After Deleting the Moon, My AI Doesn't Work

In my story, the sudden deorbiting of the moon was just the beginning. Subsequently, the planets in the entire solar system collectively moved outward, and the earth became frozen and dead. The source of all this is a passing giant gravitational source, which detonated the collision between the Milky Way and the Andromeda Galaxy in advance. Human beings are forced to embark on an interstellar wandering road. But in deep space, what we encounter is far more than a cruel environment. When science fiction comes into reality, what do you think will be the real enemy of mankind in the universe? Are they alien life forms that are incomprehensible and weird? (Insect swarm, silicon-based civilization, energy body...) Is it the physical rules themselves? (The constants in different star fields are different, and our technology may fail...) Is it the loneliness of civilization and the alienation of human nature brought about by time and distance? (During the century-long voyage, will the spaceship society itself collapse?) Or... We finally discovered that the disaster itself was a "cleaning" of the "experimental site" by some higher being? In my book "AI Code: Humans Do Not Make Sacrifice to Civilization", the protagonist, as the earliest insight into the disaster, will lead the survivors to face all the above challenges. But the final answer may be colder and more shocking than all these imaginations.