Slidespace

Slidespace is a unidirectional spatial distortion phenomenon that forms a figure-8 loop around the core of the Milky Way galaxy. A cross-section of slidespace takes the shape of an ellipse large enough to swallow a small planet. Matter that enters slidespace will be dragged along its path at unfathomable speeds until it manages to exit the anomaly. At these speeds an object within slidespace is able to travel from one end of the galaxy to the other in a matter of hours. The speed comes from the anomaly itself and not the inertia of the traveling object, so ships carrying life are able to make use of slidespace as a highway without enduring absurd G-force. Unusually, traveling at such speeds appears to have less of a temporal displacement effect than current models of physics would demand.
Science has come far in its ability to understand the effects of slidespace. The speed, path, and observed internal properties are things heavily documented and studied by physicists of all species. Developments using this data has led to the civilizations local to slidespace traveling along it's route with relative confidence. By making use of powerful slidestations and satellites deployed within the anomaly, ships are able to chart courses that carry them safely through slidespace to distant systems. Slide-travel has only gotten easier and more commonplace, but much of its route is unexplored due to the immense distances and specific exit timings involved. The Slidescouts exist as an organization in the service of charting these unknown reaches.
When it comes to how slidespace came to exist, what causes it, or where it comes from, very little is known for certain. The difficulty in answering these questions has led to some regarding the anomaly as some sort of god-given gift or sacred place. The leading hypothesis is that slidespace is formed as a byproduct of the supermassive black hole at the center of the galaxy via mechanics unknown to science.