K is for the K-Pg Boundary

An image from a simple Google search for “dinosaurs.” From earthspacecircle.

You probably have heard about the asteroid. Big BOOM. You can’t really look at a generic picture of dinosaurs on the Interwebs without seeing them fleeing from hellfire and brimstone. But the asteroid involves two parts. The latter part is what happened after the BOOM, and I’ll tell that story toward the end of the alphabet. You’ll have to guess what letter.

But the first part of the scientific part of the story is how did they know? How could scientists tell that there was a big giant asteroid that eliminated all the dinosaurs? Maybe they could figure out from the fossil record that the dinosaurs disappeared. But how did they know it was caused by an extraterrestrial event? Particularly when the impact crater was, as it turns out, deep under water?

They didn’t know at first. The scientific method triumphed in the end. And fathers and sons.

The Old Ideas of Catastrophe

Before 1980, paleontologists did know that dinosaurs disappeared, around 64 million years ago, in fact. The end of the Cretaceous period was set at 64–and not 100 or 150–precisely because that was when all the dinosaur fossils disappeared.  It was somewhat handy that it happened during a chalky geological period since that made it easy to spot on the sides of cliffs.

The layers of geology. White is the KT boundary. Graphic from geowyoth.

But how? That was actually an exam question in paleontology in 1980, before all the asteroid stuff. Possible causes that research suggested included a worldwide virus in the ferns, a new species of ferns that were full of laxatives, volcanic activity, weather changes, and loss of habitat. The last two are Duh. Of course, weather changes would do it, but what caused the weather changes? What caused the death of the plants and the loss of the habitat? There was even a biblical group which argued that dinosaurs became too sinful.  I’m not kidding.  It was on the exam.

Volcanic activity is always a likely suspect.  Even now,  there’s a guy in India who says it was volcanoes and not the asteroid. Or that the asteroid created volcanoes or something. The thing is finding the Big Reason for the demise of the dinosaurs leads to fame and fortune,  so other scientists still want to get in on the action. 

It didn’t lead to fame and fortune for Luis and Walter Alvarez at first.  It led to arguments and scoffing.

From IMDB.com. A “classic,” aka B movie.

It Came From Outer Space!

It is an unusual story.  Science usually does not advance because a smart guy looks at his kid’s science project and says, “That must have been extraterrestrial.” Or if he does, no one takes him seriously. Not even if they’re a Nobel Prize-winning astrophysicist. And their son is a geologist.

Luis Alvarez won a Nobel for building a hydrogen bubble chamber that discovered resonance states. I don’t know exactly what that means in physics, but it certainly means he understood testing and the scientific method. He has a tiny part in the movie “Oppenheimer” because he was at Berkeley when they were building the you-know-what.

Luis Alvarez and a sciency machine. Photo from wikimedia.

Alvarez’s son, Walter, was was looking at geology in Italy, studying magnetism in ancient rocks. Looking at the composition across the time periods, he noticed–as the story goes–that at the K-T boundary, there was a lot of an element called iridium. Luis pointed out that Iridium is very rare on earth. Guess where it’s not rare? Outer space.

I should interject to explain the whole K-T … K Pg boundary thing. For a long time, they called this boundary “K-T.” K stands for Cretaceous. The Germans use a “K,” so scientists think they sound smarter if they talk like German scientists. Meanwhile, an Italian guy back in 1759 decided to divide all time up into three periods (wasn’t I just talking about the rule of threes yesterday?) All of time, back to the beginning, which in 1759 was “let there be light” and the firmament etc. He helpfully called them One, Two, and Three, or the Primary, Secondary, and Tertiary eras. Quickly, other scientists realized that One and Two weren’t very descriptive, but for a long time, they didn’t know that Tertiary means “three,” so they used it. Now that we have computers, they decided Tertiary isn’t descriptive or German enough, so they’ve reverted to calling the “third period” the Paleogene. Therefore, the boundary isn’t the C-T or the K-T, but now it’s the K-Pg. Why isn’t it the K-P? Don’t ask.

Scientific Method: Hypothesis, Data, Prove, Argue, Lob Insults

Alvarez, father and son, published their findings in a few articles in Science magazine, with titles like “Impact Theory of Mass Extinctions and the Invertebrate Fossil Record,” in the early 1980s. What Luis argued was that there was a statistically significant amount of iridium at the boundary time period and NOT elsewhere. The logical conclusion for finding a lot of an extraterrestrial element was that something very big came from space and hit the earth.

You can’t publish scientific data like this without other scientists reviewing it and arguing with you, making you improve it until it makes sense. These are scientific studies; they explain how, when, where, how much, what, and why. The original article proposed a theory about the asteroid as a likely explanation, although it left open the possibility that there could be other explanations. That’s how the scientific method works. Alvarez found something odd–lots of iridium at one time period–and collected enough information to create a hypothesis.

Two things happened. First, because he was not a geologist himself but an astrophysicist, some scientists ridiculed the theory. Basically, mind your own business. Stick to astrophysics. Nobel Schmobel, you don’t know anything about paleontology, butt out. Because I was around at the time he first made the argument, this reaction was discussed in class. The arguments against him lacking knowledge were not good arguments. The second thing that happened was that some of the newspapers picked up on the idea, and they ran with it. That just made the paleontologists madder because it made them feel their life’s work was a bit of a joke.

There were two good arguments against his theory. One was that the Alvarezes had found most of their data at one site in Italy. That didn’t seem like enough to argue on behalf of a giant megaton asteroid wiping out all life on earth. The second was one that Luis himself wrote in the paper: “Where’s the crater?”

The iridium deposits at the boundary, photo from research-ir.

The antidote for not having enough data was easy. Go get more data. The antidote for the crater was to find it, which they eventually did. The antidote for being told to butt out was a lot more problematic.

Smart People Say Dumb Things

I don’t think Luis was prepared for the level of vitriol that came at him from the paleontologists. And he had won a Nobel prize, so maybe he thought they’d cut him some slack, when they did the opposite. But the other thing was that, being a Nobel prize-winning physicist, he was pretty smart. If you did see “Oppenheimer” or know something about physicists, they are so super smart, and they hear that all the time, that they tend to get a little arrogant.

Alvarez Jr and Sr at the K-PG site, photo from wikipedia.

At one point, he responded to one of the paleontologist’s arguments by saying that they were little than “stamp collectors.” *ouch* In another case, a scientist argued a case in public where some of the data turned out to be misidentified. Alvarez said “It took my son two minutes to demolish” the professor and that the audience “burst out laughing.” Apparently, they didn’t actually burst out laughing, and it seemed like Alvarez himself had become thin-skinned enough to lob a few choice nyaah nyaah nyaahs back.

In 2010, finally, an international group of scientists–experts in paleontology, geology, and other fields–put an end to 30 years of arguing by ruling that an asteroid had indeed struck the earth 65 million years ago. Bad stuff happened after that. Stay tuned for that story.

In the meantime, Luis died in 1988 after a bout with cancer. He lived long enough to see more data captured to support his theory, but not long enough to be vindicated.

Walter Alvarez, the quiet son, started working on a project called “Big History,” giving lectures and producing technology to help people understand the significance of time scales. Some of those lectures are online and free. His reputation survived perhaps, in part, because he didn’t lob insults at people. Frankly, being a scientist son of a Nobel prize winner was probably not the easiest thing in the world.

But if his dad hadn’t taken such an interest in his work, then we’d still think the dinosaurs were just wicked.

Jesus loves the ankylosaurus! Photo from youtube.

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