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

Information technology advances in great strides. Except for those lucky enough to climb into management, everyone’s knowledge and skills grow obsolete quickly.

That humans will biologically alter themselves is inevitable, which makes life sciences the most terrifying of the sciences.

You don’t need to pity them. Really, let me tell you: don’t. The reality of the universe is not something to envy.” “Why?” Yifan lifted a hand and pointed at the stars of the galaxy. Then he let the 3G force pull his arm back to this chest. “Darkness. Only darkness.” “You mean the dark forest state?” Guan Yifan shook his head, a gesture that appeared to be a struggle in hypergravity. “For us, the dark forest state is all-important, but it’s just a detail of the cosmos. If you think of the cosmos as a great battlefield, dark forest strikes are nothing more than snipers shooting at the careless — messengers, mess men, etc. In the grand scheme of the battle, they are nothing. You have not seen what a true interstellar war is like.” “Have you?” “We’ve caught a few glimpses. But most things we know are just guesses.… Do you really want to know? The more you possess of this kind of knowledge, the less light remains in your heart.” “My heart is already completely dark. I want to know.” And so, more than six centuries after Luo Ji had fallen through ice into that lake, another dark veil hiding the truth about the universe was lifted before the gaze of one of the only survivors of Earth civilization. Yifan asked, “Why don’t you tell me what the most powerful weapon for a civilization possessing almost infinite technological prowess is? Don’t think of this as a technical question. Think philosophy.” Cheng Xin pondered for a while and then struggled to shake her head. “I don’t know.” “Your experiences should give you a hint.” What had she experienced? She had seen how a cruel attacker could lower the dimensions of space by one and destroy a solar system. What are dimensions? “The universal laws of physics,” Cheng Xin said. “That’s right. The universal laws of physics are the most terrifying weapons, and also the most effective defenses. Whether it’s by the Milky Way or the Andromeda Galaxy, at the scale of the local galactic group or the Virgo Supercluster, those warring civil