End of an Era

I never took sleeping pills. I knew I had an addictive personality — another one of Dr. Schroeder’s little insights. That meant messing with any drug would be out of the question for me. Hell, I have a hard enough time avoiding pizza, and Schroeder swears that there’s nothing in the old double-cheese-and-pepperoni that could cause a chemical dependency. Still, what Klicks said made sense. I could hear him moving around the dark cabin. When he opened our medicine refrigerator a small yellow bulb came on, illuminating its interior. Klicks found the bottle he was looking for and, leaving the door open so that he’d have some light, went to the sink and filled a couple of paper cups. We had more than enough water in the tank beneath our feet to last the eighty-seven hours we would be here, that being the maximum length of time the Huang Effect could hold a lock on us when casting this far back.

"Here," he said, offering me one of the Dixie cups and a silver caplet. I slipped the pill into my breast pocket. Klicks kicked the fridge door shut and all was darkness for a moment, until he turned the overheads back on, their brightness making us both squint. He turned the crank on the side of his crash couch, and it ratcheted around from its normal sitting configuration into a flatbed position.

I moved away from the window, from the odd spectacle of Trick slowly chasing Luna through the forest of stars, and converted my couch to sleeping mode, too.

Next, I changed into my pajamas. While doing so, my eyes kept being drawn out the window to the sight of the two

moons. Even if the existence of Trick disproved the periodic extinctions theory, I was sure Klicks would stick to the asteroid model for the death of the dinosaurs.

It’s frustrating being a paleontologist. My neighbor Fred — the one with the dead cat — once said to me, hey, now that they know what killed the dinosaurs, guess your job is pretty much over. That seems to be the public’s attitude. But, really, it’s all because a couple of astronomers and physicists who knew nothing about dinosaurs and a couple of glib talkers from the paleontological community who wanted some limelight pushed the idea so vigorously that it got, quite literally, more popular-press coverage than any scientific theory since World War II.

But it’s just a theory, and not a very good one at that. Yes, there’s no longer much doubt that there was an impact of a ten-kilometer-wide asteroid at or near the end of the Mesozoic. But the Mesozoic lasted 160 million years, and during it there were at least seven other large-asteroid impacts. Each is at least as well documented as the supposed dinosaur-killer (one formed the 100-kilometer-wide Manicouagan crater in Quebec), and there’s zero turmoil in the fossil record associated with any of them.

It’s what Bob Bakker calls the frog problem: frogs, notoriously sensitive to climactic change, survived the end of the age of dinosaurs just fine, but big animals, which should have had more resistance, were all killed off. An asteroid impact is the wrong sort of scenario to explain the selective extinctions we see in the fossil record.

Sure, there’s a buried crater called Chicxulub half on land and half beneath the sea near the northern coast of Yucatan, Mexico. And, yes, by the early 1990s, a series of tests had dated it to very close to the K-T boundary. But with so many confirmed and possible Mesozoic craters, it surprised me that the impact-extinction theory continued to have any legs. Beside Chicxulub and Manicouagan, the later dated at 214 million years before the time I’d been in when I’d woke up this morning, there’s also the 175-million-year-old Puchezh-Katunki crater in Russia, the 145-million-year-old Morokweng crater in South Africa, the 144-million-year-old Mjolnir in the Barents Sea, the 128-million-year-old Tookoonooka in Australia, the 117-million-year-old Carswell in Saskatchewan, and the 74-million-year-old Manson in Iowa. I mean, heck, if large bolide strikes really did have staggering biological effects, we’d have seen a constant series of massive extinctions throughout the age of dinosaurs; it’d be a wonder that the terrible lizards had survived as long as they did.

Nonetheless, to this day, people ask me about the asteroid that killed the dinosaurs. I explain that from time to time the Society of Vertebrate Paleontology surveys its members about the Alvarez theory. The first time such a survey was done, in 1985, only four percent believed that an asteroid impact had caused the extinction of the dinosaurs. In a separate survey in 1991, Mike Brett-Surman at the Smithsonian found those paleontologists who didn’t believe in an impact-extinction correlation outnumbered those who did by four to one. The figure has fluctuated a lot in the intervening two decades, but a show-of-hands at the last SVP meeting indicated support was currently hovering at around twenty percent.