Death's End

The pinnace entered four-dimensional space from a warped point between the two ships. At the tail of the pinnace, the small fusion reactor’s core turned from dim red to a faint blue as its power level increased. This flame, together with the balls of fire in the reactors of the two larger ships, illuminated this world of infinity times infinity. Blue Space and Gravity quickly receded, and as the pinnace sailed deeper into four-dimensional space, the high-dimensional spatial sensation intensified. Although Dr. West had already been to four-dimensional space twice, he exclaimed, “How grand is the spirit that can grasp such a world!”

Lieutenant Zhuo piloted the pinnace using voice commands or by moving the cursor with his gaze—it was a good idea to avoid using hands and risking contact with some sensitive piece of equipment that now lay exposed in four dimensions. To the naked eye, the Ring was still but a barely visible dot, but Zhuo cautiously kept the pinnace flying at a very low speed. Due to the extra unmeasurable dimension, visual judgments of distance were completely unreliable. The Ring might be as far away as an astronomical unit or as close as the pinnace’s bow.

After three hours, the pinnace had already exceeded the previous record of distance sailed from the ships in four-dimensional space. The Ring remained but a dot. Lieutenant Zhuo grew even more cautious and was prepared to decelerate at full power and to change the heading at a moment’s notice. Guan Yifan grew impatient and asked Zhuo to fly faster. Just then, West cried out in surprise.

The Ring turned into a real ring—it just happened. One moment, it was still a dot; the next moment, it was a ring the size of a coin. There was no gradual process of change at all.

“You’ve got to remember that we’re basically blind in the fourth dimension,” Lieutenant Zhuo said. He decreased their speed again.

Two more hours passed. If they were still in three-dimensional space, they would have sailed about two hundred thousand kilometers.

All of a sudden, the coin-sized Ring turned into a gigantic structure. Lieutenant Zhuo banked sharply and barely managed to avoid collision. The pinnace passed through the Ring like an arch in space. The pinnace decelerated, turned around, and came to a stop a short distance from the Ring.

This was the first time humans had come close to a four-dimensional object. Similar to high-dimensional spatial sense, they felt the magnificence of high-dimensional materiality. The Ring was completely sealed, and they could not look inside the band, but they could feel an immense sense of depth and of containment. What they were seeing wasn’t just a Ring, but an infinity of Rings all stacked together in concealment. This sensation of four-dimensionality impressed itself upon the soul, and gave the observers the experience of seeing the mountain contained in a mustard seed described in Buddhist parables.

From up close, the surface of the Ring appeared very different from images taken by the telescope. Instead of a golden yellow light, it gave off a dark copper glow. Those faint etched lines that had looked like circuitry were really lines left by micrometeoroids striking its surface. There was still no evidence of any activity, and it didn’t emit light or other radiation. Looking at the ancient surface of the Ring, all three felt a sense of familiarity. They recalled the destroyed droplets, and then tried to imagine the immense four-dimensional Ring with a mirrorlike smooth surface—it would have been a breathtaking sight.

Following the preestablished plan, Lieutenant Zhuo transmitted a message to the Ring via medium-frequency radio waves. This was a simple bitmap, a bit array that could be interpreted as six lines of dots that formed a sequence of prime numbers: 2, 3, 5, 7, 11, 13.

They weren’t expecting any answers, but an answer arrived immediately, so fast that they couldn’t believe their eyes. The information window hovering in the middle of the pinnace cabin displayed a simple bitmap similar to the one they had sent. It also consisted of six lines portraying the next six prime numbers: 17, 19, 23, 29, 31, 37.

The original plan had intended the hailing message as an experiment; there was no preparation for how to develop further communications. While the three in the pinnace debated what to do, the Ring sent a second bitmap to the pinnace: 1, 3, 5, 7, 11, 13, 1, 4, 2, 1, 5, 9.

Then a third bitmap: 1, 3, 5, 7, 11, 13, 16, 6, 10, 10, 4, 7.

A fourth: 1, 3, 5, 7, 11, 13, 19, 5, 1, 15, 4, 8.

A fifth: 1, 3, 5, 7, 11, 13, 7, 2, 16, 4, 1, 14.

The bitmaps came one after another. The first six numbers in each consisted of the six prime numbers sent by the pinnace as a greeting. As for the next six numbers in each series, both Lieutenant Zhuo and Dr. West turned to Guan Yifan, the scientist. The cosmologist stared at the scrolling numbers in the floating window and shrugged.

“I can’t see any pattern.”