"If I’ve set your imagination going, I apologize." “What do you think I should think about now?” “In my experience, any thinking is liable to go off … - Liu Cixin

In my experience, any thinking is liable to go off the rails. You should just go to sleep.

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.

The aborted research project wasn’t important in and of itself. What mattered was the instruction that Ye Wenjie had given him, so that’s where Luo Ji’s mind was stuck. Over and over again he recalled her words: Suppose a vast number of civilizations are distributed throughout the universe, on the order of the number of detectable stars. Lots and lots of them. The mathematical structure of cosmic sociology is far clearer than that of human sociology. The factors of chaos and randomness in the complex makeups of every civilized society in the universe get filtered out by the immense distance, so those civilizations can act as reference points that are relatively easy to manipulate mathematically. First: Survival is the primary need of civilization. Second: Civilization continuously grows and expands, but the total matter in the universe remains constant. One more thing: To derive a basic picture of cosmic sociology from these two axioms, you need two other important concepts: chains of suspicion and the technological explosion. I’m afraid there won’t be that opportunity.… Well, you might as well just forget I said anything. Either way, I’ve fulfilled my duty.

Of course she's not afraid. She knows that the sun will rise again tomorrow.