Kelvin, Rheya, and the ocean's visitors
The psychologist Kris Kelvin arrives at the Solaris station and is soon visited by Rheya, his wife, who had killed herself years earlier after he left her. She is a physical copy built from his memories, made of neutrinos, and she comes back after every attempt to destroy her. Kelvin sends the first copy away in a rocket. The second copy becomes aware of what she is and chooses to be annihilated. The ocean gives no sign of why it made her, so the most intimate event in the book is also the least explained.
