Perpendicularity

A perpendicularity is a junction between the Physical, Cognitive, and Spiritual Realms. They are used by worldhoppers such as Hoid to go from planet to planet. They are formed through the concentration of Investiture. Because of this, they are most commonly found at places where a Shard's power is focused, often in the form of a pool of liquid. A Shard can control where their perpendicularity manifests. A perpendicularity may manifest as the Shards color.
== Creation ==
Perpendicularities occur naturally when a Shard spends a prolonged length of time Invested in a planet. Generally, leaving a planet would cause the Shard's perpendicularity to disappear. As a result, their presence is often used to indicate the presence of a Shard. Special circumstances, however, can prevent the perpendicularity from disappearing, and there is at least one Shard that fits these circumstances. Autonomy is capable of creating perpendicularities unexpectedly across multiple planets in a way that goes against the laws of Realmatic Theory as it is currently understood by arcanists. This requires specific conditions though. 
Perpendicularities can be created with Intent through various forms of Invested Art. 
It is more difficult to create a perpendicularity in the Spiritual Realm, than it is in the Cognitive or Physical Realms. However, it is not impossible to do so for some entities.
Some perpendicularities can be forcibly closed by having people utilize the massive amount of Investiture coming from it. Nightblood is able to collapse a perpendicularity.
== Mechanics ==
Perpendicularities are formed at locations with a large concentration of Investiture. The concentration of Investiture brings the three realms closer together and allows travel between them. Perpendicularities will not transport people between realms unless they travel through it with Intent. They can be used to see, and travel to, both the Cognitive and the Spiritual Realms. However, to transport oneself to the Spiritual Realm, one must push through it with their mind alone, lest they would travel to Shadesmar. 
The proximity of the realms around and in a perpendicularity also makes Soulcasting easier.
Aluminum can be used to take liquid from a perpendicularity, and it will stay Invested. Some perpendicularities are more Invested than others. The enormous concentration of Investiture in a perpendicularity makes it possible to become a Cognitive Shadow by entering one. In at least some circumstances, a perpendicularity's liquid Investiture may be unkeyed. Devices can be made to point towards a perpendicularity.
== Known Perpendicularities ==
; Scadrial
* Ruin: the pool below the Pits of Hathsin was Ruin's perpendicularity; it was the main path used by inter-world traders before it was destroyed by Kelsier.
* Preservation: Preservation's perpendicularity was the Well of Ascension. It served as Ruin's prison, making it extremely dangerous.
* Harmony: Harmony has a perpendicularity somewhere in the south, it is known to be under careful watch by the Malwish. An article in The House Record mentions a woman coming across a perfectly blue pool somewhere in the mountains in the Southern Roughs, and a sudden appearance of a strange figure by the pool. It's possible, though not confirmed, that this could be Harmony's perpendicularity.
* Autonomy: Autonomy briefly had a perpendicularity in Bilming, that was since destroyed by Marasi Colms, Armal, and several other Allomancers.
; Sel
* Devotion: The Pool near Elantris is Devotion's perpendicularity.
* Dominion: There is a second perpendicularity on Sel, presumably of Dominion.
; Threnody
* Threnody does not have a stable perpendicularity, but rather a number of unstable, unpredictable ones of a morbid origin. They may possibly have something to do with the creation of Shades, although the fact that the Shard of Ambition has died near the system has far greater influence on their creation. It is more of a circumstance than a location.
; First of the Sun
* First of the Sun is notable for having a perpendicularity, presumably Patji's Eye, without a Shard in residence. However, Patji is an avatar of Autonomy, which is likely the cause of the perpendicularity.
; Roshar
* Cultivation: Cultivation's Perpendicularity is located in the Horneater Peaks, under the surface of one of the Horneater Oceans. For worldhoppers of Roshar, it's the main method of travelling between Roshar and its subastral, Shadesmar. Most recently, it has been besieged by the Fused. It vanishes after she flees the planet.
* Honor: Honor's Perpendicularity is well-known among worldhoppers and spren to be unstable and dangerous. The exact pattern of its appearance is uncertain, although Bondsmiths are able to open it. The perpendicularity closes on its own within a few minutes.
* Odium and Retribution: Odium's, and later Retribution's, perpendicularity is the Well of Control. It is located underneath the Shattered Plains.
* The Surge of Transportation temporarily creates a miniature perpendicularity, allowing an Elsecaller or Willshaper to travel into Shadesmar from anywhere. However, returning back to the Physical Realm presents a far greater challenge, and can only be performed in some places. It is unclear if this allows travel to the Spiritual Realm.
* Knights Radiants: Whenever a Radiant swears an Ideal, they create a miniature perpendicularity allowing them to take in an influx of Investiture from the Spiritual Realm.
* Oathgates: Oathgates make use of perpendicularities in order to transport individuals between Realms and to different Oathgates across the planet.
;Nalthis
* Endowment: The location of Endowment's perpendicularity is unspecified. It is, however, located somewhere in the jungles of Hallandren. The Tears of Edgli owe their existence and their unusual properties as dye material to soaking up the Investiture flowing up from the perpendicularity. There are enough cosmere-aware people on Nalthis for there to be customs at this perpendicularity, and it is used for trade.
;Bjendal
* Unknown Shard: There is a perpendicularity on Bjendal. By , events on Bjendal made travel to the planet through the perpendicularity extremely dangerous.
;Yolen
* There is something similar to a perpendicularity on Yolen, despite the lack of a Shard.
;General Cosmere
* Autonomy: Autonomy has an ability to create and collapse perpendicularities in a way that goes against the understanding of Arcanists. These have specific constraints and conditions in order to be produced. Despite the specific conditions, she is known to have created perpendicularities across multiple worlds across the cosmere.
* Silverlight: Silverlight has a perpendicularity known as the Silverlight Nexus.
== Notes ==
Category:Perpendicularities
es:Perpendicularidad