photoid
Names: photoidphotoids
First appears in Book 2: The Dark Forest, chapter 8 (“Yet its engine lights up. We’ve observed that. When it went out for a second time, Blue Shadow wasn’t close enough to capture an image in time, so we don’t know where the light came from.”)
Appearances
What you know
Book 2: The Dark Forest
- Ch 8A photoid is a tiny object moving near light speed whose relativistic mass reached one-eighth of 187J3X1's, destroying the star on impact.
Book 3: Death's End
- Ch 40The lightspeed object that struck 187J3X1 may be natural, such as a projectile accelerated by the supermassive black hole at the galaxy's center. No second photoid has been detected.
- Ch 42A photoid is a small object traveling near light speed that destroys a star through its relativistically amplified mass.
- Ch 42The photoid that destroyed Trisolaris was launched from a spacecraft, since no other solar systems lie in the region its trail crossed.
- Ch 58A false or real alert claims Observation Unit #1 detected a photoid coming along the ecliptic plane; estimates of its strike time range from hours to a month.
- Ch 59A photoid is a very small, near-lightspeed projectile that damages a star with its enormous kinetic energy from high relativistic mass; it is the most primitive star-attacking weapon.
- Ch 59A photoid collides with sparse atoms and interstellar dust, emitting distinctive radiation from visible light to gamma rays, which can be detected even though the photoid itself is too small to observe directly.
- Ch 59Because a photoid has rest mass it travels slightly slower than light, and gravity curves its path, so its radiation arrives before it does.
- Ch 67Cao Bin says there is no photoid; what they found is 'a slip of paper'.
Key moments
- Book 3 · Ch 42Destruction of Trisolaris
A photoid launched from a nearby spacecraft almost instantly after the broadcast struck one of Trisolaris's three stars, and the explosion annihilated the planet.
- Book 3 · Ch 43Destruction of Trisolaris
A photoid struck a Trisolaran sun, a fire plume scoured the planet, and the star collapsed and exploded; humanity saw the light three days before.
- Book 3 · Ch 58Photoid alarm panic
A window avalanche reports Observation Unit #1 detected a photoid; unconfirmed officially, the public panics and flees to spaceports, causing chaos and crashes.
- Book 3 · Ch 59Explanation of photoid advance warning
The excerpt explains that although photoids travel near lightspeed, their radiation outpaces them, giving roughly 24 hours' warning when the photoid is about 180 AU away, so thirty-five observation units are planned.