The Terrans of Earth first detected the object that would come to be known as Ilium as anomalous output from an experimental solar system spanning network consisting of hundreds of space probes distributed throughout the inner and outer solar systems. It took the international effort of thousands of scientists, engineers, and support staff decades to build and launch the probes, slowly collect small, almost undetectable effects of gravity on smaller astronomical bodies such as asteroids or comets.

Back on Earth, they calibrated their gravitational data against all known solar objects. These include the big obvious things like the Sun, planets and their associated moons, comets, and asteroids. Any objects of significant were thought to be well catalogued by previous astronomical surveys. The process involved cross cataloging all known sources against the objects detected from the gravitational wave data. It is this process that led to the discovery of the Ilium Anomaly.

There are two major groups of asteroids that share the Jupiter’s orbit. They sit in special space parking spaces where the gravity of two large astronomical bodies cancels out. In this situation, the two major asteroid groups sit in the space where the Sun’s gravitational force cancels that of Jupiter in just the right way. The anomaly resided in one of these parking spots.

Preliminary results identified a previously uncatalogued object residing in at one of these parking spaces, also home to the Trojan Camp of asteroids. These results predicted a mass almost as massive as 624 Hektor; the largest and most massive asteroid in the camp. Despite how hard they looked, the scientists of Earth couldn’t find an object that massive anywhere on the electromagnetic spectrum. Nothing to see in the visible light spectrum. Nothing to see on radio, infrared, or x-ray.

Some scientists predicted it was evidence of a tiny black hole that traveled from the beginning of the universe only to somehow end up sharing Jupiter’s orbit with thousands of asteroids. This theory only holds up if the black hole showed up undetected somewhere in the last 10 to 20 years. Others theorize that this is evidence of an exotic form of matter that is invisible to the electromagnetic spectrum of light.

The mystery remained unsolved until historic first contact with the Ilian aliens of Ilium. But that is a story for another day.