communication. community. cognition.
Posts tagged Johannes Kepler
Elliptical Thinking
Jan 5th
I promised to bring things full circle, and here we go…
The scientific method does us its greatest service when it simplifies the way we think, understand, and apply our collective knowledge to predicting outcomes. The application of Occam’s Razor is meant to be a guide — not an bulletproof truth in and of itself. In the practical world, there are times when we ought to make fewer cuts. The examples I have in mind involve a different kind of epicycle, focused on time instead of space.
Epicycles
Jan 4th
One of the neat conversations with my wife that sparked my re-entry into blogging had to do with how science marches on, in a constant quest for refinement. I tried to think of an example of how these incremental gains on the truth sometimes lead to a blind alley, and require a complete paradigm shift. For some reason, Johannes Kepler and his laws of planetary motion came to mind.
In more than one sense, this is rather circuitous, as I had recently recalled my “Who Wants to be a Millionaire” moment as a phone-a-friend… the question? Kepler. (I would bring everything back full circle about now, but that is precisely the problem Kepler was trying to avoid…)
As our celestial measurements grew more precise, and our nautical navigators needed them to be, our men of science discovered a problem: what they observed never quite matched what they predicted. When your best measurement of your location was down to a degree or so, this wasn’t as critical. But the further you got from the coasts, the more the star positions mattered, and the more you needed to fix your tools and algorithms. The best means for testing the “drift” in your system was by observing the planets.
The word planet comes from the Greek word meaning “wanderer,” describing the night-to-night path these bodies tended to trace out on the sky maps. The motion was not apparent until you started charting over time — and some of that movement made no sense. Early on, civilizations recognized the strange backwards turn Mars made. The same “retrograde” motion also goes for outer planets, but being further from the Sun, not as easy to track. (The planets don’t really alter course — it’s just a slow-motion optical illusion, analogous to passing a car that is on the outer lane while you are on an inner lane.)
The answer was to tweak the calculations of the orbits… done by adding a small circle to the big orbital circle. Not terribly elegant to calculate, but it did allow the early astronomer to make a decent enough prediction about where the stars and the planets would be.
At least, until his tools improved again, renewing the cycle of recalibration and recalculation.
