Part 4 — Chapter 1 | Sea of Tranquility • SparknotesAI

Part 4 — Chapter 1

The chapter begins with the narrator reflecting on the inevitability of the Earth coming to an actual end due to its star, the Sun, eventually dying.
The narrator recalls a catastrophic personal event, a year before he began his training at the Time Institute, involving his friend Ephrem, who had just returned from a vacation on Earth.
Ephrem shares a story about visiting an old cemetery with his daughter, where they discovered the grave of a young girl of the same age as his daughter. The discovery deeply unsettled Ephrem, prompting immediate exit from the cemetery. Despite Ephrem's usual fondness for graveyards, this instance was too impactful for him.
The narrator suggests that these personal losses feel like the end of the world, but the eventual end of Earth will result in literal annihilation.
To prevent the total loss of human history and achievement, colonies are being established on other celestial bodies, beginning with the Moon as a prototype for future, larger colonies in other solar systems.
The decision to establish colonies was announced in a press conference by the president of China, who emphasized the necessity of safeguarding human history from an eventual supernova or other astronomical event.
The narrator and his sister Zoey discuss the worthiness of the moon colony if the Sun dies, which Zoey explains as proof of concept and informs the narrator that far colonies have been populated for 180 years.