Epicycles

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.

If the epicycle on the orbit looked like a wart on an orange, then the refinements looked like a series of ever smaller warts upon warts. Eventually the process of drilling through the math, and keeping track of all of those spinning variables started taking a toll, especially given the lack of raw computational power we enjoy today. What Kepler did was break the cycle of endless cycles upon cycles by pitching circular orbits altogether. He proposed elliptical orbits, and used new calculus tools to keep the equations more elegant.

Now — if you want to know where a planet is going to be at a specific time, there is nothing wrong with epicycles. You certainly can use that system to arrive at the right answer. Kepler’s method, while foreign and new, certainly made things easier in the long run.

Science is about the application of observation to capture truth, through repeatable experiments. If your theory bears out over time and more accurately predicts future events in a closed system — well — it stands until something else overturns the paradigm and starts the cycle of discovery all over again. One of the tools we use to eventually cast away the old, tired system is the use of Occam’s Razor, a philosophical stance that essentially states that given conflicting theories that accurately predict the same phenomenon, the simplest is most likely the best.

And, now having taken this meme for a complete spin cycle, I’ll take a break and come back to this subject, bringing it full circle with regards to communications and “spin.” When I’m not so dizzy… (to be continued.)