Death's End

“Be careful of where you move your hands,” Chu Yan said. “You might poke an internal organ—yours or someone else’s—by mistake. But as long as you don’t use too much force, even contact won’t be a big deal. You’ll feel a bit of pain or nausea, and of course there’s the risk of infections. Also, don’t touch or move things unless you know exactly what they are. Everything on the ship is now naked: You might be touching a live wire or heated steam, or even integrated circuits, and cause system malfunctions. Overall, you’re like gods in the three-dimensional world, but you have to get used to being in four-dimensional space before you can use your powers effectively.”

Morovich and Guan quickly learned how to avoid touching inner organs. By moving in a certain direction, they could grasp someone’s hand instead of the bones inside the hand. To touch the bones or organs required exertion in another direction—a direction that didn’t exist in three-dimensional space.

Next, Morovich and Guan discovered something else that excited them: They could see the stars in every direction. They could see the bright glow of the Milky Way extending through the universal eternal night. They knew that they were still inside the ship—none of them wore space suits, and all breathed the air on the ship—but in the fourth dimension, they were exposed to space. All three veteran spacers had performed countless spacewalks, but they had never felt so utterly intimate with space. During spacewalks, they were at least enclosed by space suits, but now, nothing stood between space and them. The ship that revealed infinite details did not shield them from space. In the fourth dimension, the ship lay in parallel with all of space.

The brain that had been adapted from birth to sense and feel three-dimensional space could not handle the infinite information generated by countless details, and initially, information overload threatened to shut down processing. But the brain soon grew used to the four-dimensional environment, and without conscious thought it learned to ignore most details, leaving only the frames around objects.

After the initial vertigo, Morovich and Guan experienced another, even greater shock. Once their attention was no longer completely absorbed by the inexhaustible details of the environment around them, they sensed space itself, or sensed the fourth dimension. Later, people would call this feeling “high-dimensional spatial sense.” For those who had experienced it, high-dimensional spatial sense was hard to convey in words. They often tried to explain it this way: Concepts like “vastness” or “boundlessness” in three-dimensional space were replicated an infinite number of times in four-dimensional space in a direction that did not exist in three-dimensional space. They often resorted to the analogy of two mirrors facing each other: In either mirror one could see a boundless multitude of replicated mirrors, a hall of mirrors that extended into infinity. In this analogy, each mirror in the hall was a three-dimensional space. In other words, the vastness that one experienced in three-dimensional space was but a cross-section of the vastness of four-dimensional space. The difficulty of describing high-dimensional spatial sense lay in the fact that for observers situated in four-dimensional space, the space they could see was empty and uniform, but there was a depth to it that could not be captured by language. This depth was not a matter of distance: It was bound up in every point in space. Guan Yifan’s exclamation later became a classic quote:

“A bottomless abyss exists in every inch.”

The experience of high-dimensional spatial sense was a spiritual baptism. In one moment, concepts like freedom, openness, profundity, and infinity all gained brand-new meanings.

Chu Yan said, “We should return. The warped points remain stable for only a brief period of time before drifting away or disappearing. To find a new warped point requires moving in four-dimensional space. That’s a dangerous undertaking for novices like you.”

“How does one find a warped point in four-dimensional space?” Morovich asked.

“Simple. A warped point is usually spherical. Light is refracted inside the sphere, and objects inside are distorted, causing a visual break in the image of the objects. Of course, this is just an optical effect in four-dimensional space, not a real change in the shapes of the objects. Look over there—”