December 29 – Method To The Madness

Today’s factismal: Most scientific papers either refute or clarify earlier papers.

If you ever want to see raw, vicious criticism, head for a science conference. You’ll see posters and presentations of the latest ideas and data – and you’ll see hordes of people with contradictory opinions doing their best to tear the presentations to pieces. They’ll decry the lack of predictive or explanatory power (a good hypothesis both explains and predicts; sadly, most hypotheses only do one or the other). They’ll they’ll argue over whether or not the poster has enough data to back it up (data is the lifeblood of science). And they’ll try to come up with alternative explanations for the data that they do have.

For an example of that, consider the story of the four billion year old diamonds. Back in 2007, Martina Menneken, Thorsten Geisler and Alexander Nemchin took a look at some zircons that had been found in the world’s oldest rocks. Known as the Jack Hills craton (craton is geology speak for “really old rocks”), the zircons in those rocks had been dated to 3.8 billion years old. But the zircons are actually older than the rocks; they appear to be about 4.3 billion years old. That would mean that the Earth had solid rocks on the surface just 200 million years after it formed which is surprisingly fast, considering that it was covered by an ocean of molten rock at the very start.

So far, there isn’t any controversy; everyone is fairly confident in the ages of the rocks and the zircons that they hold. Where the arguments begin is with some diamonds that seemed to be trapped within the zircons. Those diamonds were dated to be 4.4 billion years old, making them the oldest known material on Earth and indicating that the magma ocean cooled rapidly. And that idea caused a lot of arguments. How could so much rock cool so quickly? Where did the heat go to? Where did the diamonds come from? And why were the diamonds so sharp?

The diamonds in the zircon are too sharp to be original material; they must be from teh polishing compound (Image courtesy ;laskdhf;skdj; et al)

The diamonds in the zircon are too sharp to be original material; they must be from the polishing compound
(Image courtesy Dobrzhinestskaya et al)

That last point was telling. Even a diamond will erode in 100 million years, so the diamonds found in the zircons should have been smooth. Instead, they were sharp. And so Larissa Dobrzhinetskaya, Richard Wirth, and Harry Green decided to take another look at the zircons. When they did, they discovered that the diamonds weren’t actually inside the original zircon; instead, they were grit left behind by the polishing that was used to prepare the zircons for a trip through the electron microscope. Their results were so clear that even the authors of the original study admit that they made a mistake.

And that’s how science actually works. We argue. We check each other’s work. And we always look for more data to help us decide which ideas are right. If you’d like to stoke the controversies by adding more data, then why not head over to WildObs? They are looking for “field photos” of animals so that they can track changes in the environment; they’ll even help you identify that unknown critter in your picture! To participate, click on over to:
http://wildobs.com/

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