Solaris (2002) and the Goldberg Variations
The 26th piece from Bach's Goldberg Variations, Variation 25 “The Black Pearl”, is heard by Snow in his chambers as he advises Kelvin to lock his door at night.
How much sleep do you need, Kelvin?
How long do you think you can go without sleep?
Of course, Kelvin doesn't yet know what's about to happen to him in his sleep. He hasn't yet been visited by Rheya.
Well, when you do go to sleep, I find I sleep much better with the door locked.
Having Snow listen to Bach in his room gives him an attribute of being human, of missing home, of being connected to a time before being on the spaceship.
Listen to Variation 25, “The Black Pearl”, from Bach's Goldberg Variations, in the video below, played on the piano.