by Shain Carter
Becker shook his head vigorously. “Oh sure, that’s the conventional theory, but in this case the conventional theory is wrong.”
Alec looked from Becker to Meredith. “What are you talking about?” he asked in his soft brogue.
“It has to do with a strange deposit of uranium ore found in Oklo,” Meredith told them. She explained that uranium ore contains two different types of uranium atoms, U-235 and U-238. They behave the same in most ways, except that one type is radioactive and the other is not. In nature, the radioactive form - U-235 - decays by splitting into several smaller pieces, including two or three neutrons. This is a very slow process, requiring thousands of years for even the smallest detectable fraction of U-235 to decay. But it does decay.
Because of this decay, the balance between the radioactive uranium atoms and the non-radioactive uranium atoms in uranium ore is not constant with time. The amount of U-235 continually decreases while U-238 levels remain constant. Today only about three-quarters of one percent of all uranium is U-235, but in the distant past the abundance of this type of uranium was much higher.
While the percent of radioactive uranium in ore changes with time, it should be different from one deposit to another. This is because all of the uranium on earth - throughout the entire solar system, in fact - is believed to have come from a common source, namely, a stellar supernova that occurred long before our solar system formed. The percent of uranium present as U-235 should, therefore, be the same at any given time for all ore deposits everywhere, since all deposits began with the same abundance of U-235 and all have aged for the same amount of time.
Actual measurements have confirmed this is indeed true for ore deposits everywhere. Everywhere, Meredith told them, except in Oklo. There geologists discovered uranium ore with much less of the radioactive U-235 than expected. In some samples as much as half the expected amount was missing. The only reasonable explanation is that something at happened Oklo - and nowhere else - that sped up the natural decay of the U-235 atoms.
“We understand radioactive decay processes very well,” Meredith explained, “and the only thing that can speed them up is neutrons. Under the right conditions, when a neutron strikes a U-235 uranium atom, it causes that atom to decay immediately.”
Neutrons are always present in uranium ore, since they are by-products the U-235 decay process. But these neutrons nearly always escape from the ore without striking another U-235 atom - after all, Meredith reminded them, atoms are extremely small, and there are very few radioactive U-235 "target" atoms to strike since their abundance in the ore is quite low to begin with.
The situation is very different, though, when a large number of radioactive uranium atoms are concentrated in a small region. This condition is referred to as critical mass. Now, rather than escaping, most neutrons strike other U-235 atoms. Once struck, these atoms split, releasing more neutrons. One decay event can cause two or three more, each of which causes an additional two or three events, and so on. In short order a chain reaction begins. As the chain reaction progresses the amount of radioactive uranium decreases more rapidly than normal. Eventually this amount falls below critical mass and the chain reaction stops. The remaining U-235 then decays at the normal rate.
The classic examples of chain reactions, Meredith told them, are nuclear power plants and nuclear bombs. But much slower chain reactions are also possible when the U-235 concentration is just above critical.
Ted, who had been following Meredith’s explanation with obvious fascination, patted his open hand on the table. “So you’re saying that the ore at Oklo naturally went critical sometime in the past, and that’s why the abundance of U-235 is so low there today? That’s amazing - almost unbelievable!”
“Yes, almost,” Meredith agreed, “but it is the only plausible explanation. Today even pure uranium ore won’t go critical because the abundance of U-235 is too low. But a very long time ago, when the abundance of U-235 was higher, that wasn’t the case. There must have been very pure uranium deposits in Gabon - pure enough that the concentration of U-235 was critical, but just barely. It led to a slow runaway reaction that quickly depleted about half the U-235 in the ore. At that point the concentration of U-235 dropped below critical, but the results of this depletion carry through to today.”
Meredith turned to Derek. “Your theory has a problem. Whatever happened at Oklo must have occurred in the very distant past - about two billion years ago. We know that because the abundance of radioactive uranium in ore since then has simply been too low to spontaneously achieve critical mass. Even pure ore could not have gone critical any time in the last two billion years, and in nature there is no pure ore - it’s always contaminated with other materials that dilute the radioactive uranium. Whatever you may want to believe, the Oklo phenomenon could not have occurred sixty-five million years ago.”
Becker smiled patronizingly. “You’re absolutely right on one point, Dr. Nelson. The ore could not have spontaneously gone critical sixty-five million years ago. But I am not saying that it went critical spontaneously. I'm saying it had help.
“What would it take to get the uranium to go critical sixty-five millions years ago? The exact same thing it takes to get it to go critical today - enrichment. The separation and concentration U-235. We do it all the time today, and there’s no reason why dinosaurs could not have done it too, sixty-five million years ago. As much as you don’t want to admit it, the only reasonable explanation for Oklo is that dinosaurs designed, built and operated nuclear reactors there sixty-five million years ago.”
From Meredith’s expression it was obvious that she was not swayed by Becker’s logic. She opened her mouth to respond, but George stopped her. “He is right, of course,” he told her. “Listen, you are the world’s expert at nuclear reactors. You know that there is much more to getting a chain reaction than simply having a high abundance of radioactive uranium. There are issues of neutron absorbers and moderators and reactor reflectors. It takes thousands of highly skilled scientists many years to design and build reactors. Nature cannot do this by accident.”
Meredith was not ready to throw in the towel. She and George began a technical debate over the abundance of various radioactive by-products in the Oklo ore. The argument seemed to hinge on the lack of certain chemical by-products found at Oklo.
Dawson had no interest in even trying to follow their conversation. He had noticed earlier a bar along one wall and discretely walked back to it. He poured himself a glass of whiskey and watched the two go at it.
Meredith was more than holding her own. George constantly referred to several sheets of paper he had pulled from a folder he had brought with him, but Meredith had no problem reciting numbers - and their significance - from memory.
After a few minutes Burt joined Dawson at the bar. "She's sharp, that's for sure,” Burt said quietly as he poured himself some water from a pitcher. "What do you think of her?"
Dawson didn't turn his head, but watched Burt discretely out of the corner of his eye. "I think she has a pretty face, but she’s a little heavy around the hips."
Burt’s hand jerked and he spilled water on the bar top. Even in the dim light Dawson could see his face redden. "That's not what I..." he stammered, mopping up the water with a towel. "I didn’t… Damn it, Dawson, you know what I meant." Burt turned and stomped back to his chair.
So easily flustered, Dawson thought to himself. He felt a smug satisfaction knowing that he still knew exactly which buttons to push to get Burt going.
The debate continued for several more minutes, with neither side willing to give in. Meredith and George were clearly at an impasse, and Dawson, still at the bar, decided to get things moving along.
"I hate to interrupt this enlightening discourse,” he called out loudly, "but as I see it, George, the best you could hope for is to show that something might have happened the way you think it did. There's a big difference between something being possible and it actually happening." He motioned to Derek. "Sur
ely you can do better than this."
"Indeed I can, Professor Jones, indeed I can." As he talked, Derek carefully cleared the laptop from the table. "What I was trying to do up until now was to open your minds to the possibility that there were once intelligent dinosaurs roaming the earth. Obviously, you failed to see things as they are. You're too hung up on what you see as a lack of direct evidence. Of course there's very little direct evidence. Most things are going to disintegrate over sixty-five million years - I already showed you that. Not only that, scientists aren't looking for evidence of intelligent dinosaurs, and when they find it they just explain it away as a natural process, even when the natural process that they invoke seems highly unlikely. Like a huge meteorite strike, or a spontaneous nuclear reactor."
Derek knelt and dragged a box out from under the table. "But what I have in here,” he patted the box, "is proof that there was at least one species of intelligent dinosaur. Solid, rock hard proof." Derek winked to Burt, who chuckled back at him.
As Derek pulled the box onto the table, Burt picked up the remote control unit and pressed a few buttons. The room lights brightened and the drapes pulled back, letting in the late afternoon sun. Derek opened the box and pulled out a large object wrapped in cloth strips.
"Come up here,” he motioned. "You’ll definitely want a close look at this."
Ted leapt out of his seat and raced to the end of the table, nearly knocking Meredith over in the process. The others followed, with Dawson taking up the rear, as Derek began to unwind the cloth. After a few seconds Dawson caught a glimpse of light brown between the windings. “A rock?” he asked in disbelief. “You brought us here to see a rock?”
Derek smiled and continued unwinding, exposing the detailed impressions of small bones.
“It’s … it’s a fossil!” cried Ted. “Those are the leg bones of bird!”
“You’re very close,” Derek said as he struggled with the final few windings. “It’s a dinosaur. A micropachycephalosaurus, to be exact. This fossil dates back almost 65 million years, although it was actually buried in a much lower stratum. Intentionally, I have no doubt.”
With a jerk he pulled the final piece of cloth off the stone, revealing the entire skeleton. Dawson crowded closer, marveling at the delicate features. He had seen dinosaur fossils a few times before, of course, but always from a distance, from the other side of a display case in a museum. Now he was awed by the richness of detail, a richness one could not hope to approach from a distance and through glass.
They all stood in silent wonder, staring at the fossil in Derek’s hands. Suddenly Ted jabbed his finger towards the top of the dinosaur. “What’s that?”
Dawson’s gaze shifted up the rock to where Ted’s finger pointed, just below the creature's skull. A small, cream-white ribbon of compressed powder encircled the animal’s neck. The ribbon was irregular, but roughly oval, nearly three inches across at its widest point and about a quarter inch wide. It was continuous except for one short section that disappeared behind the animal’s neck bones. The ribbon was clearly associated with the fossil, yet at the same time looked entirely out of place.
“What on earth, indeed,” Derek declared with a great deal of self-satisfaction. “That is what you came all this way to see. George didn’t know what to make of it either, when he found it, but he was adroit enough to bring it to me.”
Derek paused, then continued in a low voice. “What it is will change your lives forever.”
Alec looked from Derek to the fossil and back again. “How about cutting the crap and getting to the point. What’s the white stuff?”
“George removed a small sample and had it analyzed. In one word, it’s rutile.”
Dawson, who had been staring transfixed at the ribbon, jerked his head up. “Rutile?” he echoed in disbelief. He quickly regained his composure and continued in a dismissive voice. “You've made a mistake. Retest and you'll find that it's something else.”
“Professor, we have tested and re-tested,” George answered gently, “Powder diffraction, X-Ray fluorescence, infrared spectra - you name it, we tried it. Five different analyses, each in duplicate. Every time the result was the same. Rutile. There is no mistake.”
Dawson looked to the others and was momentarily surprised to see them staring back at him dumbly. Unconsciously Dawson had assumed that they, too, would see the obvious impossibility of what George said.
“I don’t get it,” Alec said bluntly. “What’s rutile?”
“It’s one of two forms of titanium dioxide,” Dawson said. This still got no response from the other scientists. “Rutile is titanium dioxide,” he repeated slowly, as if they had simply not understood his words.
“I’m sorry, Jones,” said Alec, “I still don’t get it.”
“It’s an oxide of titanium,” Dawson paused, then tried one last time. “It’s rust. It’s titanium metal rust.”
Chapter Five
Meredith Nelson was the first to grasp the implications of Dawson’s words.
“It’s titanium rust now,” she said slowly, “but it was once titanium metal? A titanium metal band around this animal’s neck? That can't be possible.”
“Au contraire,” Derek chortled. "Jones will have to agree with me on this one. The only way this fossil could have a ring of titanium rust around its neck now is if it had a ring of titanium metal when it was buried. This fossil proves that some dinosaurs had the technology to refine titanium metal. Now you see why I was so pleased when you mentioned wedding rings earlier, Meredith. It's nearly the same thing, isn't it?"
Meredith shook her head slowly. "I don't know if it is or isn't, but I do know that this animal is too small to have had much of a brain, certainly not enough to be intelligent."
"Of course,” Becker replied, “but it wasn't this species that made the collar. She was no doubt the very dear pet of a larger, much more intelligent dinosaur. The titanium band was decorative, like a wedding ring or a necklace, I think. She must have been very important to have such an ornament. I’d like to think she had a religious significance to her masters. Very similar to the way the Egyptians worshipped cats. Of course, that's just speculation at this point. But we'll know the truth soon enough.”
By now, Ted could scarcely contain himself. Ignoring Derek, he turned to Dawson. “Chemically it may be titanium rust, but how can you be so sure that it started out as titanium metal? Surely there are other explanations. Maybe it was simply a skin marking. The animal could have extracted titanium dioxide from its diet and accumulated it as a white ring around its neck. After all, we accumulate metals in our bodies all the time - iron in our blood, calcium in our bones. No one would suggest that these things were originally made out of iron or calcium metal.”
Dawson shook his head. “Titanium is different from those metals in one important way. We eat iron and calcium salts that dissolve easily in our stomachs and then adsorb into our blood. Solubility is crucial, since dissolution is how we extract these elements from our food and move them around in our bodies. But there are no soluble salts of titanium, not in water anyway. It can be dissolved, true, but only in concentrated sulfuric acid.”
“That’s right,” Derek concurred, “only trace levels of dissolved titanium are found in water. This animal would have had to drink over seventy million gallons of sea water to have extracted enough titanium to form that collar.”
“But if it’s soluble in acid,” Alec suggested, “then couldn’t it have just been extracted directly from titanium containing rocks? If the dinosaur’s stomachs were similar to those of present day reptiles, then they should have been very acidic. This dinosaur could have simply eaten titanium bearing rocks. If I recall correctly, there were some dinosaurs that swallowed rocks to aid digestion. It helped grind food in their stomachs.”
Again, Dawson shook his head. “Stomach acid is hydrochloric acid, not sulfuric acid. Besides, the dinosaur would have needed acidic blood to move dissolved titanium from its stomach to its neck, and ex
cept of a few science fiction movies I’ve seen, I have never heard of an animal with acidic blood.”
“So is he right?” Meredith asked Dawson, motioning towards Derek. “This dinosaur really wore a metal collar? Dinosaurs were really capable of refining titanium sixty-five million years ago?”
“Of course not.”
Dawson wished he was confident as the words sounded, but he could not think of another explanation on the spot. He was acutely aware that the others were waiting for him to continue, to prove Derek wrong. He groped for a flash of inspiration, but it never came. Finally, he shook his head slowly.
“I can’t think of any other way for it to have happened. But this intelligence business, it's just impossible.”
“Impossible?” Derek asked smugly. “Or improbable?”
Dawson reluctantly nodded. “Improbable, impossible - either way I’m not convinced. There were no intelligent dinosaurs, that’s a given. We’re just missing something. But for the sake of argument, let’s say that you’re right. Then I’m still unclear on one very important point. What the hell are we doing here? None of us is a paleontologist. You need to announce your findings and let paleontologists and biologists look at the fossil themselves. They're the ones you need to convince, not us.”
“Oh yes, Doctor Jones, I am well aware of scientific protocol. Months of examining, years of theorizing, decades of debating. The steady plod of something you call the scientific progress. But I have neither the inclination nor the time for such a process because I know in the end they will all be convinced, and much sooner than you might think. You see, I have much stronger proof for my theory. Proof that, I’m sure you’ll agree, is simply out of this world.”
This was apparently another inside joke, because both Burt and George laughed politely. Derek beamed at them, then continued, addressing the others. “You all missed one very important artifact when we were discussing whether any evidence of our existence could survive intact for sixty-five million years. I thought that either Ted or Alec would have come up with it, but it must have gone right over their heads.” Again Burt and George laughed.
