He looked changed, almost liberated, as if he’d made a significant decision. Probably he had decided it was time to let it all go. Some people could do that. Jonathan envied people with the ability to make a decision and move on. Yue pressed the button to close the airlock. The pumps started working to evacuate the air from the airlock.
The departure was unspectacular, because they managed to leave on one of the few days where the sun remained hidden below the horizon. Thus, the base lay bathed in darkness. They were already 50 kilometers above the moon’s surface when the sun and Earth appeared over the horizon at the same time. Jonathan immediately turned his eyes away. Having to see his home as a white, shining disk still hurt.
They reached the ARES after 40 minutes. The landing module attached to the ARES so that its drive could accelerate the entire combined spaceship out of lunar orbit. Therefore, to get into the ARES, they’d have to perform a spacewalk, so it was good that they were still wearing their spacesuits.
Judith welcomed them onboard the ARES. She would be their commander for the long flight to Mars. Nobody would be able to have a permanent cabin, because the rotating outer ring only had four sleeping spots, and they’d have to share them on a rotating shift system, in order for all of them to benefit from the simulated gravity out there. Two of the cabins would then be occupied by three astronauts, the other two with two.
Yue and Jonathan would share a cabin. They were the only couple on board. Jonathan had expected Michael to protest, because he would have to sleep in a three-person-shared cabin, but the doctor was probably hoping that Yue would provide the first child for the new branch of humankind. They weren’t planning to oblige him.
One hour later, they met in the command center for the first time as a ten-person crew on the ARES. It was a very tight fit, but because of the zero gravity they could spread out throughout the entire spherical volume of the module. Judith gave a short speech that Jonathan didn’t listen to. He only started paying attention when he heard Michael’s clearly agitated voice.
“We’re not flying directly to Mars?” the doctor asked. “Wasn’t the vote clear enough for you? I demand a direct course or your immediate resignation as commander.”
Now he was showing his true self again. That was fast, Jonathan thought.
Judith remained calm. “You’ve apparently forgotten that our second engine is still attached to the LISA probe. To leave it there and attempt the long journey without an extra propulsion system would be irresponsible, and against NASA regulations.”
“Why didn’t you just say that?” Mike asked loudly.
“Because it seemed obvious to me. I also don’t hear any other objections except for yours.”
“Okay, then. But after we reach LISA, I won’t tolerate any more delays.”
February 10, 2036 – Mars Ship ARES
“There she is,” Atiya said.
“Where?”
“Right there, Jon.” Her finger pointed to a white dot on the screen, which also could have been a star.
“How do you know?” he asked.
“I’ve been watching LISA for months now and recording its data. I think I should know where to find it.”
“When will we reach it?” Jonathan asked.
“In a few hours is my guess. Certainly not before the end of my shift.”
In fact, after three and a half hours, they had moved so close to the central component of the gravitational wave detector that they could fly over to it using their jet backpacks. Jonathan examined it. The probe had an elegant appearance due to its long legs, reminding him of a gazelle.
“So now we go over there, dismantle it, and reattach it to the ARES? How quickly do we start?” Michael asked.
“We will wait for Atiya. As our astronomer, she is the one responsible for the probe.”
“But her sleep shift just started two hours ago,” Michael complained.
“Waiting one more day is not going to make any difference in the end. Or would you be fine with us disassembling your surgical robot while you were sleeping?”
Michael turned around without another word and floated out of the command center.
February 11, 2036 – Mars Ship ARES
As always, the first thing Atiya did was check in on LISA after waking up. The command center was still deserted. Occupying one of the three-person shared cabins had an unexpected advantage—only one other crew member, Kenjiro, was on duty during her awake time, and he was always in the workshop, repairing something.
Atiya let the night’s LISA data run across the screen. It was too bad that it was almost over. Without the propulsion unit, the satellite would drift away from the L1 point, and after at most a few weeks, the lasers would be out of sync and the probe would be unusable. The gravitational wave detector had been a wonder of humankind. There had never been an instrument as sensitive as it on Earth. Together with the Far Side Telescope, they could have formed the basis for truly innovative, groundbreaking science. But it was undeniable that it’d be crazy to try to fly to Mars with only one engine.
Her self-written evaluation software hadn’t found any evidence of significant cosmic events in the new data. That was too bad. It would’ve been nice to have a grand finale. Around 2 o’clock standard time, the instrument appeared to have failed briefly. At that time, the measurement curve had a few holes of a few seconds long. Maybe a cluster of asteroids had moved across the path of the laser beams and blocked them briefly.
Atiya looked at the holes more closely. It was strange that they followed each other in such a regular pattern. The intervals between the holes were exactly as long as the holes themselves. She changed the scale of the diagram. The result was perplexing. What she had thought were holes were large amplitude changes. The measurement values were so far outside the range to be expected for gravitational waves that they could no longer be seen on the figure. What phenomenon could produce such large-amplitude changes? Had a supernova exploded somewhere close by? But the ship itself would’ve certainly detected that. And such a close stellar explosion would have had to be visible in the sky.
She brought up the values from the two legs of LISA separately on the screen. The laser beam to the L4 point had not measured any unusual data, only the one to the reflector on the shell’s surface. A large change in amplitude meant that the reflector had moved away from the LISA satellite and then moved back toward it again. That was a typical effect of gravitational waves that distorted the spacetime fabric. But such a large magnitude change would have had to have been a real tsunami. Such a jolt to space would have had to have affected the ship’s instruments. But there was neither a bright new star in the sky, nor had the spaceship been rattled by any kind of disturbances. So, the measurement had to have some other cause.
There wasn’t anything else she could do. She’d need to look at the raw data. It was, however, a considerable amount of data that would take a while to transfer. Atiya started the download from LISA. The computer would send her a message when all the data had been received.
“So, now, can we finally start with the disassembly?” Michael asked after breakfast.
He was still off-duty, but he wanted to personally make sure that their journey to Mars started as quickly as possible and without any more interruptions. He was not going to be happy with what she was about to say.
Atiya took a deep breath. “We can’t start yet. Right now, I’m downloading data from LISA. Only after I’ve analyzed it can we switch off the satellite.”
“What data are you downloading, and why does Mars have to wait for us any longer? Couldn’t you have done this before?”
“It’s new data, and it’s important.”
“We’re on an important mission,” Michael said. “Judith, say something! Didn’t we decide on the flight to Mars together? I’m starting to think all of you are trying to sabotage the mission!”
Judith set down her closed coffee cup, let go of her croissant, and swallowed. “If Atiya says that it’s importan
t data, then I trust her. She’s the expert.”
“Thank you, Judith,” Atiya said. Her wristband vibrated. That was the signal that she’d been waiting for. “You’ll have to excuse me. My work is calling me.”
“Won’t you at least tell us why the data is so important?” Michael asked, almost in tears.
Atiya floated out of the command center without responding to Michael. She wanted to analyze the data in peace and quiet. The workshop should be ideal for that.
She was in luck. Kenjiro spent almost all his off-duty time at his workstation, but not today, of all days. She had the module entirely to herself. Atiya logged into the computer, retrieved the data from the server, and started the analysis tool. Working with raw data was always a bit cumbersome, because none of the background noise, system interference, or other magnitude swings that could be identified as artifacts had yet been filtered out. But that was the way it had to be. Since she knew the clock time of the magnitude changes, she at least knew where she had to look.
Finally, she had the relevant rows of data on the screen. Gravitational waves had a defined shape, which swelled up and down again. They didn’t suddenly appear and disappear. Their form could even be used to identify their origin.
But in this case, the signal changes could not be assigned to any natural source. In particular, the reflector appeared to have moved in only one direction. She had either discovered a two-dimensional—thus flat—gravitational wave, which would revolutionize physics, or there had been no vibration in the space-time fabric at all, but instead the reflector had somehow been moved physically. However, because it was anchored rigidly in place on the shell, it must’ve been the barrier itself that had moved by less than one millimeter.
What had happened? She couldn’t answer this question by herself. She knew quite a lot about distant celestial objects, but not about the shell that had wrapped itself around the Earth.
“Well, I hope you’ve held us all up for a good reason,” Michael said.
Atiya had been expecting him to complain, but the others were looking at her intently. Their gazes were almost glued to her. They were clearly interested, because she had already revealed that she had news about the shell.
Atiya pulled up the measurement data as a diagram on the large screen. “This is the signal,” she explained. “It’s very clearly regular.”
“It looks as if the shell wants to contact us by simulating a gravitational wave,” Kenjiro said. “Maybe it figured out that we’re listening with LISA?”
“I looked at the raw data,” Atiya said. “The reflector is only moving in the x-axis. A gravitational wave can’t be the cause.”
“Maybe the shell is expanding,” François said. “It’s had enough of the Earth and now wants to envelop the moon too.”
“So why would it first expand and contract a few times? That idea seems too far-fetched to me,” Kenjiro said.
“I’ve got another idea,” Giordano said. “When we were setting up the reflector, I measured how the shell conducted sound. I determined that it’s very thin, and also conducts sound very well.”
“Sound?” Michael asked. “What’s the point? There’s a vacuum all around the shell. You can’t hear anything.”
“Sound is made up of vibrations. They propagate not only in air, but also in water or solid substances,” Giordano explained.
“Like on the shell,” Kenjiro said.
“The vibrations travel radially outward. If such a vibration were to be stimulated directly under the reflector, it would cause the reflector to move back and forth in one axis, just like Atiya measured.”
“And how could such vibrations be stimulated?” Yue asked.
“Assume you’re standing in front of a door and want to go in,” Giordano said.
“Then I’d rip open the door and walk in,” Wayne said, smiling.
“Assume you had some manners.”
“Then I’d knock.”
“That stimulates vibrations in the door,” Giordano said. “The door, in turn, stimulates vibrations in the air on the other side of it so the ear can hear it. These vibrations propagate as sound waves through the room. Here, there’s no air, but there is the reflector, which is moving in sync with the vibrations.”
“You mean someone is knocking from below?” Wayne asked.
“Yes. To me, this looks like an intentional stimulation,” Giordano said.
“And what are they trying to tell us?” Wayne asked.
Atiya’s cheeks started to feel warm. If Giordano was right... She didn’t want to start hoping. It was much too early for that!
She brought up the values again on the screen and played with the time scale until they could see the complete sequence of magnitude changes. There was definitely a rhythm.
“Short... short... short,” she read out loud.
“Long... long... long,” Wayne and Judith said in unison.
“Short... short... short...” nine people on board the Mars ship ARES said together.
February 11, 2036... This date would surely go down in the history of humankind. Atiya pushed off from the computer. She wanted to hug all her colleagues, her friends. Pandemonium broke out in the spherical control center. Nobody was staying in place anymore. They were tumbling around in zero gravity, hugging each other, laughing and crying, screaming and yelling, whooping it up, and Atiya noticed that she felt happy.
It had been a long time since she’d felt like that.
February 12, 2036 – Mars Ship ARES
Did she need to be concerned? Judith fluffed up her pillow and turned it over. Ever since Atiya had deciphered the SOS message yesterday, nobody had seen Michael. He had locked himself in one of the four cabins, so that they had to move the two others sharing his room to the two two-person-shared cabins. Wasn’t he overreacting just a bit? But maybe they just needed to give him some time. It was evident that Michael’s lifelong dream had just been shattered. There hadn’t been a new vote, but everyone had broken out in cheering when they had set the ARES on a course toward the shell.
Naturally they had to respond. The people on Earth were not alone. They had to find a way to restore contact with them. And if Judith was very lucky, she’d be able to speak with Lisa again. A shiver ran up her spine. It was a fantastic discovery, but it also made her afraid. She was most afraid of finding out and having to accept that the most important part of her life, her family, was gone.
There was a knock on her door. Judith looked at the clock. It wasn’t yet time for her to give up the cabin to the next person. Quickly she pulled on a t-shirt. “Come in,” she said.
The door opened slowly. The motion already told her that it must be Yue, Kenjiro, or Jonathan. It was Ken.
“Good morning, Ken.”
“Good morning, Judith. I’m sorry for disturbing you.”
“Don’t be. I know you wouldn’t have awakened me unless it was important. I’ve just been lying here awake, anyway.”
“Are you afraid... of the Earth, I mean?”
“Yes, Kenjiro, I’m afraid. They’ve been sitting in the dark for more than a year. Billions must’ve died.”
“But it’s not the billions that you’re concerned about, right? That’s how I feel, and it’s making me really upset. Isn’t that selfish of me?”
She felt herself drawn to Ken—as a friend. She had so much in common with this Japanese man, even though they’d grown up in very different cultures. Lisa was nothing like him.
“I don’t think it’s selfish, at least, as long as we don’t let ourselves be distracted from the bigger picture,” Judith said. “I would do anything to help the Earth, even if I knew Lisa was no longer alive. Of that I’m sure.”
“That’s exactly why I came to you. I just had a crazy dream, and now that I’m awake, it’s crystallized into a similarly crazy idea.”
“That’s never happened to me.”
“Me either, but there was something different this time. I was walking in a tunnel that kept getting
smaller and smaller. First, I had to hunch over, then I crawled on my knees, and finally I was crawling on my stomach. And then I got stuck.”
“Not a very nice dream.”
“No, not so far. I nearly died. It felt so unfair to me that I decided I would just not let that happen. So, I just stood up. And there was no tunnel there at all. It was just empty, dark space that was pressing down on me.”
“Some spaces can do that to people.”
“Then I woke up. And I could still remember the dream really well. The tunnel that wasn’t a tunnel. Once, back when I was a scientist, I was in a very long tunnel in the particle accelerator at CERN in Switzerland. They generate antimatter there by shooting protons at the heavy metal, iridium. The protons are first accelerated to tremendous velocities in a ring accelerator. That’s not an easy task on Earth, because there must be no interference with the particles when they are in motion. They have to use vacuum-isolated pipes for that.”
“Your tunnel from your dream.”
“Yes and no. If we were to move the process to space, where there is already a vacuum, we could eliminate the tunnel. We could even eliminate the ring. We use a ring on Earth because we don’t have enough room to build a straight acceleration track that’s long enough. But there are many millions of kilometers from the Lagrange points, where we placed LISA, to Earth. We’d only need to accelerate protons to a sufficiently high velocity and have them strike iridium somewhere close to Earth. That would generate antiprotons that are negatively charged. They’d be captured in the solar wind that moves along the Earth’s magnetic field lines. At the poles, the field lines intersect the Earth’s sphere. Anything moving along those lines would strike the shell.”
“So, what would happen with the antiprotons?” Judith already had an idea, but she wanted to try to help Kenjiro refine his idea and thought process.
The Wall: Eternal Day Page 23
