Once, when humankind had been far more naïve, some scientists had believed that it was possible to detect the presence of distant civilizations by astronomical observation: for instance, the absorption spectral signatures of oxygen, carbon dioxide, and water vapor in exoplanetary atmospheres, or electromagnetic emissions. They even came up with whimsical notions like searching for signs of Dyson spheres. But we found ourselves in a universe in which every civilization endeavored to hide itself. If no signs of intelligence could be detected in a solar system from far away, it was possible that it really was desolate, but it was also possible that the civilization there had truly matured.
A safety notice was in reality a universal broadcast as well, and it had to ensure that all listeners would trust its message.
Take a distant star, a barely visible dot. Anyone casually glancing at it would say: Oh, that star is safe; that star will not threaten us. That was what a cosmic safety notice had to accomplish.
Utterly impossible.
Another mystery that no one seemed able to solve: Why wouldn’t Sophon tell humanity how to broadcast such a safety notice?
It was understandable that the survivors of Trisolaran civilization would no longer transfer technology to humanity. After the gravitational wave broadcast, both worlds faced enmity from the entire galaxy, even the entire universe. They were no longer each other’s greatest threats, and the Trisolarans had no time to spare for the Earth. As the Trisolaran Fleet sailed farther away, the connection between the two civilizations grew ever more tenuous. But there was one fact that neither Trisolarans nor humankind could forget: Everything that had happened started with Trisolaris. They were the ones who had initiated the invasion of the Solar System; who had attempted, but failed, to commit genocide. If the Earth managed to make great leaps in technology, revenge was inevitable. Humans were likely to come after whatever new home the surviving Trisolarans found among the stars, and they might complete their revenge before the Earth was destroyed in a dark forest strike.
But a safety notice was different: If such a notice could make the whole universe believe the Earth was harmless, then, by definition, the Earth would be harmless toward the Trisolarans. Wasn’t this just what they wanted?
Although there were no clues for how to send out a true safety notice, and any serious research only confirmed the impossibility of such an endeavor, the public’s yearning for the notice could not be stopped. Although most people understood that none of the existing proposals would work, attempts to implement them never ceased.
A European NGO tried to build an extremely powerful antenna that would take advantage of the Sun’s amplification ability to broadcast their draft version of such a notice. The police stopped them in time. The six droplets in the Solar System had left six years ago, and there were no more blocks on the Sun’s amplification function, but such a transmission would have been extremely dangerous and exposed the Earth’s location even sooner.
Another organization named Green Saviors had several million members. They advocated humanity’s return to an agrarian existence, thereby proclaiming their safety to the universe. About twenty thousand of their members moved to Australia. On this sparsely populated continent where the Great Resettlement was but a memory, they planned to create a model society. The agrarian lives of these Green Saviors were continuously broadcast to the rest of the world. In this age, it was no longer possible to find traditional farming implements, and so the tools they used had to be custom-made with funds from their sponsors. There wasn’t much arable land in Australia, and all of it was devoted to high-end, expensive foods, and so the settlers had to open up new land in desolate areas designated by the government.
It took only one week before these pioneers stopped collective farming. It wasn’t because the Green Saviors were lazy—their enthusiasm alone could have sustained them through some period of diligence—rather, it was because the bodies of modern humans had changed considerably from the past. They were more flexible and agile compared to past generations, but were no longer adapted to boring, repetitious physical labor. And opening up wastelands, even in agrarian times, was an extremely physically demanding task. After the leaders of the Green Saviors suitably expressed their respect for their farming ancestors, the movement dissolved, and the idea of a model agrarian society was abandoned.
