Quickies

Skepchick Quickies 11.23

Amanda

Amanda is a science grad student in Boston whose favorite pastimes are having friendly debates and running amok.

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  1. Bill Nye garbled the history of the K-T event quite a bit. The evidence of the Chicxulub crater was discovered first. by oil exploration geologists, but the data was never published and the significance of it wasn’t realized, until long after the discovery of the iridium layer at the K-T boundary. Nye’s sequence was 1) discovery of the sudden dinosaur extinction at the K-T boundary, 2) discovery of the Chicxulub crater, 3) attribution of the extinction to the impact, 4) discovery of iridium layer confirming it all. The actual sequence was 1) discovery of the dinosaur extinction, 2) discovery of the iridium layer, which led to 3) hypothesis that a large meteorite impact had caused a global winter which killed the dinosaurs and many other large animals, and then 4) discovery of the Chicxulub crater at the right age and place.

    Many side notes: The iridium layer is world-wide (it was discovered in Italy), but is thickest in North America, indicating the the impact is in the vicinity. Iridium is very rare in the Earth’s crust, about 1 part per billion. The iridium layer is about 30 times richer in iridium, so it is still very rare. It’s not like a sheet of iridium foil separating the K from the T! It’s a layer of clay with elevated iridium levels. Iridium is much more common in meteorites, which is what leads from “iridium layer” to “extraterrestrial impact”. The work that led from “impact” to “extinction” was based on the global cooling/nuclear winter models which were in turn based on the observations of global cooling on Mars. and subsequent modeling, seen when the Viking landers arrived in 1975. (There was a Martian global dust storm in progress at the time. Such storms were previously unknown.)

    One of the principle objections to the impact hypothesis was “Where is the crater?”

    Cores drilled in the Yucatan in the 1970s showed shocked quartz, tektites and the kind of jumbling associated with impact craters, though no crater was visible from the surface. When a geologist was looking at the data later, he discovered the debris was 65 million years old, which was the right age for the K-T event.

    So it was the crater that confirmed the iridium, not the other way around.

    BTW, the only info I could find about Bill’s status is that he was suffering from exhaustion and should be fine, but that was a week ago. Get well, Bill!

  2. It looks like they have removed his video from their website. I’d say he’s not shilling for them any more but he hasn’t released anything to counter the damage he has done.

    David Cammeigh cracks me up, it’s not often you see the mysticism garbage, all the worlds religions are one shtick combined with such blatant racism.

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