Tuesday, August 23, 2005

Paleo Sensationalism

I suppose it has to do with the way things are presented these days: Big headlines for minor stories, overblown news items, overhyped TV programs and products. When it extends to science, though, it’s time to stop.

I watch the Science Channel a lot. In fact, my TV viewing is pretty much down to History International, Science Channel, Discovery Times (when they show history or science), and a little National Geographic channel. Turner Classic Movies gets some attention, and, of course, I must not omit Boomerang (Looney Toons, forever!). With that limited repertoire, I take their content seriously; when there are errors or distortions, I get upset.

So last night, I tuned in with interest to see “what really killed the dinosaurs.” For some years know, there has a developed a consensus that the dinosaurs, who lasted for 165 million years, thank you, got finished off by a huge meteor impact. A mathematician named Alvarez and his son put this theory together, which got a huge sneer for years from paleontologists until the Iridium deposit was found worldwide which neatly divided the strata where there were dinosaurs from the strata where there weren’t any. A crater was found off the Yucatan which seemed to fit the size and timing to meet the requirements of the theory.

Now not everyone is on the bandwagon with the meteor folks. It has been argued for years that huge lava outflows (notably the Deccan Flats in India) could have contributed to a long-term decline of the dinosaurs. Others have pointed out that there was already a significant climate shift going on, which the volcanism only would have exacerbated. Finally, a few feel that due to a land bridge forming with areas that had been cut off for a long period of time, disparate dino populations came together and exchanged diseases. So I was intrigued to see what this “shocking new evidence was”.

It was codswallop, that’s what it was.

Basically, it was a couple of paleontologists who argued it wasn’t the Yucatan meteor that did it, it was another one that came 300,000 years later. That’s it? It wasn’t one meteor, it was another one? The only thing that was shocking about that is that anyone chose to argue the point.

Their evidence wasn’t very good, to boot. They based their conclusion on a sandstone layer in the Yucatan that most scientists feel came from the tsunami caused by the meteor impact. At the bottom of the layer, there are little molten globules, dirt made molten by the meteor. Then there’s a big layer of sandstone, which is followed by the iridium layer. They said the time to deposit that sandstone was very long (300,000 years) so the iridium and the globules couldn’t be related.

Although this explanation of how the sandstone meant such a long period of time had passed, it appeared that they were debunking the meteor extinction theory. So I waited with interest to see how they would explain the iridium, which is rare on Earth, but common in meteors. Then they hit me with the second meteor.

Now a proponent of the Yucatan meteor did a pretty good job of showing that the other guys were pretty sloppy in their interpretations of the sandstone. I guess they figured they didn't have to ask this, but I though there was one very pertinent question:

If there were two meteors, where's the iridium layer from the other one?

Perhaps realizing that the "shocking new evidence" was, in fact, pretty lame, the program took a sharp shift and started knocking other aspects of impact extinction theory. For example, if you have a monstrous impact (or massive volcanism for that matter) you get acid rain. For some reason, recently it's gotten popular to refer to this rain as being as strong as battery acid. There really isn't any evidence to suggest that it got that bad, but it sounds good. It's also easy to debunk, so they did that as well.

I could go on, but the bottom line was that it might have been an accumulation of events that did the dinosaurs in: Climate change, volcanism, meteor impact(s), and so on. Well, that's not a new idea. Frankly, many people have thought that the meteor is what finished off the dinosaurs, but it didn't do the bulk of the damage. It was just the straw that broke the velociraptor's back.

And they didn't mention Alvarez once during the whole program. For which Alvarez is probably grateful.