Sunday, November 8, 2009

Michelson-Morley, and the death - and birth - of scientific theories

The science is settled. OK, what about Science Magazine?
A new study in the journal Science has just shown that all of the climate modeling results of the past are erroneous. The IPCC's modeling cronies have just been told that the figures used for greenhouse gas forcings are incorrect, meaning none of the model results from prior IPCC reports can be considered valid. What has caused climate scientists' assumptions to go awry? Short lived aerosol particles in the atmosphere changing how greenhouse gases react in previously unsuspected ways.
One of the most annoying arguments presented in the whole Climate Change debate is about "Peer-Reviewed" articles, and how nothing else really counts. This particular article is in Science, which is the Harvard of peer-reviewed scientific journals; mercifully, we won't have to listen to the mouth-breathing "My scientist is red hot; your scientist ain't didly-squat" silliness, as the scientific community gets around to what it does best: testing scientific hypotheses.

Sometimes a hypothesis is confirmed, and leads to a huge advance in our understanding of the universe. Einstein's theory of relativity was confirmed in 1919 when the light from a star was observed to be deflected by the sun's gravity.

Sometimes, an experiment shows that a particular theory is wrong, and this negative result leads to a breakthrough advance in knowledge. The Michelson-Morley experiment in 1887 was one of these.

Their experiment was designed to help understand an anomaly that was pretty vexing to scientists at the time: while light was understood to consists of waves - the radio spectrum is divided into wavelengths - recent advances had shown outer space to be a vacuum. Waves need some sort of material to propagate through - you can't have ocean waves without an ocean, right?

The solution that was proposed was the "Luminiferous Aether", a substance with properties that would allow the propagation of light waves at the very high speed that light was known to travel, while still acting as a vacuum regarding physical matter. Measuring this "rigid vacuum" (as it was described) was - as you can imagine - pretty tricky. Michelson and Morley devised a very clever test that used the motion of the earth through the universe. They reasoned that (a) the earth is moving at around 100,000 km/s in its orbit around the sun, and (b) the sun is moving even faster around the galactic center. This rapid motion across the ether should result in an "Ether Wind" that they could measure. Since the science about ether's properties was well established, the experiment had precise expectations for results.

They used a clever set of mirrors - some of which rotated - and beam splitters to cause a ray of sunlight to be divided into two beams, one continuing straight and the other deflected by 90 degrees. One beam would be following the direction of the Ether Wind; the other would be at right angles to it. After traveling a long enough distance, the beams would be reunited, and the amount by which they interfered with each other (because one had taken longer to travel the same distance, due to the Ether Wind) would be measured. From this, the presence of the Ether and the strength of the Ether Wind could be calculated.

Their results? Nothing. It was "the most famous failed experiment of all time." Of course, it wasn't the experiment that failed - it's been confirmed many times over the years, including by your humble blogger. It was the theory of the luminiferous aether that failed, spectacularly. That failure led to Einstein and Relativity, and Quantum Mechanics, and the Nuclear Age.

So what does this have to do with the current debate about Climate Change? First, it should be a reminder to scientists to keep a sense of humility. Better scientists than you have failed; they weren't the first, and won't be the last. Second, remember that repeating and validating hypotheses is what science does best. There was a quite robust theory of the luminifirous aether, it just couldn't be confirmed.

The scientist proposes, and nature disposes.

There is currently quite a robust theory of how atmospheric Carbon Dioxide "forces" higher temperatures through a rarely-seen-in-nature positive feedback mechanism. OK, nice theory. The problem is that it seems that it doesn't work, at least not the way that was thought. And before you attack the authors as right wing shills of the Oil companies, remember that they work for NASA and this article was published in Science.

Rather than being settled, the scientific debate is robust, and interesting, and changing rapidly. The atmosphere is more fiendishly complicated than we had thought? No big surprise here, except for a politician with an agenda.


Anonymous said...

The experiment didn't so much fail, as point out a way that didn't work.


TOTWTYTR said...

Sometimes proving the null hypothesis is more illuminating than proving the hypothesis. At least if the scientific community isn't dead set on making the results conform to the already decided upon narrative.

Just ask Dr. Robert Stadler of the State Science Institute.

doubletrouble said...


I want by globull warmening; it was 61°(F) here at the ranch, 'n I want more!

You get offen' my lawn...

And TOT? See you at the Gulch...