A random idea inspired by minor story elements in the anime movie Odyssey of the Celestial Ark, and by the TNG Episode, The Chase (don’t ask me, I haven’t watched TNG yet because I can’t). Already showed my idea on the Discord Server, might as well expand on it further here.
A wormhole appears in a Lagrange point 40 AU away from Schatten V. Which leads to a chaotic Binary Black Hole System.
The System is a Binary Black Hole System with 8 planets. The Black Holes are in a stable (i.e not falling into each other, but not flying away from each other either), but rapid, orbit around each other, due to their close proximity to each other, they generate powerful Gravitational Waves.
The System is located in a supermassive galaxy, in an area of the Universe 40 lightyears away from the edge of the Observable Universe. (Whether or not this will be relevant is up to you guys)
Of the 8 planets, 3 are inside the Ergosphere of the Black Holes, the first planet is in a constant orbit 3-6 AU away from the Event Horizons of both black holes. As such, time is heavily dilated in the planet, with 40 Earth years passing every 10 minutes if one was on the surface of the planet.
The second planet is in a highly elliptical orbit that takes it out of the Ergosphere at its apoapsis, happens every 4 Earth Years, and lasts for about 3 to 4 Earth Months before it enters the Ergosphere again. As such, time dilation isn’t as severe, on average, 6 months would pass on the Earth every 1 hour on the planet. Worst is at its periapsis, where every hour is 10 years on Earth.
The third planet is straddling the border between the Ergosphere and Normal Space and is tidally locked to the center of the system. Which results in a relatively insignificant time dilation, 5 hours pass on Earth for every hour spent inside the half of the planet inside the Ergosphere.
The fourth planet is where all the good stuff is. The planet is about the same general size and mass as the Earth, albeit a tiny bit more massive, and also supports life. The planet is unique in that plant life there is old, around 9.7 Billion Years old. The planet has 4 major continents, and each of them have several thousand abandoned cities. Some Technology can still be salvaged, whatever they may be is up to you guys.
The fifth planet is a gas giant, about 4x more massive than Jupiter, it has a giant ring consisting of 78 individual rings that stretch all the way to 1 AU of the fourth planet, and about 2 AU from the sixth. Defunct stations litter the orbit of the gas giant, a total of 53 defunct stations, 8 of which are in rapidly decaying orbits.
The sixth planet is a Giant Solid Planet with a mass of 27 Earth Masses. The planet is mostly made out of ice, but a massive network of underground tunnels stretch the entirety of the planets’ icy crust. Leading to similarly abandoned cities. The weird aspect about the planet is the internals: the planet is hollow, the center of the planet is a reactor/power source of unknown type.
The seventh planet a new planet, around 7 million years old. As massive as Schatten IV, and is volcanically active, so much so that a spectacular sight can occasionally be seen: a whole section of the planet the size of Eurasia forms a bulge that reaches into space, before subsequently collapsing in on itself.
The eigth and final planet is…more or less a mystery. It’s a silvery-green planet that’s as large as the Earth. The planet is more artificial than natural, made up with a giant network of metal. Surrounding it is a giant structure far far larger than the planet itself. (Reference pic below)
Beyond it is a massive but unfortunately inactive Subspace Gate.
(Reference image below)