Saturday, August 29, 2009

101 Interesting Things, part twenty-two: The Coastline Paradox

So I've been in e-mail contact with island, who commented on my second Abusive Cosmology post. I had previously known that Earth is a rare specimen, but I have since gained a much greater appreciation for just how rare our circumstances are here on this pale blue dot.

Earth occupies what is known as a "Goldilocks Zone," a whimsical yet apt term which amounts to walking a knife-edge between competing runaway forces. Uninhabitable extremes characterize the overwhelming majority of the Universe and prevent life from cropping up almost everywhere. However, these opposed runaway forces of extreme heat and cold, crushing gravity and hungry vacuum, as well as others, occasionally strike a balance between them that makes it possible for life as we know it to arise and thrive.

Now, we can imagine Goldilocks Zones for any phenomenon we'd care to dream up, be it life, molten metal, solar flares, factories, or whatever. The simple fact of the matter is that there are just about always more ways for any given thing to not exist than there are ways for it to exist. What's interesting is that these Goldilocks Zones have relevant features at all levels of reality. In terms of life, there is a Goldilocks Zone between Earth's mantle and its ionosphere into which all life has shoe-horned itself. Locally, every organism has its niche, and there are plenty of places on the planet where any organism you'd care to name simply could not survive: no species can survive absolutely anywhere on Earth.

Earth itself is in a Goldilocks Zone relative to our star, Sol: too close and we burn, too far and we freeze. Our solar system itself is a roll of the die that came up "life-friendly," with gas giants sweeping up the riff-raff of cosmic debris (which would otherwise pelt every small rocky world into oblivion), and without so much eccentricity in their orbits as to screw with the inner rocky planets. And the position we occupy in the galaxy is far enough out from the gene-scrambling radiation of the galactic core, but not so far out as to lack the heavier elements needed for more complex life. With respect to time, life cannot come about during the initial or final phases of a planet, star, galaxy, or Universe (at least, not a Universe that starts with a Big Bang and ends with either a Big Crunch or heat death). And with respect to physical laws, they have to be such a way as to allow life to be possible anywhere at all (though whether they could be otherwise is at present an open question).

This preponderance of interesting features reminds me of the Coastline Paradox, which refers to the difficulty of determining the "exact" perimeter of a coastline. You see, coastlines have relevant features at all levels of detail, and these change on all timescales. From biggest to smallest, coastlines have features observable from space that change in geologic time, and features on the more human-appropriate scale of meters that change daily with the tides, and features on the atomic scale that change rapidly all along the progression and recession of every single wave.

So what's the "true" length of a coastline? Ain't none. We can arbitrarily decide which features are important and which are not (the Wikipedia page mentions the appropriately useful tactic of omitting features significantly less than the unit in which the measurement is being made), but no output from any such method has a privileged status over any other. Trying to find the true or exact length of a coastline, even in a snapshot of time, is like trying to find exactly how many grains of sand constitute "a heap."

3 comments:

Zach L said...

The very first thing I thought of when reading this was the most recent Dinosaur Comics, which you must have been thinking of too, since you mentioned the same thing!

Good times. Although I don't think they're QUITE the same, since one of the problems can be solved with semantics and the other isn't really a linguistic problem so much as a measuring one.

Mr G Montag said...

Me, I think more about language, concepts and incompleteness. Meaning is including just enough to get the idea across which lets go of quite a lot of useless stuff.

It also reminds me of all those claims that science doesn't address "ultimate meaning" or ethics and I'm always left thinking well, there's all this stuff here and you haven't told me what I'm supposed to be measuring.

I end with wisdom from Massimo Pigliucci and Stephen Novella.

D said...

Wow, Z, I actually hadn't read that Dino Comics yet! But it sure is awesome! I am so excited about this that I cannot stop using exclamation points! Hurrah!

What I was going for was more the idea that both of these things have interesting features at multiple levels which make them difficult to define precisely. But that's really just a quirk of language, since we don't need to compile our concepts with the rest of our conceptual hierarchy before using them.

Mr. G, this is a convenient point to segue to your comment. That's actually a pretty good account of how language works, and I share your frustrations with respect to the disconnect between technical science and everyday language. Defining our terms precisely is tough stuff, and expecting science to make itself compatible with fuzzy/mushy terms like "ultimate meaning" just strikes me as silly.

Thanks for the comments, both of you!