End of an Era

Countdown: 17

Well, what were we to do? I mean, we’d only woken up four hours before; it was hardly time to go to bed. I was too excited to sleep, anyway. I felt light on my feet, almost giddy. After the tyrannosaurs had left, it was so dark that Klicks had turned on the overhead fluorescents. But after a few moments I asked him if he’d mind if I turned them off.

“Ready for beddy-bye so soon?” he said.

“I just want to look at the stars.”

He grunted, but hit the switch himself. It took a while for my eyes to readjust, but soon the heavens were visible to me in all their splendor. In the southwest was a point of light brighter than all others. I thought I knew what it was and fumbled for my 7 x 50s, bringing the dual eyepieces to my face. Yes, the four Galilean satellites were visible, three on the left and one off to the right. The Galilean satellites? Strictly speaking, I was now the first person to see Jupiter’s four largest moons. Maybe we should start calling them the Thackerayan satellites.

The rest of the sky was a mishmash. We’d gone back far enough in time that, even at their indolent pace, the stars had completely reconfigured themselves. None of the familiar constellations were visible. Knowing where the sun had set and where Jupiter was, I extrapolated the ecliptic. Scanning its length, I looked for Jupiter’s siblings.

Venus would have dominated the sky had she been visible. Mars, too, should have been obvious because of its reddish glow. There was a colored point of light about thirty degrees above the horizon, but if anything it was more green than red. Another point shone higher up in the sky—Saturn, perhaps? I brought my binoculars up to check. I couldn’t make out the rings, but that didn’t prove anything. Even Hubble couldn’t see them when they were edge-on.

I lowered the field glasses and simply drank in the night. And, as always of late, my mind wandered to Klicks and Tess.

We hadn’t had much to say to each other lately, Klicks and me. It’s not that there wasn’t a lot I wanted to ask him. I wanted to know how Tess was doing, how their relationship was going, whether they were planning to move in together, how often they—well, a whole bunch of things that weren’t any of my damned business, but that I wondered about anyway.

Klicks and I had been friends, dammit. Good friends. He’d been teaching assistant for Bernstein when I was doing my undergrad at U of T. We’d gotten along great and kept in touch after I’d left for Berkeley to do my graduate work. Years later, when I married Tess in that sprawling ceremony her parents had insisted on, it seemed natural to ask Klicks to be my best man.

May the best man win.

I don’t know if it was just holding in my anger that made me feel congested or whether we’d actually been breathing inside this cramped tin can long enough for the air to begin to run out. Either way, it seemed awfully stuffy. “We’d better open the vents,” I said.

Klicks grunted assent, and we each took hold of one of the red wheels that worked the louvers around the upper edge of the curving outer wall. My ears popped as pressure equalized. Cloying pollens wafted in and I was grateful I’d taken a Seldane before the Throwback.

The night was alive with weird insect sounds: zippings and chirpings and tick-tick-tickings and low, throbbing hums. There was wire mesh over the vents to keep the insects out, but I cringed at the thought of having to face the clouds of prehistoric bugs tomorrow.

“The moon’s coming up,” said Klicks. I turned and looked out the window. Fat and amber, waxing, about three-quarters full, the moon’s pitted face reflected in the still waters of the lake to our south.

“Christ, look at that,” exclaimed Klicks. It took me a moment to figure out exactly what was wrong with the moon’s face. It had turned so that a good part of what was the backside in modern times was clearly visible. I could see some of what must have been Mare Moscoviense on the eastern limb. Librations do let us see a bit of the backside in the twenty-first century, but Moscoviense started at around 140 degrees east latitude, way around back. My first thought was that the moon must not yet be tidally locked, but I rejected that; its orbit was too close for it to be anything but. No, more likely this was the one side that faced Mesozoic Earth. I wondered what had caused Luna to twist in its orbit between now and my time.

“It looks small,” said Klicks.

I thought about that. The moon did indeed seem smaller than normal. That was funny, since we’d assumed it would actually be closer to the Earth now, orbiting objects having a tendency to spiral away slowly over millennia. Still, the moon’s apparent size normally changes by about thirty percent as it moves from perigee to apogee, but most people never notice that; the human eye is notoriously inaccurate at gauging such things. Still, the moon did look small.

Through the binoculars I could see other evidence that this was indeed a younger Luna. I looked at where Giordano Bruno should have been. Normally, that crater is right on the limb of the full moon, but here it should have been well in from the edge of the disk. As I suspected, its series of 500-kilometer-long rays was nowhere to be found. Five British monks in a.d. 1178, their faces tipped toward the heavens, had actually seen the meteor impact that had made that crater.

I thought about mentioning the missing crater to Klicks, but talk of meteor strikes always sparked the debate between us about whether one such had caused the Cretaceous-Tertiary extinctions. Klicks bought that theory. In the eyes of the general public, that made him right in line with mainstream thinking. After all, the newspapers and PBS shows in the 1980s had all concluded that an asteroid impact was indeed the culprit. I wasn’t in the mood to rehash it all again—I’m more inclined to lock horns with Klicks after a few brews, and, sadly, there were none among our provisions—but then something happened that brought up the old debate anyway. Slowly, quietly, without any fuss, a second moon was rising after the first. It was smaller, only about a third the apparent diameter of Luna. Spherical, it too was waxing gibbous, looking like a white jelly bean.

“Klicks?” I said.

“I see it.”

I brought my binoculars to bear on the tiny orb, but its face was too small to show any detail. “Trick,” I said, surprising myself. “I think we should call it Trick.”

“After Charles Trick Currelly, no doubt,” said Klicks, wanting to demonstrate that he got the reference. C. T. Currelly, an early-twentieth-century archaeologist, was the founder of the Royal Ontario Museum, where I worked. One of my occasional forays into the world of popular writing had been a biography of him for Rotunda, the ROM’s member magazine. Klicks did not dispute my choice of name and I was grateful for that small miracle.

We watched the two moons for some time. It seemed that Trick was catching up with Luna, meaning that it was in a much lower orbit. Since Luna is tidally locked, so that the same side always faces Earth, that would mean that Trick probably was also. It must be under a lot of gravitational stress being that much closer…

Aha!

“There goes the periodic extinction theory,” I said, excitement in my voice.

The Alvarez Group at Berkeley published their asteroid-impact extinction theory in Science in 1980. About the same time, an interesting hypothesis was making the rounds concerning the Eocene-Oligocene extinctions, the ones that would come 30 million years after the demise of the dinosaurs. According to it, those later extinctions resulted from a general cooling caused by the breakup of an ancient second moon, leaving Earth with a temporary equatorial ring of orbiting debris that blocked enough sunlight to lower temperatures for a million years or so. The Alvarez theory, sexy because it dealt with dinosaurs and embraced by many pop-science communicators after Sagan had linked it to nuclear winter, eclipsed the ringed-Earth discussions.

Others, including Klicks, tried to push the Alvarez theory a step further, claiming that bolide impacts at regular intervals, caused perhaps by a dark star periodically disturbing either the asteroid belt or the Oort cloud, were responsible for a regular schedule of extinctions, including both the K-T and the E-O. That idea never washed with me, since to get the 26-million-year periodicity you had to use the late Ordovician dyings, which were obviously just the result of plate tectonics moving the supercontinent Gondwanaland over the south pole, causing an ice age.

Klicks knew my position on all of that, of course, so I simply pointed at the second moon. “Trick provides a one-of-a-kind explanation for the Eocene-Oligocene extinctions,” I said. “There’s nothing periodic about a moon breaking up.”

To his credit, Klicks didn’t contest that. But he did say, “Why link it to those deaths? Why not to the ones that are about to occur?”

“Tektites,” I said, referring to the glassy, moon-like rocks found at various locations on Earth. “The age of the southeastern U.S. tektite field coincides with the E-O boundary. I bet they were caused by the impacts of the remnants of Trick.”

Klicks was quiet for a minute or so, although I could hear him grinding his teeth in the dark, the way he does when he’s thinking—chewing over a problem, you might say. Finally he spoke. “We have sleeping pills.”

“Huh?” I guess the change of subject meant I had won that round, but I couldn’t see what he was getting at.

“I said, we could take something to get to sleep. We’re going to be useless in the morning if we stay awake all night.”

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.

Really, many paleontologists see two separate issues. One is what caused the interesting geology at the K-T boundary—there’s a clay layer rich in iridium there. The other is what caused the extinctions. The geology may or may not have anything to do with the dyings.

Klicks believed the asteroid had killed off the dinosaurs; I vehemently disagreed. I wasn’t even convinced that Chicxulub was the source of the iridium layer; like Officer and Drake, I think it’s mostly volcanic in origin. Yes, iridium is rare on the surface of the Earth but plentiful in some kinds of meteors. But Earth does have the same iridium content as most rocky bodies in the solar system; ours is just fractionated into the deep mantle. There’s lots of evidence for volcanism at the end of the Cretaceous. The Deccan Traps in India, for instance, represent at least one million cubic kilometers of basalt that date from the K-T boundary. And volcanic material shows the same concentrations of arsenic and antimony found in the boundary-layer clay, concentrations that are three orders of magnitude greater than what’s normally associated with meteorites.

Indeed, the largest known impact craters on Earth, including the huge crater remnant off Nova Scotia, show no evidence of iridium deposition. Comets, sometimes named as an alternative culprit, are even less likely: there’s no direct evidence at all for iridium in cometary material.

Klicks and I had argued these issues many times in person, in print, and once when I was visiting scholar at the Royal Tyrrell Museum in Alberta, where Klicks worked, on a phone-in show on the local community-access cable-TV channel. Klicks had been adamant during that debate: the impact of an asteroid had killed the dinosaurs. It was clear by the calls we got that those members of the public who didn’t have their own crackpot theories almost exclusively sided with Klicks. They wanted to know what all the fuss was about; hadn’t this issue been settled years ago? Everybody knew an asteroid impact had wiped out the dinosaurs.

Well, we were here.

And we were going to find out, one way or another.

I’ve been keeping this diary for years, and tonight, the most exciting of my life, I’m certainly not going to miss making an entry. Someday perhaps I’ll turn these notes into a book about our voyage (editing out the private stuff, of course), so I think I’ll add a little more background detail than usual.

I typed silently in the dark on my Toshiba palmtop for about an hour, its keyclick shut off and the brightness of its screen turned way down so as not to bother Klicks. When I was done, I swallowed the silver sleeping caplet dry.

Soon morning would be here. Soon we would step out into the Mesozoic.