The Interloper
The Interloper is a cold brown dwarf, a failed star of about 50 Jupiter masses. It formed in the same birth cluster as the Sun, 4.6 billion years ago, and drifted away across the galaxy. In 2041 an infrared survey found it coming back.
Formally it is catalogued as DSO-1. Most people call it the Interloper, and Hollowers born since the Conjunction call it the Ember, for the dull red point it makes in the sky. Children are taught it will come back.
What a brown dwarf means
- It is faint. It glows mainly in infrared, which is why it was found late, and why the warning was decades rather than millennia.
- Its moons can be warm without a bright sun. They are heated from inside by tides.
- It is light enough to be captured. It wrecked the inner system on its way through, lost energy flinging bodies outward, and stayed bound to the Sun.
Its moons
The Interloper had a family of icy moons with oceans under their crusts. Without a bright sun, they were kept warm from inside by tides, the way Jupiter keeps Europa's ocean liquid.
Spoiler: what lived there
The largest moon, which humans will come to call Hearth, held a complex biosphere. Orbital resonances between the moons made its tidal heating rise and fall over long cycles, giving Hearth warm epochs and frozen ones lasting centuries.
Life there evolved to wake, flourish and then go dormant in step with those cycles. Every cold epoch killed anything that could not wait.
The Passage and the capture
In 2094 the Interloper passed about 1.5 AU from the Sun, between the orbits of Earth and Mars. Earth was thrown onto an eccentric orbit, and Mars onto one that crossed Earth's.
Tides and close passes stripped and shattered several of the Interloper's own moons. Their ice and rock was thrown across the outer belt and into high-inclination orbits where the old belt colonies rarely go. Flinging that material away cost the Interloper energy, and that is what let the Sun capture it.
Spoiler: what it threw away
Among the moons it shattered was part of Hearth. The Interloper stayed by throwing away its own moons, including the aliens' home. Hearth was, quite literally, its reaction mass.
Timeline
Hollowers count years from the Conjunction. The game begins in 2251, or 150 AC: six generations on, well documented, endlessly retold, and already turning into myth.
- 2030s–50s
The Climb
Fabs in low Earth orbit make goods that can only be made in orbit. Shackleton Base on the Moon builds mass drivers. Prospectors survey the belt.
- 2039
Arsia Station
The first permanent base on Mars: a few hundred people at first, around 20,000 by 2094.
- 2041
Discovery
An infrared survey spots a faint, fast-moving object and catalogues it as DSO-1.
- 2044
The Forecast
Its trajectory is confirmed: it will pass through the inner system in about 50 years. Denial, panic and doomsday cults follow.
- 2045–94
The Exodus
Fifty years building habitats inside belt rock: Ceres, Vesta, Hygiea and hundreds of smaller bodies. There is never enough room.
- 2061
The Berth Acts
Berths are split three ways: by skills, by public lottery, and by sale through the Charter Companies to fund construction.
- 2088
The Last Launch
Shackleton's mass drivers fire their final loads to the belt. The crews stay behind. Hollowers still call them the first reaction mass.
- 2094
The Passage
The Interloper passes 1.5 AU from the Sun. Earth is thrown onto an eccentric orbit, and Mars onto one that crosses Earth's.
- 2094–2101
The Long Fall
Earth swings between scorching and freezing. Arsia Station is evacuated to the belt. Billions die waiting.
- 21010 AC
The Conjunction
Mars strikes Earth. Both worlds are melted, and a vast debris field spreads along the old orbits.
- 0–20 AC
The Lean Years
Debris storms and habitat failures. About 400,000 people reached the belt; around 100,000 are alive at the end.
- 20–60 AC
The Holding
The survivors consolidate. The Ceres Assembly forms, Shackleton Port rebuilds the Solar Web, and the Charter Companies collect on Exodus debts.
- 60–100 AC
The Daughter Cities
Crowded colonies send out splinter groups to found new ones, as Greek cities once did. The belt fills with city-states.
- c. 90 AC
The Web Charter
Dozens of ports sign up to Shackleton Port's trade law, forming the Shackleton League. The Red Clans hold their first Moot.
- 95–115 AC
The Company Wars
Eleven Charter Companies fight, merge and collapse into four.
- 125–140 AC
The Claim Wars
The great blocs fight over the last unclaimed rock in the old belt.
- 140 AC
The Hygiea Settlement
The peace that ends the Claim Wars opens frontier charters as a pressure valve.
- 140–150 AC
The Frontier Opens
Charters are granted for the outer belt and high-inclination orbits, where the Interloper's debris lies. Prospectors report a strange "rot" in some rocks. Nobody pays much attention.
- 2251150 AC
The game begins
A splinter faction leaves its home colony on a single colony ship, bound for the frontier.
- c. 2325c. 224 AC
The Return
The Interloper's next closest approach.
The Return
The Interloper now circles the Sun on a long, eccentric orbit of roughly 230 years. Its next closest approach falls around 2325, about 75 years after the game begins.
Forecasts disagree on how close it will come. The optimistic models keep it beyond Jupiter, which would still stir the belt into debris storms and comet showers. The pessimistic ones bring it through the belt itself. In the belt, which forecast you believe is a political position.