Because of the speed of light. The known universe is about sixteen billion light-years across, and it’s still expanding. But the speed of light is on… - Liu Cixin

Because of the speed of light. The known universe is about sixteen billion light-years across, and it’s still expanding. But the speed of light is only three hundred thousand kilometers per second, a snail’s pace. This means that light can never go from one end of the universe to the other. Since nothing can move faster than the speed of light, it follows that no information and motive force can go from one end of the universe to the other. If the universe were a person, his neural signals couldn’t cover his entire body; his brain would not know of the existence of his limbs, and his limbs would not know of the existence of the brain. Isn’t that paraplegia? The image in my mind is even worse: The universe is but a corpse puffing up.

"We'll send only a brain," he said.

The past was like a handful of sand you thought you were squeezing tightly, but which had already run out through the cracks between your fingers. Memory was a river that had run dry long ago, leaving only scattered gravel in a lifeless riverbed. He had lived life always looking out for the next thing, and whenever he had gained, he had also lost, leaving him with little in the end.

In this cosmic arena, Luo Ji faced not the fancy moves of Chinese sword fighting, resembling dance more than war; nor the flourishes of Western sword fighting, designed to show off the wielder’s skill; but the fatal blows of Japanese kenjutsu. Real Japanese sword fights often ended after a very brief struggle lasting no more than half a second to two seconds. By the time the swords had clashed but once, one side had already fallen in a pool of blood. But before this moment, the opponents stared at each other like statues, sometimes for as long as ten minutes. During this contest, the swordsman’s weapon wasn’t held by the hands, but by his heart. The heart-sword, transformed through the eyes into the gaze, stabbed into the depths of the enemy’s soul. The real winner was determined during this process: In the silence suspended between the two swordsmen, the blades of their spirits parried and stabbed as soundless claps of thunder. Before a single blow was struck, victory, defeat, life, and death had already been decided.