The excerpt explains that Trisolaris was destroyed three years and ten months after the Broadcast Era began, far sooner than humanity expected after Gravity sent the gravitational wave broadcast exposing both worlds.

Because Trisolaris had been closely watched, observers recorded extensive data on its extinction. The attack matched the earlier strike on Luo Ji’s 187J3X1: a small near-lightspeed object, a photoid, hit one of the system’s stars, and the resulting stellar explosion annihilated Trisolaris while the planet was near that star.

The timing and trajectory showed that the photoid could not have come from another known star system. Gravity had been three light-years from Trisolaris when it broadcast the coordinates, and the weapon must have launched from an even closer point almost immediately after receiving the broadcast. Since no solar systems existed in that region, observers concluded the attacker had launched the photoid from a spacecraft.

This discovery forces a revision of dark forest theory. The older model assumed exposed worlds were attacked by civilizations based in planetary systems, but mobile alien spacecraft make the threat unpredictable. Humanity knows almost nothing about the number, density, speed, or courses of such vessels.

The excerpt ends by emphasizing that attacks may come much faster than expected. Because unknown alien ships could already be near the Solar System, humanity’s danger shifts from distant and theoretical to immediate.