Solaris.
The name “Solaris” invokes the name of the sun that is the source of life-giving warmth to Earth. As such, it can also be seen as a pun on “son,” since much of the novel’s action is psychological in nature, dealing as it does with human sexual drives and erotic guilt, albeit in complex, symbolic ways. Thus, the planet Solaris can be seen as a place where humanity is forced to confront the dark side of its own psychology.
Solarian ocean. Body of water that covers the entire surface of Solaris. This mysterious body of colloidal fluid is both a geographical feature and a major character of the novel. It is apparently intelligent at some level, and is believed by some humans to cause the peculiar perturbations in the planet’s orbit, rather like an extreme version of the “Gaia hypothesis,” which suggests that the totality of life on Earth works together to preserve conditions suitable for life to continue.
This living ocean is also the probable source of the mysterious Phi-creatures, beings that resemble their human counterparts so closely that only microscopic examination can distinguish them. The Phi-creatures appear to be intermediaries, an attempt by the ocean to create an interface through which it can communicate with the humans that have come to its planet. However, there is no known communication channel between the Phi-creatures and the ocean, so these attempts at communication ultimately prove fruitless.
Prometheus. Spaceship on which protagonist Kris Kelvin arrives on Solaris. While most American science fiction writers of the 1960’s would have lavished upon readers detailed descriptions of the physical hardware of their spaceships, Lem keeps the technological details spare, a minimum necessary to create the impression of an interstellar vessel. As in the rest of the novel, the thrust is primarily philosophical, and the classical reference of the ship’s name is significant. In Greek mythology, the Titan Prometheus was renowned for stealing fire from the gods and giving it to humans, who had been denied such natural defenses as sharp teeth and claws. However, that act led to Prometheus’s being chained to a rock, where his liver was gnawed by a vulture as punishment. Thus Prometheus was an ambivalent figure, symbolizing both enlightenment and condemnation, civilization and punishment. Similarly, the spaceship Prometheus is both a technological triumph and the instrument by which Kelvin is delivered to psychological torment.
Research station. Human research base on Solaris that floats at an altitude of from five yards to nearly a mile above the ocean. It is maintained by gravitors, a kind of gravity-control device. The station can be thrust well into the planet’s stratosphere at the first hint of upheavals in the planetary ocean, such as one that took the lives of 106 people some years earlier.
The station is a bit of earthly environment brought to this alien world, within which the human researchers live. As such it can be seen as a sort of womb, even a mother figure. At the same time, it is also symbolic of the idea that the explorers come to a distant world thinking that they are trying to learn about an alien world, when in fact they are attempting to impose upon it earthly certainties and expectations.