Singing Deep

[WARNING] EXPOSURE TO THE SIGNAL REFERRED TO AS "SONG" EMITTING FROM THIS DIMENSION IS A WELL DOCUMENTED COGNITO-HAZARD [WARNING]
The Singing Deep is a dimension parallel to our own with strange properties unique to it. It is likened to a liquid ocean, although there is no physical surface beyond where it exits into real space and some unique situations. It seems to be completely suffused by a material referred to as tehoma. This "liquid" is mildly toxic, dense, contains no known real space elements, and is generally inhospitable to humanity. The discovery of The Singing Deep is poorly recorded and is pre-coalition but most records indicate that it was discovered through a series of experiments on recording devices which gave odd readings in the presence of particular complex layered audio frequencies.

Anything that spends extended periods of time within tehoma undergoes a process called "pearling" whereby tehomite, the solidified form of tehoma, gathers like a patina on the outside of the object. Another notable feature of the Singing Deep is its denizens, known as "Notes" and "Chords". These creatures resemble some old Earth invertebrates, such as nudibranch colonies, or widely old Earth Medusozoa or "Jelly Fish". These creatures are mostly docile, though have been known to be hostile and grow to incredible sizes. They also produce a sound that is considered by some to be the "song" of the deep. This song is a haunting layered noise similar to old Earth whale song and shifting glacial plates. Although the denizens of the Singing Deep do produce the sound, the song is also apparent without their immediate presence. Additionally, the song can be heard through interactions with tehoma in real space. Tehoma is also the first "emotionally resonant" material discovered by humanity, a quality that allows it to "conduct" emotional brainwaves through some as yet unknown mechanism. The Singing Deep has been a scientific mystery for millennia, and research is still ongoing.

The most materially relevant quality of the Singing Deep is the compression of spacetime within its waters. Due to this, any distance travelled through the deep translates into considerably more distance in real space. A day of steady travel in a Songship can often result in 5 real space Light Years being covered, roughly translating to an equivalent real space speed of 1.97e+12Km/hr - though it is more like travelling underwater than in a frictionless vacuum. It is for this reason that the Singing Deep is central to nearly all modern technological advances, and all long distance interstellar travel. In the approximately 1000 years since the discovery of the Singing Deep, it has also become culturally central to several peoples within the Pearlescent Expanse, such as the Universal Choir.

Tehoma
Tehoma is a translucent dark fluid, it is more dense than water and exerts gentle force on things displacing it. It has become vital to hundreds if not thousands of technological advancements made over the past millennia, due to its strange physical properties. Tehoma has several forms, it exists naturally as a liquid, but will solidify into a substance known as "Tehomite". This begins as a thin layer, producing a dramatic iridescence similar to an oily sheen or black mother of pearl. Over time this "pearling" as its known can grow dramatically, although the process will slow over time. Dramatic examples of this can be seen on Fugue but it is also common on all objects that spend any length of time in the Singing Deep or Tehoma. Tehoma can also generate energy though it must be converted to "Energized Tehoma" a process that involves playing a complex and layered series of harmonic tones. Crystallized Tehoma can also be derived from its energized form, and is a significantly more stable form of the energized state. All forms of Tehoma are also the first "Emotionally Resonant" substances discovered by humanity, acting as amplifiers and conductive to emotional brainwave activity, producing intense insular dream like states for those exposed by themselves, or bridging consciousnesses when two are immersed and within proximity of one another.

Resonant Tones and their effect on The Singing Deep
The Singing Deep is only accessible via several combinations of complex layered series of audio tones, commonly known as Resonant Tones. When these are played, or even sung, one can quite literally rend reality, opening a dimensional bridge to The Deep. When done without any protective measures this can be quite dangerous, as it can draw Singing Deep lifeforms through the rift, and although it can close on its own, these rifts will sometimes grow and stabilize, and a different set of tone combinations is required to seal these dimensional bridges. Beyond simply offering access to this dimension, audio signals have dramatic effects on the lifeforms known as "Chords" and "Notes", which have been extensively recorded "singing" along with machines or individuals who are producing Resonant Tones, this has been observed temporarily changing the biologic processes of the lifeforms themselves and any living creature harmonizing, this process is deeply important to Chorism and Psalm technologies. Tehoma itself will also produce noise and go through a state change if presented with the correct Resonant Tones, this is central to the production of Energized Tehoma. All Resonant Tones are related, mathematically to a cognitively hazardous Signal emitting from the deep known as the "Song" Signal.

The "Song" Signal
Discovered in the late 5th Century by a 7th Mantra Foundation Head Researcher Dr. Illumin Randhawa and their team. The signal was a "blank spot" that was implied to exist at the center of all known Resonant Tones and Foundation had been in pursuit of it for well over a century. Upon discovery it was revealed to be a distinct signal emitting from the deep, but with seemingly endless interior complexity upon any further investigation, although the "Song" Signal can be replicated, no complete replication appears to be possible until a equation or set of equations explaining its fractal nature are discovered.

The discovery of the Signal and its resulting effect on those present fulfilled several other established 7th Mantra hypotheses, which is that the Signal itself was the first recorded Cognitive Hazard. The Song Signal can, when a being with complex cognitive function is exposed, direct their cognition towards particular concepts related to the Singing Deep, and this "direction" will persist indefinitely, regardless of further exposure to the Song Signal. Similar to the results derived from the ancient Toxoplasma gondii parasite of earth, the Song Signal will lead to more positive reactions to Singing Deep Lifeforms in some 89% of those infected. The subjects interest will be drawn to the very concept of "The Singing Deep"; subjects report a significant increase in errant thought, day dreams, sleeping dreams, related to the Singing Deep. It is also seen that indulging these thoughts, pursuing one's new found interest in the Singing Deep, releases very subtle amounts of Serotonin, Dopamine, and Oxytocin. This interest also did not need to be indulged in any way that relates to material reality, philosophical, spiritual, and many diverse methods of "pursuit" of this interest all led to nearly identical biological effects on the brain of the subject.

Implications of the "Song" Cognito-Hazard
The most pressing implication of the "Song" Signal, and its nature as a cognitive hazard, is what it implies about the very nature of the singing deep itself. All things within the Singing Deep are effected by the Song, it causes tehoma to produce resonate sound signals and can change the very state of the extradimensional matter. There are many different hypotheses of what this could potentially mean, that the Deep itself was somehow created by some other extradimensional force or beings. However most prominent is that there is some sort of neo-consciousness to the deep itself, something reaching out to beings, such as we.

Melody Gates
Melody Gates are an ancient technology, being roughly as old as the Coalition itself. Melody Gates are humanity's safest method for entering or exiting The Singing Deep. These structures have a very large range of sizes, small humanoid sized gates or smaller are used in research, and exploration. While colossal kilometre wide gates can allow entire fleets of spacecraft into The Deep as well, for miraculously quick travel across real space. Melody Gates are generally composed of one primary ring, containing the equipment and instruments required to produce Resonant Tones, and in larger Melody Gates, there is often a crewed control room. The rest of the structure are nodes that create a sphere. This ring and the connected nodes open a gate to The Singing Deep while keeping it completely contained. Ships or objects enter into the sphere, and it as the gate begins to work it will slowly "fill" with tehoma. This tehoma is then energized via further resonant tones until it begins to exist in both real space, and the Deep, the signal is then released from the real space side. The Energized Tehoma vanishes dramatically. This is a process that is eerily noisy regardless of if there is atmosphere to conduct said noise. The haunting drone of the Deep rises to a piercing crescendo before vanishing completely, this is sometimes referred to as "The Scream" or "The Shout" or "The Echo"