Dragon's Egg (6 page)

Soon a histogram of pulses versus the direction in the sky flashed on the screen.

“Look at that spike!” Donald said. “Is that the right direction?”

“Mais oui!”
Jacqueline’s fingers stumbled in the excitement, and she had to erase a distorted plot before she slowed down and finally got the computer to show the number of counts versus time when the telescope was pointing in the right direction.

“There they are, just like little soldiers, five times a second!” said Donald.

“5.0183495 times per second,” Jacqueline retorted. “That number is engraved in my memory. What I really hope to get out of this X-ray data is some evidence of delay between the X-ray pulses and the radio pulses. The X-ray pulses will travel at the speed of light, but the radio pulses will be delayed slightly by the interstellar plasma and will arrive later. The more they are delayed, the more plasma they had to travel through. The combination of X-ray data and radio data will give us a rough idea of the distance to the pulsating source.”

As she talked, she was working the keyboard, and soon, underneath the marching row of X-ray spikes, there was a similar row of spikes from the radio antenna.

“It is a good thing you decided to digitalize the radio data sixteen times a second so we could see the individual pulses,” Donald said. “If we had tried four times a second as I recommended, we would have missed most of them.”

“There is no delay!” Jacqueline cried, bewildered.

“Hmmm,” said Donald, “maybe the delay is almost exactly 200 milliseconds and they are just shifted.”

“No,” Jacqueline said, pointing to the screen. “Look—there is a very weak X-ray pulse followed by three strong ones and then two weak ones. You can see the exact pattern in the radio pulses, right below them. The delay is almost zero. That must mean that whatever the source of the pulses, it is very close to the detectors.”

“…  and the closest thing to the detectors is the spacecraft itself,” Donald said. “I am afraid that somehow the spacecraft is putting spikes into both the low frequency radio antenna and the X-ray telescope.”

Jacqueline frowned, then quickly produced two more plots with much larger scales. The pulses were now so close together that they were back to being scruff again. But the scruffy region on the X-ray plot was much shorter than on the radio plot.

“No, it is not the spacecraft,” she said. “Look here, the pulses come and go with time much faster for the X-ray telescope than for the radio antenna. The X-ray telescope has a field of view that is limited to one degree, while the high sensitivity spike in the radio antenna has a beam width of almost three degrees, and these plots are consistent with the width of those patterns.”

“Well, if it isn’t the spacecraft,” said Donald, “then what is it?”

“Give me a few minutes,” she said, and went back to typing on the keyboard.

Donald got up, walked down the hall to the coffee machine and bought them both a cup of coffee. It looked like a long evening ahead. When he returned, she had the X-ray and radio-pulse trains up on the screen again, but now they were blown up so far that only three pulses appeared on the screen.

“There is a very slight time delay,” she said as he walked in. “I wish I could remember the number
density for the interstellar plasma near the sun. I worked out the values for the latest solar wind cycle last month; I will have to go upstairs and look it up.”

She made a hardcopy printout of the graph on the screen, then ran quickly upstairs. Donald followed slowly behind, carrying the two cups of coffee. By the time he made it up the stairs, she had found the number for the interstellar plasma density. She was punching away on her hand calculator when he walked into her office.

“2300 AU!” she exclaimed. “That pulsar is only one-thirtieth of a light year away!”

“A star that close?” Donald asked. “Surely we would have seen it moving across the sky long ago.”

“No,” she said, “a pulsar is a spinning neutron star, and a neutron star is only about twenty kilometers in diameter. Even if the temperature were high, the size of the light-emitting area is so small that we wouldn’t be able to see it unless we looked in just the right place with a very large telescope. But you are right, it is strange that it has not been picked up in one of the sky surveys.”

“If the pulsar is that close, then why didn’t the radio astronomers find the pulses too?” he asked.

“Neutron stars give off their radiation in beams that shoot out from the magnetic poles, and you have to be in the direction of the beam to see the pulses,” she replied. “That is why the spacecraft sees the pulses and we can’t. The spacecraft is up out of the ecliptic by 200 AU and has moved up into the path of the beams.” She walked over to the whiteboard in the office, picked up a colored marker, and started to pace and scribble.

Donald kept silent as slender feet clicked back and forth across the floor in their dress shoes. He waited patiently while long fingers scrawled diagrams and calculations on the board. He watched in admiration as the pretty face puzzled out the complexity of the
mathematical transformation from one set of astrophysical coordinates to another. Five minutes later, he was still admiring Jacqueline from behind when she finally turned and spoke.

“It is up in the northern sky,” she said. “But it is not where we thought it was. Because the neutron star is so close, there is a difference of over five degrees in the angle from the spacecraft to the star and from the earth to the star. No wonder the radio astronomers could not find it. We told them the wrong direction.”

She went over to a star chart on her wall and carefully made a tiny cross. She turned and, with a wry grin on her face, remarked, “And the reason it was never picked up in a sky survey is that it is right next to Giansar, the fourth magnitude star right at the end of Draco, the Dragon constellation. It would take a good telescope to see the neutron star image in that bright glare.”

She drank down the rest of her coffee.

“Let’s go wake up old Saw-face,” she said. “We’ve got a paper to publish.”

In two days the paper was prepared and accepted into the
Astrophysical Letters
computer. The next day it was on the astrophysical information net, along with a note from the radio astronomers that very weak 199-millisecond pulsations had been detected from a region in the northern skies right at the end of the constellation of Draco. Shortly thereafter, the new ten-meter telescope in China found a faint speck in the sky, and pictures of “The Egg of the Dragon—Sol’s Nearest Neighbor” appeared in
Sinica Astrophysica
. The popular press copied the picture—along with the picturesque Chinese name, and soon people were peering up at the night sky, vainly trying to catch a glimpse of “Dragon’s
Egg,” resting just off the end of the constellation Draco, as if the star were a recently laid egg.

It was Saturday evening. Donald and Jacqueline sat on the grass of the Griffith Observatory and talked. They were much more relaxed than they had been for months. Jacqueline’s thesis was completed, and her formal oral defense the day before had been a mere formality, what with the world-wide scientific acclaim and video-news publicity being made over the discovery.

“I still don’t understand why Sawlinski is doing the video-news interviews,” Donald said with a frown. “You were the one who discovered the neutron star first, not he.”

“That is not the way science works,” Jacqueline explained. “A Professor starts a research project hoping to discover something new. The student sometimes makes the discovery, but without the Professor’s research project, the discovery would not have been made. Since the Professor gets the blame if the project is a failure, he should get the benefit from any successes. Besides, it doesn’t upset me—after all, my career is off to a great start!”

Donald only felt a greater admiration for the woman of whom he had become so fond. He kept silent and continued to look upward at the stars.

After a long time, Jacqueline spoke. “I wonder if we could ever go visit Dragon’s Egg. At the speed it is traveling, it will be gone from the Solar System in a few hundred years. I wish I could go myself, but I guess maybe it will be my grandchild or great-grandchild.”

“We may be going sooner than you think,” Donald said. “The latest news on the Nigerian magnetic monopole discovery is that they have used the first monopole
in a large magnetic accelerator to generate other monopoles, and some of those have already been used as a catalyst for a deuterium fusion reaction. The JPL engineers are excited about the fusion results. They are already starting to design fusion-rocket concepts for interstellar spacecraft. I don’t think a ship will be ready soon enough so that you and I could go for a visit, but I wouldn’t be surprised if, in twenty or thirty years, one of our children will be looking down at Dragon’s Egg from a close orbit.”

And inevitably, the years passed …

Quick-Mover was getting tired. He only hoped the Swift was tiring faster. The Swift was much quieter than he, but its brain was slow, and it never seemed to learn from its repeated failures to catch him. This particular beast had been harassing his clan for the last three turns of the sky, and the clan had been forced to retreat to a cluster of boulders that blocked the Swift’s rush. There was nothing they could do until the huge beast tired and went away, or else caught one of them out in the open—like Quick-Mover—who was now beginning to regret his attempt to get a food-pod from a nearby plant.

He watched carefully with six of his eyes as the Swift laboriously moved in the hard direction until it figured it was directly east or west of its intended prey. Once there, it would start accelerating, swiftly slithering toward him as its long narrow body twisted across the crust. As it neared, the great, glowing maw would open, and out from under each of the five eyes ringing the gaping mouth would spring a long, sharp fang of crystal.

Quick-Mover knew how sharp those fangs were, since he had one stored in a tool pouch in his body. He had
retrieved the fang from the mangled carcass of a Swift that had been the loser in a mating duel and had used it to cut up the drying carrion that he and his clan had enjoyed as a supplement to their food-pod diet.

The Swift launched its rush. Quick-Mover waited until the Swift had committed itself to its attack; then, thinning his flexible, opalescent body down, he pushed into the hard direction with all the speed that his muscles could command. The Swift was now moving so rapidly that it could not change its course, but it was close. One of Quick-Mover’s trailing eyes winced when a fang nicked its thick support stub.

As the Swift slowed its rush and turned to attack again, Quick-Mover became desperate. Soon one of those sharp fangs was going to slash a large hole in him, and the next time the Swift made its rush, it would catch him.

Then suddenly, Quick-Mover had a thought. He had a fang too! He watched the Swift shift position off at a distance and begin its rush. He quickly shaped a section of skin into a short tendril and, reaching into the tool pouch orifice, pulled out the fang. He enlarged the tendril into a strong manipulator, backed up with a thick crystal bone core, and pushed the rest of his body into the hard direction again. This time, he left a portion of his body out in the path of the Swift. It was the thick manipulator holding the fang. Quick-Mover felt a jar, then his eyes glowed as he saw the Swift stumble to a halt, fangs snapping at its flank, where the glowing vital juices poured out onto the crust.

Quick-Mover looked in awe at the fang held in his manipulator. Both were covered with dripping gobs of glowing juice. He sucked them clean, enjoying the unaccustomed taste of fresh juice and meat. He moved over to the still-thrashing Swift. Carefully keeping well off in the hard direction, he watched the Swift as it grew weaker. Finally, feeling bolder, he moved the
manipulator with its fang over the center of the long thin body and struck downward. The sharp point sank deep into the body. The Swift, struck in its brain-knot, shivered and flowed into a fleshy pile.

Quick-Mover raised the fang and struck once more.

It felt good.

He was mightier than a Swift! Never again would one of these beasts terrorize his people!

The fang struck again and again and again …

Pierre Carnot Niven floated in front of the console on the science deck of the interstellar ark, St. George. The thin young man pulled thoughtfully at the corner of his carefully trimmed dark brown beard as he monitored the activities out in the asteroid belt surrounding the still-distant star, Dragon’s Egg.

“It’s still ‘Mother’s Star’ to me,” Pierre thought as he recalled his childhood years, lying in his father’s arms out on the lawn to watch the first interstellar probes go out to explore the neutron star his mother had found.

There had been some whispers of “favoritism” when he had been picked to be Chief Scientist of the Dragon’s Egg exploration crew, but those who whispered had not been as driven as he. He had felt his mother had received too little scientific recognition for her discovery, and his whole life had been spent rectifying that supposed wrong. He had not only made himself the world’s expert on neutron-star physics, but had also taught himself to be a popular science writer so that everyone—not just a few scientists—would know of the accomplishments of the son of Jacqueline Carnot. Pierre had been successful, for his ability to communicate science concepts at every level had led to his being chosen leader and spokesman for the expedition.
Now the talking and selling and explaining were through, and the scientist in Pierre took over.

The expedition was still six months away from Dragon’s Egg, but it was time to start the activities of the automated probes that had been sent ahead by St. George. There would be a lot of work to do in preparation for their close-up view of the star. Now that they had found and identified the asteroidal bodies around the neutron star that they would need, the work could be done as easily by robot brains as human ones.