The Ariadne Arm is a fictitious region of the Milky Way galaxy featured in the Subnautica series. Located on the outskirts of human-inhabited space, it was primarily settled by colonists from the former Mongolian Independent States. It is the location of Planet 4546B.
Location
According to narrative designer Seth Dickinson:
"The Ariadne Arm is a galactic structure at galactic longitude 053, in the direction of the constellation Aquila as seen from Earth, and north in galactic latitude towards the constellation Corona Borealis (Ariadne’s crown). It is a developed substructure of the Orion Arm, similar to the Radcliffe wave, and apparently characterized by close-packed stars. It lies coreward of Earth."
Background
According to a radio host heard in Voices from Beyond episode 1, the settling of the Ariadne Arm was viewed as "crazy" by Alterra, likely due to its remoteness. However, the colonization efforts proved fruitful, with Mongolian colonies in the area flourishing and Alterra taking a keen interest in the region.
The Ariadne Arm, specifically the 4546 system, yielded major discoveries for humanity, including the Architects and the Kharaa Bacterium, both discovered on Planet 4546B.
At some point, Kharaa began to spread rapidly throughout the Ariadne Arm. The method of its spread remains mysterious, with Zygimantis Tarvydas questioning whether Kharaa spread on the outside of space vessels or somehow managed to travel through space on its own. The outbreak caused many Mongolians to flee their homes as refugees, and the Ariadne Arm was eventually placed under martial law by Admiral Rathine Studaber of the Trans-System Federation.
