The most surprising thing we learned about physics once we developed interstellar travel was that it was all wrong. In particular, the assumption that spacetime is homogenous, which we had taken as an axiom, was proven to be utterly and horrifically false. The homogeneity of spacetime essentially says that the rules of physics are the same throughout the universe. No matter where you go, an object in motion tends to stay in motion, every action has an equal and opposite reaction, etc. You know, The Works. We figured that, just because these laws were true everywhere we went, they must be true everywhere. But we have since discovered that this is no less naive than expecting the laws of the US to protect you in North Korea. And nowhere is the inhomogeneity of spacetime more apparent than in the inter-filamental voids, the International Waters of the universe.
A particularly well-known example of how little our rules mean outside our local neighborhood is the planet Nyx, more commonly called “The Shadow Planet”. The star that it orbits, Erebus, is quite unlike anything that can be explained by conventional physics. Rather than emitting light, it exudes darkness, cloaking the planet in night. However, just as light can be absorbed by an opaque object, so too can this darkness. Nyx is illuminated only by shadows, swaths of radiance which cut through the gloom like sunshine. As Einstein famously (didn’t) say, “Darkness is just the absence of light.” On planet Nyx, the reverse is true. The invisible landscape is dotted with lights of unnervingly familiar shapes. Brilliant shadows, too similar to the human form to be chalked up to coincidence, flit across the surface. Yet we cannot know with any certainty whether or not humanoid beings inhabit Nyx, as the shadows never intersect. Without the illumination of other shadows, they remain cloaked in darkness from cradle to grave. Perhaps this is merely an unusual custom of theirs, but one cannot discard the possibility that they know they are being watched.