The Quantum Moon is a planetary object in a state of constant quantum superposition. It exists in orbit around six different large astral bodies at once until it is observed by a conscious observer.
The Quantum Moon is an enigmatic natural satellite that exhibits macroscopic quantum properties, appearing in many different locations in the Solar System, and disappearing when unobserved. The Moon itself is covered in a thick grey cloud layer, obscuring its surface completely.
The Moon randomly phases between six positions in the Solar System when not being observed. It can exist in orbit around the Hourglass Twins, Timber Hearth, Brittle Hollow, Giant's Deep, the outside of Dark Bramble, and a Sixth Location is alluded to by in-game text.
The Moon itself emits a signal on the Quantum Fluctuations frequency and can be detected on the Signalscope. Numerous Quantum Moon Locators built by the Nomai exist throughout the system, capable of pinpointing the location of the Quantum Moon (except for the Sixth Location), such as on the South Pole of Ember Twin and the Tower of Quantum Knowledge.
Attempting to land on the moon conventionally will cause the player to pass through it entirely, mysteriously emerging from the cloud layer back into space, the Moon itself likely having disappeared already.
Five Shards broken from the Quantum Moon can be found scattered throughout the Solar System. The Shards, as well as several Nomai structures dedicated to Quantum Moon research and pilgrimages, teach different rules of quantum behaviour which prove key to reaching the Moon itself, and eventually the Moon's Sixth Location.
At the Tower of Quantum Trials on Giant's Deep, the rule of Quantum Imaging is taught. To properly land on the Quantum Moon, a photo of the Moon must be taken before entering the atmosphere, and observed during landing, preventing the Moon from disappearing and allowing landing on its surface. The player will always land at the Moon's south pole, regardless of the original entry vector.
The Quantum Moon's surface is unique in that it will look different depending on the planet it orbits, resembling and gaining its features (therefore having six possible variations). All objects on the Moon's surface will also display quantum properties, moving when unobserved.
Among the general landmarks (in the first five locations) are a dead Nomai corpse belonging to Solanum, and her Nomai Shuttle (unless recalled by Brittle Hollow's Gravity Cannon). However, most important is the Quantum Shrine, a quantum structure built by the Nomai that allows users to force the Moon to move between its six locations.
The Quantum Shrine, like the other surface objects, moves and changes locations on the Moon when unobserved. The Shrine operates on the rule of Quantum Entanglement, taught by the Cave Shard on Ember Twin. To use the Shrine, one must enter and shut the door, with a lantern inside that can be turned on and off. When in complete darkness, the rule of Quantum Entanglement allows the Moon to move between its six locations (and thus changing its surface), with its current location indicated by the locator built into the Shrine's wall.
The Quantum Shrine can be used to reach the Moon's Sixth Location. At the Tower of Quantum Knowledge on Brittle Hollow, it is taught that to reach the Moon's Sixth Location, the Quantum Shrine must be used while on the Moon's North Pole. Attempting to reach the Sixth Location while the Shrine is at any other location on the Moon will result in the Shrine's door being completely blocked by obsidian stone identical to the Quantum Shards, unable to be exited.
However, the Moon's North Pole is often blocked by different terrain features in the Moon's five other locations, requiring a process that involves using the Shrine multiple times at different positions, in different Moon locations, to reach a path where the North Pole can be accessed (This can most easily be done by entering the Shrine near the North Pole on the Dark Bramble variant, transferring to the Timber Hearth variant, and approaching the North Pole from there.). Once at the North Pole, the Shrine can appear and be used there to properly reach the Sixth Location.
The Sixth variation of the Quantum Moon is highly enigmatic, and vastly different from the other five variants. The surface is mainly smooth ground covered in purple strata, with many outcroppings of strange, crater-marked obsidian stone in odd geometries, identical in composition to the Quantum Shards. An open pathway leads from the Shrine across the Moon's surface all the way to the South Pole, where a still-living Solanum can be found and conversed with, standing under a large vortex in the Moon's cloud layer that leads into deep space.
Attempting to exit the Moon's atmosphere through the vortex will immediately return the player to the Moon's Timber Hearth location and variant.
Texts and recordings
SOLANUM: I am here! After watching it wander the skies for so long, I am about to stand (for the first time) on the Quantum Moon.
SOLANUM: As expected, my shuttle has landed at the moon’s south pole. I will make the remainder of my journey on foot.
SOLANUM: We don’t know why the Quantum Moon always welcomes its visitors at the south pole, just that this is true.
SOLANUM: As a child, I considered such unknowns sinister. Now, though, I understand they bear no ill will. The universe is, and we are.
SOLANUM: I am ready.
You have recalled the rule of quantum imaging.
Recall the rule of quantum entanglement.
Recall the rule of the sixth location.
Notes & Trivia
- It is possible to remove the fog effects while on the moon by boosting into the cloud layer and back down again, at least on the Hourglass Twins variant
- The Quantum Moon is in fact the Moon of the Sixth Location, but due to the nature of said location, the Quantum Moon shares the quantum effects of it, which is why it can be seen orbiting each of the five main planets of the solar system.
- It is impossible to use the Moon at the Sixth Location to reach the Eye of the Universe early. Attempting to do so will either fail due to the atmosphere blocking your progress, or you will go through the vortex back to the Timber Hearth variation of the Quantum Moon.