Solaris OceanAn ocean that imitates us

Could an exoplanet ocean show signs of life? This page covers transmission spectra, K2-18 b, dimethyl sulfide, biofilm electrical signals and Daisyworld.

K2-18 b, about 124 light-years away, is a planet orbiting a red dwarf, with a mass about 8.6 times Earth's. Whether it has an ocean, or life, is still being argued. The game's "Solaris Ocean" channel imagines it as a planet-wide ocean that only imitates and never responds, borrowing the premise of Stanisław Lem's 1961 novel Solaris.

This page covers the real parts: what was actually found at K2-18 b, how spectra reveal an atmosphere, the dimethyl sulfide dispute, the different models of ocean planets, and two real studies related to "planet-scale minds": biofilm electrical signals and Daisyworld. An ocean that is a mind is fiction.

K2-18 b: what is known and unknown

Discovery: K2-18 b was discovered in 2015 by the Kepler telescope, in the habitable zone of a red dwarf. Its radius is about 2.6 times Earth's and its mass about 8.6 times.
Transmission spectrum: when the planet passes in front of its star, a little starlight passes through its atmosphere, and different molecules absorb different colors. In 2023 the Webb telescope used this to identify methane and carbon dioxide in the atmosphere of K2-18 b.
Dimethyl sulfide: in April 2025 one team reported signs of dimethyl sulfide on K2-18 b, at a confidence of about 3σ. A joint analysis in July of the same year, combining more observations, gave only about 2.7σ, far from the 5σ required for confirmation. Other studies have pointed out that lifeless photochemistry can also produce it. On Earth dimethyl sulfide is made mainly by living things, which is why the hint drew attention, but follow-up analyses judged the evidence insufficient.
Ocean planets: some argue that K2-18 b is a "Hycean world", with a liquid water ocean covering the whole planet beneath a hydrogen atmosphere. Other models say it is more like a small Neptune with no ocean surface.

Can an ocean act as a whole

Biofilm electrical signals: a 2015 study found that bacterial biofilms use waves of potassium ions to pass signals across the whole colony, coordinating feeding like nerves.
Daisyworld: in 1983 Andrew Watson and James Lovelock designed a model planet with only black and white daisies. The two kinds rise and fall against each other, and manage to hold the planet's temperature within the range that suits them. Life can regulate its own planet.

These two studies only show that "a group can coordinate and life can regulate its environment". They do not mean that the ocean of a whole planet would have a mind.

Why Solaristics only gets messier

In the novel Lem invented a whole field of study devoted to this ocean, with libraries full of contradictory theories. Real science often looks like this too: the less evidence there is, the more explanations there are. The K2-18 b dispute is an example.

The idea in the game

What follows is game lore. The channel is discovered by unlocking "Webb telescope" in the Tree of Civilization and building a Dyson sphere in the interstellar-civilization era. In the scenario, what the Observer sees is an ocean covering a whole planet. It moves, as if thinking.

The mechanic is imitation: the ocean answers no language and only imitates. Every 20 minutes a "Mimoid" surfaces, with a shape taken from what the main civilization unlocked most recently. The more varied the main civilization's activity over the last hour (life, matter, cosmos, civilization and transcendence each count as one kind), the higher the output. Every attempt to talk to it fails.

In the scenario, scientists send a string of prime numbers at the sea, and the sea does not respond. Huge symmetric structures rise from the surface, and sink again a few hours later, never repeating. The channel has two endings: Unknowable and The Mirror. All of this is fiction.

Solaris (Stanisław Lem, 1961): the Gaia hypothesis and the ionic signals of biofilms are real research. A planet-wide ocean that is a single mind is fiction. In the novel, scientists study an ocean-covered planet that answers no language yet turns each person's deepest memories into physical beings.

The studies below concern exoplanets, oceans and ecosystems that do not depend on sunlight. They are related real science, not evidence of an ocean mind on K2-18 b.

A giant planet was found around 51 Pegasi, orbiting its star in 4 days, so the Solar System was no longer the only one. The discoverers won the 2019 Nobel Prize (Mayor and Queloz, Nature, 1995).
The Kepler telescope looks for new worlds by the faint dimming when a planet transits, and went on to find thousands (Borucki et al., Science, 2010).
Ecosystems that do not depend on sunlight exist around deep-sea hydrothermal vents, giving the origin of life a new candidate site (Corliss et al., Science, 1979).

Real basis

K2-18 b: K2-18 b was discovered by the Kepler telescope in 2015, in the habitable zone of a red dwarf. Its radius is about 2.6 times Earth’s and its mass about 8.6 times.
Transmission spectrum: When a planet passes in front of its star, a little of the starlight passes through its atmosphere, and different molecules absorb different colors. In 2023 the Webb telescope used this to identify methane and carbon dioxide in K2-18 b's atmosphere.
Dimethyl sulfide: In April 2025 a team reported seeing signs of dimethyl sulfide on K2-18 b at about 3σ confidence. In July that year a joint analysis combining more observations got only about 2.7σ, far from the 5σ required for confirmation; other studies also point out that lifeless photochemistry can produce it too.
Ocean planet: Some think K2-18 b is a “Hycean world”: under a hydrogen atmosphere lies a liquid-water ocean covering the whole planet. Other models say it is more like a mini-Neptune with no ocean surface.
Biofilm electrical signals: A 2015 study found that bacterial biofilms use waves of potassium ions to signal across the whole colony, coordinating feeding like nerves.
Daisyworld: In 1983 Watson and Lovelock designed a model planet with only black and white daisies: the two kinds rise and fall against each other and can hold the planet's temperature in a range that suits them. Life can regulate its own planet.
Solaristics: In his 1961 novel, Lem invented an entire discipline devoted to studying this ocean, with libraries full of contradictory theories. Real science often looks like this: the less evidence, the more explanations.
Solaris (Stanisław Lem, 1961), the science: the Gaia hypothesis and the ionic signaling of bacterial biofilms are real research; an entire planet’s ocean being one mind is fiction.

Related research

These studies relate to this topic but are not direct proof of this page.

The first exoplanet: A giant planet was found around 51 Pegasi, circling its star in 4 days. The solar system was no longer unique. Nobel Prize 2019.
Source: Mayor & Queloz, Nature 1995, "A Jupiter-mass companion to a solar-type star"
Kepler: The Kepler telescope stared at one patch of sky and looked for new worlds by the faint dimming when planets transit, eventually finding thousands.
Source: Borucki et al., Science 2010, "Kepler planet-detection mission: introduction and first results"
Deep-sea hot springs: Ecosystems that do not depend on sunlight exist around deep-sea hot springs, giving the origin of life a new candidate site.
Source: Corliss et al., Science 1979, "Submarine thermal springs on the Galápagos Rift"

Game lore (fictional)

Node “Ocean planet”: What the Observer sees is a sea.
Node “Mimoid”: A structure rises from the sea, shaped like something the main civilization did recently.
Node “First conversation”: The scientists beam a string of prime numbers at the sea. The sea does not respond.
Node “Symmetriad”: A huge symmetrical structure rises from the sea and sinks again a few hours later, never repeating.
Node “Second conversation”: A scientist encodes his own EEG into rays and fires them at the sea. The next morning, a person long dead is sitting at the end of the corridor in the research station.
Node “Visitors”: The visitors will not say what the sea is thinking. They are only the deepest part of your own memory.
Node “By the sea”: You sat by the sea for a long time.
Channel ending “Unknowable”: Generation after generation of scientists came to the shore and left with new theories. No one knows what it is thinking.
Channel ending “The Mirror”: You stop asking it to speak and just watch. Again and again the sea brings up things you have done, like a very slow mirror. What you see in it has always been yourself.
Summary of the novel Solaris: Scientists study a planet covered by an ocean that may be one enormous mind. It answers no language, but turns the deepest memory in each person’s heart into a physical being.

See it in the game