Who actually sent the dark forest broadcast?
The broadcast that exposed Trisolaris to the universe was sent by the crews of two human deep-space ships, Gravity and Blue Space — not by Earth. Earth's own dark forest deterrence collapsed within minutes of Cheng Xin becoming Swordholder, when Trisolaran probes destroyed the gravitational-wave transmitters on Earth. The button Earth could not press was pressed instead by a ship humanity had branded as criminals, four light-years away.
Why did Earth's deterrence fail so fast?
The whole system rested on one person. The Swordholder held a single switch that would broadcast the coordinates of both Trisolaris and the Sun, guaranteeing mutual destruction. For decades, Trisolaris did not dare test whether he would use it.
The handover broke it. Trisolaris gambled that Cheng Xin would not press the switch, and they were right. Their probes struck almost the instant she took the staff, and Earth's gravitational-wave antennas were destroyed in roughly fifteen minutes. Earth lost its ability to broadcast anything, and that path was permanently closed.
Where did Gravity get the ability to broadcast?
Gravity carried the same gravitational-wave antenna technology that Earth's transmitters used. It had been built as a pursuit ship: after Blue Space's flight into deep space during the Doomsday-era exodus, the crew of Blue Space was blamed for the killings of the "Battle of Darkness," and Earth dispatched Gravity — equipped with a working broadcast antenna — to hunt them down and bring them to trial.
That pursuit ship is the twist. The universe-wide broadcast capability that deterrence depended on existed in two places, not one: on Earth, and aboard Gravity, drifting light-years away and largely forgotten. When the two ships finally converged, the hunter and the hunted made the decision Earth could not. They activated the broadcast and sent Trisolaris's coordinates — along with the Sun's — into the cosmos.
What did the broadcast trigger?
Two death sentences. Within a few years, Trisolaris drew its hunter: a photoid moving at near light speed punched straight through its star, and the triple-star system that had tormented Trisolaris for ages was annihilated in a single dark forest strike. The Solar System was exposed by the same broadcast; its own strike came later, when a dimensional foil flattened the system into two dimensions.
The same act that freed humanity from Trisolaran occupation also marked the Solar System for death — and the hand on the trigger belonged not to Earth's chosen Swordholder, but to the exiles Earth had condemned. That is the coldest edge of the dark forest: survival and annihilation were the same button, pressed by the people the rules had cast out.