Hold Up The Sky

by Liu Cixin

  Below the astronaut, the shuttle was gradually drawing away from the mirror and had to constantly run its engines and thrusters to maintain proximity. However, due to its trajectory its drift was accelerating, and before long such adjustments would be impossible. A second encounter would require waiting an entire orbit, but would the mirror still be there? With this in mind, the astronaut made a decision. He switched on his thrusters and headed straight into the mirror.

  His reflection loomed large, filling his field of vision with the quicksilver bubble of his helmet’s one-way reflective faceplate. He fought to keep from closing his eyes as his head touched the mirror. At contact he felt nothing, but in that very moment everything vanished before his eyes, replaced by the darkness of space and the familiar Milky Way. He jerked around, and below him was the same view of the galaxy, with one addition: his own reflection receding into the distance, the maneuvering units he and his reflection wore linked by streams of thruster jet fog.

  He had crossed the mirror, and the other side of it was a mirror, too.

  His earpiece had been chirping with the commander’s voice when he was approaching the mirror, but it had cut out. The mirror blocked radio waves. Worse, the Earth wasn’t visible from this side. Surrounded entirely by stars gave the astronaut the feeling of being isolated in a different world, and he began to panic. He adjusted the jets and arrested his outward motion. He had passed through the first time with his body parallel to the mirror, but now he oriented himself perpendicular, as if diving headfirst into it. Just before contact, he cut his speed. Then the top of his head touched the top of his reflection, and then he passed through and saw with relief the blue Earth below him, and heard the commander’s voice in his ear.

  Once his upper torso was through he dropped his drift speed, leaving the remainder of his body on the other side. Then he reversed the direction of his jets and began to back up; fog from the jets on the opposite side of the mirror issued from the surface around him like steam rising from a lake in which he was partially submerged. When the surface reached his nose, he made another startling discovery: The mirror passed through his faceplate and filled the crescent space between it and his face. He looked downward and saw his frightened pupils reflected in the crescent. No doubt the mirror was passing through his entire head, but he felt nothing. He reduced his speed to the absolute minimum, no faster than the tick of a second hand, and advanced millimeter by millimeter until the mirror bisected his pupils and vanished.

  Everything was back to normal: Earth’s blue sphere on one side, the glittering Milky Way on the other. But that familiar world persisted only for a second or two. He couldn’t reduce his speed to zero, so before long the mirror was above his eyes, and the Earth vanished, leaving only the Milky Way. Above him, the mirror blocking his view of Earth extending hundreds of thousands of kilometers into the distance. The angle of reflection distorted his view of the stars into a silver halo on the mirror’s surface. He reversed thrusters and drifted back, and the mirror dropped down across his eyes, vanishing momentarily as it passed to reveal both Earth and Milky Way before the galaxy vanished and the halo turned blue on the mirror’s surface. He moved slowly back and forth several times, and as his pupils oscillated on either side, he felt like he was passing across a membrane between two worlds. At last he managed a fairly lengthy pause with the mirror invisible at the center of his pupils. He opened his eyes wide for a glimpse of a line at its position, but he saw nothing.

  “The thing’s got no width!” he exclaimed.

  “Maybe it’s only a few atoms thick, so you just can’t see it. Maybe it approached Earth edgewise and that’s why it arrived undetected.” That was the assessment of the shuttle crew, who were watching the images sent back.

  The astonishing thing was that the mirror, perhaps just atoms thick but over a hundred Pacific Oceans in area, was so flat as to be invisible from a parallel vantage point; in classical geometry, it was an ideal plane.

  Its absolute flatness explained its absolute smoothness. It was an ideal mirror.

  A sense of isolation replaced the astronauts’ shock and fear. The mirror made the universe strange and rendered them a group of newborn babes abandoned in a new, unfathomable world.

  Then the mirror spoke.

  THE MUSICIAN

  “I am a musician,” it said. “I am a musician.”

  The pleasing voice resounding through space was audible to all. In an instant, all sleepers on Earth awoke, and all those already awake froze like statues.

  The mirror continued, “Below I see a concert whose audience members are capable of representing the planet’s civilization. Do you wish to speak with me?”

  The national leaders looked to the secretary general, who was momentarily at a loss for words.

  “I have something to say,” the mirror said.

  “Can you hear us?” the secretary general ventured.

  The mirror answered immediately, “Of course I can. I could distinguish the voice of every bacterium on the world below me, if I wanted to. I perceive things differently from you. I can observe the rotation of every atom simultaneously. My perception encompasses temporal dimensions: I can witness the entire history of a thing all at once. You only see cross sections, but I see all.”

  “How are we hearing your voice?” the US president asked.

  “I am emitting superstring waves into your atmosphere.”

  “Superstring waves?”

  “A strong interactive force released from an atomic nucleus. It excites your atmosphere like a giant hand beating a drum. That’s how you hear me.”

  “Where do you come from?” the secretary general asked.

  “I am a mirror drifting through the universe. I originate so far away in both time and space it is meaningless to speak of it.”

  “How did you learn English?”

  “I said that I see all. I should note that I’m speaking English because most of the audience at this concert was conversing in that language, not because I believe any ethnic group on the world below is superior to any other. It’s all I can do when there’s no global common tongue.”

  “We do have a world language, but it is little used.”

  “Your world language? Less an effort toward world unity than a classic expression of chauvinism. Why should a world language be Latinate rather than based on some other language family?”

  This caused a commotion among the world leaders, who whispered nervously to each other.

  “We’re surprised at your understanding of Earth culture,” the secretary general said earnestly.

  “I see all. Besides, a thorough understanding of a speck of dust isn’t hard.”

  The US president looked up at the sky and said, “Are you referring to the Earth? You may be bigger, but on a cosmic scale you’re on the same order as the Earth. You’re a speck of dust, too.”

  “You’re less than dust,” the mirror said. “A long, long time ago I used to be dust, but now I’m just a mirror.”

  “Are you an individual or a collective?” the Chinese president asked.

  “That question is meaningless. When a civilization travels far enough on the road of time, individual and collective both disappear.”

  “Is a mirror your intrinsic form, or one of your many expressions?” the UK prime minister asked.

  The secretary general added, “In other words, are you deliberately exhibiting this form for our benefit?”

  “This question is also meaningless. When a civilization travels far enough on the road of time, form and content both disappear.”

  “We don’t understand your answers to the last two questions,” the US president said.

  The mirror said nothing.

  Then the secretary general asked the key question: “Why have you come to the solar system?”

  “I am a musician. A concert is being held here.”

  “Excellent,” the secretary general said with a nod. “And humanity is the audience?”

  “M
y audience is the entire universe, even if it will be a century before the nearest civilized world hears my playing.”

  “Playing? Where’s your instrument?” Richard Clayderman asked from the stage.

  They realized the reflected Earth covering most of the sky had begun to slip swiftly toward the east. The change was frightening, like the sky falling, and a few people on the lawn involuntarily buried their head in their hands. Soon the reflection’s edge dipped below the horizon, but at practically the same time, everything turned hazy in a sudden bright light. When sight returned, they saw the sun sitting smack in the middle of the sky right where the reflected Earth had been. Brilliant sunlight illuminated their surroundings under a brilliant blue sky that had replaced the black night. The oceans of the reflected Earth blended with the blue of the sky so the land seemed like a patch of clouds. They stared in shock at the change, but then a word from the secretary general explained the change that had taken place.

  “The mirror tilted.”

  Indeed, the huge mirror had tilted in space, drawing the sun into the reflection and casting its light onto the Earth’s nighttime side.

  “It rotates fast!” the Chinese president said.

  The secretary general nodded. “Yes, and at that size, the edges must be nearing the speed of light!”

  “No physical object can tolerate the stresses from that rotation. It’s a field, like our astronaut demonstrated. Near-light-speed motion is entirely normal for a field,” the US president said.

  Then the mirror spoke: “This is my instrument. I am a star player. My instrument is the sun!”

  These grand words silenced them all, and they stared mutely at the reflected sun for a long while before someone asked, their voice trembling with awe, how it was played.

  “You’re all aware that many of the instruments you play have a sound chamber whose thin walls reflect and confine sound waves, allowing them to resonate and produce pleasing sounds. In the case of EM waves, the chamber is a star—it may lack visible walls, but it has a transmission speed gradient that reflects and refracts the waves, confining them to produce EM resonance and play beautiful music.”

  “What does this instrument sound like?” Clayderman asked the sky.

  “Nine minutes ago, I played tuning notes on the sun. The instrument’s sound is now being transmitted at the speed of light. Of course, it’s in EM form, but I can convert it to sound in your atmosphere through superstring waves. Listen….”

  They heard a few delicate, sustained notes, similar to those of a piano, but with a magic that held everyone momentarily under its spell.

  “How does the sound make you feel?” the secretary general asked the Chinese president.

  “Like the whole universe is a huge palace, one that’s twenty billion light-years tall. And the sound fills it completely.”

  “Can you still deny the existence of God after hearing that?” the US president asked.

  The Chinese president eyed him, and said, “The sound comes from the real world. If it can produce such a sound, then God is even less essential.”

  THE BEAT

  “Is the performance about to start?” the secretary general asked.

  “Yes. I’m waiting for the beat,” the mirror replied.

  “The beat?”

  “The beat began four years ago and is being transmitted here at the speed of light.”

  Then there was a fearsome change in the sky. The reflected Earth and sun disappeared, replaced by dancing bright silver ripples that filled the sky, making them feel like Earth had been plunged into an enormous ocean and they were looking up at the blazing sun beyond the water’s surface.

  The mirror explained: “I’m blocking intense radiation from outer space. I can’t totally reflect it, so what you’re seeing is the small portion that gets through. The radiation comes from a star that went supernova four years ago.”

  “Four years ago? That’s Centauri,” someone said.

  “That’s right. Proxima Centauri.”

  “But that star has none of the necessary conditions for supernova,” the Chinese president said.

  “I created the conditions,” the mirror said.

  They realized that when the mirror had said it made preparations for this concert four years ago, it was referring to that event; after selecting the sun as its instrument, it had detonated Proxima Centauri. Judging from the audio test of the sun, it was evidently capable of acting through hyperspace and pulsing the sun 1 AU away. But whether it possessed the same ability for a star four light-years away remained unknown. The detonation of Proxima Centauri could have been accomplished in one of two ways: from the solar system via hyperspace, or by teleporting to its vicinity, detonating it, and then teleporting back. Both were godlike power, so far as humanity was concerned, and in any case the light from the supernova would still take four years to reach to the sun. The mirror said that music it played would be transmitted to the cosmos by EM, so was the speed of light for that hypercivilization akin to the speed of sound for humans? And if light waves were their sound waves, what was light for them? Humanity would never know.

  “Your ability to manipulate the physical world is alarming,” the US president said.

  “Stars are stones in the cosmic desert, the most commonplace of objects in my world. Sometimes I use stars as tools, other times as weapons, and other times as musical instruments…. I’ve turned Proxima Centauri into a metronome, basically the same as the stones used by your ancestors. We both take advantage of ordinary objects in our world to enlarge and extend our abilities.”

  But the occupants of the lawn could see no similarity between the two, and abandoned the attempt to discuss technology with the mirror. Humanity could no more comprehend it than an ant could understand the ISS.

  Little by little the light in the sky began to dim, giving them the impression that it was moonlight shining on the ocean, not sunlight, and that the supernova was going out.

  The secretary general said, “If the mirror hadn’t blocked the energy from the supernova, the Earth would be a dead planet.”

  By this point the ripples in the sky were gone, and the Earth’s enormous reflection again occupied most of the sky.

  “Where’s the beat?” Clayderman asked. He had left the stage and was sitting among the world leaders.

  “Look to the east!” someone shouted, and they saw in the eastern sky a dividing line, ramrod straight, bisecting the heavens into two distinct images. The reflected Earth, partially cut off, remained on the western side, but in the east was a dazzling starfield that many of them knew was the correct one for the northern hemisphere rather than the reflected southern sky. The division line marched west, enlarging the starry sky and wiping out the reflected Earth.

  “It’s flying away!” shouted the secretary general. And they realized he was right: the mirror was leaving the space over Earth. Its edge soon vanished beneath the western horizon, leaving them standing beneath the stars of an ordinary sky. It did not reappear—perhaps it had flown off to the vicinity of its sun instrument.

  It comforted them somewhat to see the familiar world, the stars and city lights as they had been, and to smell the blossoms wafting over the lawn.

  Then came the beat.

  Day arrived without warning with a sudden blue sky and blazing sunlight that flooded the land and lit up their surroundings with brilliant light. But daytime lasted but a second before extinguishing into renewed night as stars and city lights returned. And the night lasted only a second before day returned, only for a second, and then it was night again. Day, and then night, then day, then night … like a pulse, or as if the world were a projector switching back and forth between two slides.

  A beat formed out of night and day.

  They looked up and saw the flashing star, now just a blinding, dimensionless point of light in space. “A pulsar,” said the Chinese president.

  The remains of a supernova, a whirling neutron star, the naked hot spot on its dense surfa
ce turning it into a cosmic lighthouse, its revolution sweeping the beam emitted by its hot spot through space, and giving Earth a brief moment of daytime as it swept past the solar system.

  “I seem to recall,” the secretary general said, “that a pulsar’s frequency is far faster than this. And it doesn’t emit visible light.”

  Shielding his eyes with a hand and struggling to adjust to the crazy rhythm of the world, the US president said, “The high frequency is because the neutron star retains the former star’s angular momentum. The mirror may be able to somehow drain that momentum. As for visible light … do you really think that’s something the mirror can’t do?”

  “There’s another thing,” the Chinese president said. “There’s no reason to believe that the pace of life for all beings in the universe is like that of humanity. The beat for their music might be on a completely different frequency. The mirror’s normal beat, for example, may be faster than even our fastest computers.”

  “Yes,” the US president said, nodding. “And there’s no reason to believe that what they perceive as visible light is the same EM spectrum.”

  “So you’re saying that the mirror’s music is benchmarked to human senses?” the secretary general asked in surprise.

  The Chinese president shook his head. “I don’t know. But it’s got to be based on something.”

  The pulsar’s powerful beam swept across the empty sky like a four-trillion-kilometer-long baton, still growing at the speed of light. At this end, played on the sun by the mirror’s invisible fingers and transmitted to the cosmos at the speed of light, the sun concert began.

  SUN MUSIC

  A rustle like radio jamming or the endless pounding of waves on sand occasionally offered up hints of a vast desolation within its more abundant chaos and disorder. The sound went on for more than ten minutes without changing.

  The Russian president broke the silence: “Like I said, we can’t understand their music.”