Yevgeny turned off the buggy's power and everything went dark save for the brilliant canopy of stars over the black sky. He switched on the lamp attached to his helmet.
"No, leave it dark for a little while,” said Arthur, staring up at the heavens. “I want to look at the stars."
Yevgeny turned off the light. “You have Russian soul."
Arthur scanned the sky in the eerie silence broken only by the soft hiss of the radio and the sound of his own breathing. “Beautiful,” he said after a minute or so when his eyes had dark-adapted. “I've never seen so many stars."
"They not look real,” said Yevgeny. “Stars should—what is word?—twinkle."
"Without an atmosphere,” said Arthur, “the stars do look artificial. It's like a planetarium. A planetarium sky without the music.” He imagined the music: grand, stately, lush, and expansive.
He'd been watching the stars since he was a small boy—since his father had first fired his imagination with the grandeur of the universe. Arthur bit his lip; he was just deferring the inevitable. He lowered his eyes, paused for a moment to gaze at the distant, blinking, red signal light on the lunar lander, then turned and switched on his helmet lamp. “Okay, Zhenya. Let's go."
Yevgeny switched on his lamp and walked toward the long-dormant moon buggy. He gave the vehicle a quick examination, then canted his head downward so the lamp illuminated the ground. “Hah!” he said. “Footprint. Look."
Arthur bounded over, carefully avoiding stepping on the footprints that surely must have been his father's. The single set of tracks led off toward the crater wall. He threw a nod to Yevgeny and the two of them began following the footprints.
Within five minutes, they had followed the trail almost up to the wall of the crater.
"I not see any return tracks,” said Yevgeny.
"He must have walked alongside the wall for some reason."
"Bozhe moi!" said Yevgeny in a startled voice as he played the beam of his lamp along the crater wall. “What that?"
The beam moved along the wall, disappeared, and then reappeared.
"An opening in the wall?” said Arthur. “Strange."
Yevgeny loped forward. "Da! Strange. Lava tube, maybe."
Arthur joined Yevgeny at the wall and peered into the roughly meter-wide by two-meter-tall void. “I've never heard of lava tubes in crater walls—and certainly not rectangular tubes.” He walked tentatively into the opening and examined the walls. “Smooth,” he said. “It doesn't look natural. It looks almost as if it were constructed. Vertical walls and a flat floor."
"By previous mission, maybe?"
"We weren't briefed about it.” Arthur directed his beam ahead. “And why?” He walked into the cave.
"Wait!” Yevgeny shouted from behind, the shout unnecessary as they communicated by suit radio. “It perhaps dangerous. In fact, definitely dangerous because your..."
"I know,” said Arthur, slowing down but not stopping. “Because my father must have—"
"I think we go back,” said Yevgeny from the cave entrance. “Make report. Wait for instructions from Commander."
"I'll go just a little farther,” said Arthur, straining to see into the void. “Maybe I'll find something to actually report."
"No!” came another voice. Arthur started. It still felt strange that casual talk could travel over radio distances. “No,” the voice repeated, Commander Drummond's voice. “We must assume you are in danger. Return to the lander."
"Yes, sir,” said Yevgeny, quickly, as if by reflex.
Arthur stopped and turned back the way they'd come. But he made no response to Commander Drummond. Yevgeny took a few steps, then swiveled around and looked at Arthur with a curious expression.
Arthur felt torn between his duty to honor Drummond's order and his duty to his father.
"I'm sorry, Zhenya,” he said in Russian after a few seconds. “I've got to see where this tunnel leads.” He turned and continued into the depths of the cave. After a few steps, he looked over his shoulder and saw Yevgeny shrug—obvious even through a spacesuit. Then Yevgeny followed Arthur into the cave.
"Davidson. Report!” came the commander's voice. Arthur ignored it. “Davidson. Zhukov. Report!” Drummond insisted.
Yevgeny caught up, tapped Arthur on the shoulder, and the two of them pressed forward.
After twenty meters or so, the cave sloped downward. Arthur looked back and could no longer see the points of starlight through the opening. They walked on in a silence broken only by Commander Drummond's repeated orders. But as they pressed on and more rock stood between them and the lander, Drummond's radio voice crackled, faded, and finally became inaudible.
"You didn't have to come,” said Arthur once he realized the commander was well out of radio range.
"But I wanted to, my friend.” Yevgeny chuckled. “You are not only one who want adventure."
"Bolshoya spasiba," said Arthur. “I'm really glad you're with me. But we are disobeying a direct order."
"Is Russian system, Generals pretend give orders; we pretend obey them."
* * * *
After about a fifteen-minute walk, the downward slope leveled out and, after a further five minutes, Yevgeny and Arthur emerged from the passageway into a large circular chamber. They scanned the room, their lamps illuminating swaths of the wall and ceiling. By Arthur's estimation, the chamber was forty meters in diameter. The wall, whitish-gray, stood just under two meters high and was topped by a black hemispherical dome. The wall and dome were both smooth but not shiny. In the middle of the room, Arthur could see a pedestal. It looked to be about a meter and a half high.
Arthur, taking in as much of the scene as his lamp allowed, stood open-mouthed.
"This artificial,” said Yevgeny nervously. “Who build it?"
"No one from my country, certainly,” Arthur whispered. He wondered why he felt comparatively calm in the face of this discovery. He should be ricocheting off the walls with excitement. Maybe because the Moon itself is so alien. He took a step forward. “It looks like an abandoned artifact of an ancient civilization."
"I not think abandoned. Your father came here, but not here now.” Yevgeny pressed himself back against the wall. “Maybe they take him,” he whispered. “Maybe they still here."
"Come on, Zhenya. That was almost twenty years ago."
Yevgeny gave a quick, self-deprecating laugh. “Sorry. I—what is phrase?—lost it for moment.” He took a few steps away from the wall, then stopped and looked back. “Maybe we should obey Commander Drummond's orders."
"Yeah, probably,” said Arthur, in a distant voice. He walked toward the pedestal.
The pedestal, round, had a rectangular, gently sloping top like a lectern. As he leaned over it, Arthur saw symbols on the surface and what seemed to be a large push-button with a legend under it. As Yevgeny came close, Arthur studied the symbols.
"I not see any writing like this before,” said Yevgeny.
"Me neither.” Arthur jerked back as the significance hit him. “This isn't an Earth writing system. I'm sure of it.” He turned his helmet to illuminate Yevgeny's faceplate. “Do you know what this means? This place isn't the work of an earlier, advanced Earth civilization. It can't be."
"Why not possible?"
Arthur paused. “Well, maybe it can be. But it's unlikely. Modern man has only existed for thirty or forty thousand years. I can't believe we wouldn't have unearthed artifacts of an advanced civilization.” He paused again. “I'm sure of it.” He glanced once more at the symbols. “This is alien."
Yevgeny nodded.
Arthur regarded the pedestal with a sense of awe. “This is wonderful,” he said. “Even though SETI never found one, I've always believed there were other civilizations in the galaxy.” Almost as an act of faith, he placed a hand over the button and held it there. He more sensed than saw Yevgeny tense up beside him. “Objections?” said Arthur.
Yevgeny didn't answer for a moment. Then he shrugged. "Nyet. No objection."
Arthur pushed down on the button.
The dome filled with stars.
"Jeez!” Arthur gazed upward. The stars shone bright—but they shone blue. “Maybe,” he said, tentatively, “the aliens see white stars as blue."
Yevgeny shook his head. “Is El Greco fallacy."
"What?"
"El Greco was Spanish artist who painted people very thin and tall. Some said that maybe he saw people very thin and tall. But that nonsense. If he look at his own painting, people would look even thinner."
"Maybe the aliens see both white and blue as blue."
Arthur switched off his lamp and took in the blue, starry sky. Yevgeny turned off his lamp as well and the illusion was complete—the night sky viewed through blue-tinted glasses.
"A strange planetarium,” said Yevgeny.
"And it makes no sense,” said Arthur. “A planetarium on the Moon. It's like a zoo in the jungle, or building a swimming pool under water. What's the point?"
Yevgeny gave a short laugh.
"Wait a moment!” said Arthur. “This isn't right.” He scanned the ersatz sky. “I don't recognize this sky."
"You right.” said Yevgeny. “Maybe it sky of alien home planet."
"Could be."
"Arthur, look!” Yevgeny pointed at the pedestal. Where before there had only been a single button, a collection of buttons, what looked like a slider, and a display had risen from the surface, all illuminated in various shades of blue and violet.
"A planetarium, complete with a control panel,” said Arthur at a whisper. “But what is its purpose?" He bent over the panel and tried to comprehend it. But close up, it hurt his eyes. “I bet a lot of this display is radiating in the ultraviolet."
The central display seemed to be a meter of some sort, rich with information; a dark violet vertical bar showed at the far left of the meter and another stood at the far right. A half-height, deep blue bar, apparently a pointer, overlaid the right violet bar. Above each of the two violet bars was a complex, half-centimeter high emblem. Arthur pointed his finger at the one on the left.
"Maybe picture of spaceship.” Yevgeny stared at the icosahedron-shaped insignia.
Arthur nodded, then turned his attention to another section of the panel—a button under which lay a symbol that obviously represented the Earth. On impulse, Arthur pushed the button. Instantly, the blue-green brilliance of the crescent Earth appeared in the sky. But, like the stars, the Earth looked bluer than it should. Arthur smiled with the satisfaction of a control working the way he thought it ought to. He looked back at the stars and bit his lip. “You know,” he said after a few seconds, “maybe the sky is the sky from the Moon, but as it looks either in the far future or in the distant past."
Yevgeny pointed at the little spaceship emblem at the right side of the meter. He tapped on the half-height bar hugging the limit of the display. “Maybe meter represent time, and this when aliens landed on Moon."
"And the sky is as it appeared then?"
"Da," said Yevgeny. “Is possible."
Under the display was a control; it appeared to be a slider. And a row of buttons were directly under the slider. The rightmost button glowed a dark violet. “Ten buttons,” said Arthur. “That suggests the aliens have ten fingers."
"Unless planetarium made for human benefit."
"Hmm.” Arthur glanced at the sky and then back to the panel. “I wonder if their preference for blue and violet indicates their vision peaks in the blue rather than in the yellow, like ours. At any rate, it seems they have eyes."
"And their home star possibly more blue—O or B class. Not G class like Sun."
Arthur placed a hand on the slider. “And from the shapes of the controls, they have hands not all that different in size from ours."
"Unless for our benefit."
"In that case,” said Arthur, “the colors would have been for our benefit as well; we don't see in UV.” He ran a gloved hand softly over the panel. “We're deducing a lot about these aliens of ours."
"Maybe it is test."
"Test?” Arthur smiled. “Fine. Then let's take more of the test.” He tried to move the slider slowly to the right, but it didn't move. He pushed it to the left. Still, it didn't move, but the image of the Earth in the sky began to rotate. Arthur pushed on it harder; the Earth rotated faster and exhibited phases. “Interesting. This control uses force, not displacement."
Arthur started as the Sun, unnaturally bluish, appeared in the sky, illuminating the full extent of the planetarium chamber. Arthur, his eyes dark-adapted, squinted against the brilliance.
Arthur pushed the slider yet harder and the Earth's features blurred to a featureless greenish blue. Day alternated with night every few seconds while the Earth slowly cycled through its phases from Full Earth to New Earth and back. The flickering of the days made Arthur dizzy. He released the control. The flickering stopped with the Sun high in the sky. In the brightness of day, Arthur noticed another button with a bright blue circle displayed below it. Arthur pushed it and the Sun went out.
"Good,” said Yevgeny. “I almost nauseous."
Arthur glanced at the sky. The stars had changed in orientation, but not in position relative to each other. And the pointer still seemed pinned against the right edge of the meter. “This might take a long time."
Yevgeny pointed to the ten buttons. “Maybe they scale multiplier for time."
"Yeah. I bet they are.” The rightmost button was illuminated, so Arthur pushed the leftmost one; it lit while the rightmost button went dark. Again, he pushed the control toward the left. Soon, the stars began to change their positions relative to each other. Arthur gestured to a point in the sky. “That's starting to look like the Big Dipper, isn't it?"
"Da," said Yevgeny. “And that mean sky go forward in time, not backward."
Arthur had his hand pressed against the control when suddenly the stars snapped to an increased brightness. They no longer shone blue, but appeared in their usual colors: mostly white. Arthur, an amateur astronomer, observed that Antares and Betelgeuse were as reddish as usual, and Zubenelgenubi had its expected green tinge.
"This is more like it,” he said. “But everything's stopped.” The Earth had stopped rotating, and he could clearly make out the continents. And the planets had ceased whizzing through the sky. The light went off on the scale-multiplier push button and the rightmost scale-multiplier button began flashing blue.
Arthur pushed harder on the control, but nothing changed—except a label over the control flashed a bright green. He released the control and the lighted label went dark. Peering at the meter-like display, he saw that the pointer stood at about a third of the way from the left violet line.
Yevgeny pointed a gloved finger at that line. “If other line when alien ship first arrive, maybe this line when they come again."
"Maybe,” said Arthur. “I can't seem to advance the stars into the future. The control seems frozen."
Yevgeny laughed. “Maybe now they give harder test."
"But why?” Arthur pushed uselessly at the control. “This sounds really crazy, but what if advancing the stars forward in time advances us too?"
"Agreed,” said Yevgeny. “It crazy—and impossible."
"Why? Going backward in time is maybe impossible, but going forward is okay. If we spent some time very near a black hole, then when we backed away, a lot of time could have passed."
Yevgeny nodded. “I agree. Gell-Mann law say if something not absolutely forbidden by physics, then it must happen. So, not impossible—just very, very improbable."
Arthur studied the control panel. “Maybe the flashing button means we can only use a times-one scale factor.” He looked over his shoulder at Yevgeny. “This is sort of fun. Like learning a language and actually communicating with an alien culture.” He returned his gaze to the panel, stabbed at the button, then pushed the slider control. Nothing happened.
"Maybe you have to hold button down."
Arthur held t
he button down. It stayed illuminated but the flashing stopped.
"And now maybe, push control."
"Okay,” said Arthur. “Here goes.” With a finger still holding down the button, he pushed against the slider with his other hand.
He let go the controls and grabbed the panel with both hands for support. For an instant it seemed the planetarium itself was spinning rapidly in multiple directions at once. Then Yevgeny fell against him. Arthur felt a tide of dizziness, disorientation, and nausea—but a second later, it was over.
"What happen?” said Yevgeny, regaining his footing.
Arthur gazed up at the dome. The stars had moved to later in the lunar day and the disk of the Earth showed a different view.
"I think...” Yevgeny spoke at a whisper. “I think we go back to moon buggy now."
"Yeah.” Arthur glanced back at the entranceway, almost as if checking to make sure it was still there. “Good.” He switched on his helmet lamp and then headed for the entrance, consciously moving at a measured pace to avoid giving evidence of his feeling of subsurface panic.
Yevgeny drew level, then when he'd passed in front of Arthur, he turned back. “You okay?"
"Yeah, fine.” Arthur picked up his pace to match Yevgeny's. “You don't think we might actually have gone into the future, do you?"
"No.” Yevgeny seemed to speak the word without conviction.
Arthur tried to hide his anxiety. “If there's no ship out there,” he said, lightly, “we can go back to the planetarium and step ahead. At some point in the future, there should be a Moon colony."
"I hope there is ship out there,” said Yevgeny, softly, as if to himself.
They walked the rest of the way in silence.
About a quarter of an hour later, Arthur saw the black ahead relieved by a white sprinkle of stars. Rushing to the opening and then through it, he let out a breath as he saw the moon buggy. Then he inhaled sharply and froze; he could see only one buggy.
"It not our buggy,” said Yevgeny, going up to examine it. “It old buggy."
Analog SFF, June 2007 Page 14