15-30 years, which is 20%. So 20% are performing actual physical labour on the project.

Wikipedia estimates it took 20,000,000 man-hours to build stonehenge, including the working of the stones. If it took 30 years that's 666,666 man-hours a year. In a society of 1,000 people, that means 200 involved in actual manual labour doing 3,333 hours a year, or about 60 hours a week.

So the answer:

20% of society working 60 hours a week for 30 years
20% of society in jobs directly related to the project

People worked a lot harder in those days, so today you'd have to at least halve the work week to 30 hours. That would mean either:

40% of society working for 30 years or,
20% of society working for 60 years

Plus, a roughly equal number of women and older people would be involved with the project making rope, clothes, food or designing/politicizing. So you would have to double the above percentages.

The next question is, what type of society are we talking about? One country, or the whole world? Let's think about it:

AUSTRALIA (where I come from)
* A 30-year project involving 10 million people

or THE WORLD
* A 30-year project involving 3 BILLION PEOPLE! (At least, because the population will grow during that time)

The only project I can think of that big would be an interstellar spaceship. Australia could do a fairly large one and the World could probably do one half the size of the moon! Or else we could build a space elevator.

Time to get to work.

[Tom Mazanec]

A starship? Do we even have the resources (material), much less the technology for that?

[Roland]

Of course we do! We're just wasting them all on wars, car accidents, smoking, obesity and prisons. We've got our priorities wrong.

If you really devoted millions of people and trillions of dollars, we could have a starship within a few decades. Think how much technology will advance in that time.

It sounds like a lot of money, but relatively speaking, it's not much.

[stacie]

how much man power did it take to build stonehendge?