Wednesday, January 18, 2006

No Second Chances

The universe appears to be a hostile place. There are a number of relatively frequent galactic scale events that, should they occur within hundreds or even thousands of light years away from earth, would likely cause a mass extinction event that would wipe humans from the earth. (Or, at a minimum, cause a regression in the state of our civilization back to that of early hunter-gatherer societies, since our domesticated food sources would also be devastated).

Even in our own solar system, there is some evidence for fairly recent catastrophic events that might have the same impact on our technology and agricultural levels.

And of course, there are also the local events on our little ol' earth. Most of these classic scenarios you've probably heard about - nuclear winter, biological pandemics, and other man-made disasters.

Now, some of you may take the long view, and say so what - if there are a few thousand humans left, then they will quickly (a few thousand years?) rise again.

But it doesn't appear that would be possible. Let's go ahead and say that one of these many events occurs and leaves behind a few hundred thousand humans. Let's say that they're not so widely scattered that some thousands of them couldn't get together to form a community. Let's also say that the knowledge of our current technologies survives, and is available to these folks.

The trouble is, there just won't be any natural resources left to actual construct a technological civilization again.

For a civilization which doesn't have much in the way of technology to access natural resources, those resources must be easily available using the tools at hand. This means that ores, chemicals, petroleum, and other resources must be essentially at the earth's surface. (Deep drilling, mining, and ocean based resources are all out of reach).

Let's look at this post-apocalyptic world, and see what we can find. Oil? Nope. While estimates of the world's oil reserves vary, the easy patches (like where Jed Clampett only needed to miss his shot at the possum to bring up black gold) are gone. Which not only means no easy, portable energy resource - it also means no plastics, polymers, and other materials out of which just about everything today is built.

How about other energy sources, like alcohol or steam? Well, to harness these, you need the products of an Iron Age. Uh oh. Most ready surface sources of iron ore were depleted long ago. But hey! We'll have all those old cars and building beams that we can melt and use, right?

Wrong. Iron (and steel, which is just iron combined with carbon) love oxygen - love it so much that it will combine at every opportunity, forming rust (iron oxide). The resulting rusty sludge that will seep back into the groundwater is iron oxide. It's possible to extract iron from iron oxide, but it's hard without electricity and other metals like aluminum or magnesium - and modern technologies.

Ok, then what about at least the Copper Age? Darn it - I just finished reading an article that we're already running out of copper too.

Aluminum, like iron, is fairly abundant. But to work it really requires a lot more energy than iron, usually only provided using lots of electricity. Which we don't have. Because of the lack of copper and iron to build wires and engines.

Anyway, you get the drift. We really have one chance to advance far enough technologically to get off this planet and spread our eggs out over more than one basket.

If we blow it, we won't get a second chance.

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