Trivia: When Kelvin gives Rheya the pill to relax, note that she takes a sip of water first and then puts the pill in her mouth. When director, Steven Soderbergh, asked Natascha McElhone if she did this as a part of her performance, as possibly a statement that if "you are created by Solaris that is how you take a pill?" Natascha was confused and informed him that was simply how she took pills. (00:48:25)
Trivia: The original 1961 story by Polish sci-fi writer Stanisław Lem was about the utter futility of attempted communications between humans and intelligent extraterrestrial species, because humans and aliens would have no common physical or psychological frame of reference for any attempted communication. For example, in the book, human scientists study the ocean planet Solaris for many decades without ever deciphering what they think are intelligent, changing patterns on the planet's fluid surface. They attempt to provoke a response from Solaris by firing X-rays at the planet, and the planet responds by reaching into the minds of the scientists and creating physical manifestations of their most guilty and painful memories. This has a traumatic effect on the baffled scientists, of course, and they have no idea what kind of communication they have established. Ultimately, the human scientists realise that the intelligence of Solaris is so vastly different from human intelligence, no meaningful interspecies communication is possible. This is a common theme in other works by Stanislaw Lem.