Old sci-fi story about Alien planet with psychic ocean

Question

Back in the day I had to read a story from the "recommended" books section and I chose this.

The story is about a guy (let's call him Steve) having to visit a planet that already has a human base set up, but I think they lost contact with the inhabitants, which prompted the reason for Steve to be sent off there. He had some kind of experience that was useful for the mission. As I remember, Steve wasn't that keen on the idea because the planet was pretty far, so it would take years to reach it.

When Steve reached the planet, it turned out that most of the inhabitants were gone sans for one guy he finds later at the base.

The planet had a vast ocean that, the longer Steve was on this planet, the more he felt like it could talk to it. Something along the lines of the ocean being a sentient being.

After being on the planet for a while, Steve suddenly finds his girlfriend there, which should be impossible. Pretty sure he found her naked, and by close inspection it turned out that she had smooth soles "smooth as a child's that has never walked before", implying it's a clone planted by the sentient ocean for X reason. He later develops feelings for this girl (since she looks like his girlfriend/wife). I also think that the original girl is dead, or they broke up, some tragic background story. The girl was worried that Steve likes her because she looks like his previous partner, but Steve assures her that while they look the same, she acts different.

Steve got a cell sample from the girl, and upon closer inspection under the microscope it turned out that the cells are made up of something smaller than an atom, so small that their equipment couldn't focus enough to actually see the thing the cell is made of.

I never finished the story, so I don't know what happens in the end, but that's all the info I remember.

Answer 1

I believe this is probably Solaris (1961, English translation 1970) by Stanislaw Lem.

Kris Kelvin is sent from Earth to Solaris, where there is a research stations studying the gel-like organism that inhabits the world-spanning ocean. He meets Snow, now in charge, and finds Gibarian, the former head, has killed himself. The only other live human on the station is Sartorius.

Nevertheless, he meets Rheya, a former lover of his who killed herself on Earth, and observes the appearance of other seeming people who could not actually be there. (These are simulcra constructed by the sentient organism in the ocean for unknown reasons.)

The bit about the soles of her feet is fairly distinctive; first when he finds Gibarian's visitor:

I looked again at the soles of her naked feet; they had not been flattened or deformed in any way by the weight which they had had to carry. Walking had not calloused the skin, which was as unblemished as that of her shoulders.

And again when he meets the simulcrum of Rheya:

Leaning forward, I took hold of one of her ankles and ran my fingers over the sole of her foot.

The skin was soft, like that of a newborn child.

I knew then that it was not Rheya, and I was almost certain that she herself did not know it.

The cells of the simulcra are composed of neutrinos, so smaller than can be resolved.

"The atom is the ultimate constituent element of our bodies. My guess is that the Phi-beings are constituted of units smaller than ordinary atoms, much smaller."

"Mesons," put in Sartorius. He did not sound in the least surprised.

"No, not mesons... I would have seen them. The power of this instrument here is between a 10th to a 20th of an angstrom, isn't it? But nothing is visible, nothing whatsoever. So it can't be mesons. More likely neutrinos."