Friday, April 06, 2007

A Change of Tune

The improver of natural science absolutely refuses to acknowledge authority, as such. For him, scepticism is the highest of duties: blind faith the one unpardonable sin. ~T. H. Huxley

I've gone on at length about theories that seem to be published just to be publishing something and theories that seem to depend on overly complicated methods to explain something already suitably explained. It seems that some other people are beginning to feel that way, too.

For example, take "snowball earth." It's been theorized that, around 600 million years ago, we had the ice age to end all ice ages. The entire planet was encased in ice and might have remained so had not volcanism pumped enough greenhouse gasses into the atmosphere to start warming things up again. A lot of the evidence for this depends on the existence of "drop stones" at equatorial latitudes where glaciers shouldn't happen.

Now, a UK-Swiss team has found that, within that time frame, there were hot and cold variations in the climate, based on weathering of sediments. The data doesn't eliminate the possibility of a complete global freeze, but it certainly puts limits on it. It will probably force a review of the snowball scenario to see how the weathering data can be fit into the theory.

Meanwhile, not to long ago, the Science Channel had a nice pair of programs discussing how the demise of the dinosaurs resulted in the rise of the mammals, which has been the established view for some time now. But an international team has completed the most comprehensive "family tree" ever done for mammals. Their conclusion is that mammals were doing some serious diversifying prior to the extinction event that occurred 65 million years ago. More importantly, some of these mammals from the Cretaceous are ancestral to today's mammals.

Note that the team is not saying that really big mammals were running around biting T-Rex on the toes. But, they are saying that the roots to us were already forming while the dinosaurs were roaming the earth.

But the most interesting potential shocker involves dark energy. When it was discovered some years ago that the expansion of the universe, contrary to intuition, was increasing, not slowing down, the mechanism invoked to explain the effect was dark energy. In fact, pretty soon, cosmologists were saying the 75% of the universe was made up of something we can't see, can't detect, and can't define properly.

Evidently, that began to bother some people, in particular a physicist at CERN who holds that dark energy may not be needed to explain the expansion speed-up. Syksy Rasanen's theory smacks of the old "great attractor" except on a local level. Basically, his theory says that local mass concentrations (like bunches of galaxies) actually experience a slowing of expansion, but, in the huge voids that exist between such concentrations, the expansion is unchecked. As the dense regions become more compact, the expansion factor for the voids becomes a higher component of the overall average expansion rate. So, as the dense areas become more compact, their influence on the void areas declines, and the expansion factor appears to increase.

So, you don't need a repulsive force provided by dark energy to account for the apparent increase in the expansion rate, because that's all it is: An apparent increase.

Not surprisingly, this theory isn't sitting well with the dark energy crowd. But, on the other hand, Rasanen doesn't need to invoke any sort of exotic forces to get the same result. Occam's Razor would seem to favor him.

It's intriguing that we suddenly have a spate of, what might be called, "debunking" theories in contrast to the trend of exotic and sometimes downright strange theories that need cosmic rays, strange forces, and torturous mathematics to work. That doesn't mean that the simpler theories are right; sometimes life, the universe, and everything does turn out to be complex. But it is interesting to see a slightly different approach based on actual evidence. rather than saying, "As soon as we get some new information, we'll be shown to be right."

Sometimes you have to go where the data leads you until some new data leads you somewhere else.

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