[Fred Brackin]

40 years ago, when I was in college (and doesn't that phrase cut like a knife?) My first campaign for FGU's Space Opera had a reverse-Dyson sphere.

It was a sphere the size of Earth's orbit but the Precursors lived on the outside so when the machinery failed they didn't all fall into the center of it. Making big streetlights on the outside were a lot simpler.

It was also built around a larger than Sol-szed black hole rather than a star. It was probably used for multiple sorts of Precursor-like exotic technologies.

It had been mostly wrecked in the last Precursor war but enough of the defense system still worked that ships over 273 tons one at a time were shot at with what were very big guns by modern standards. Very difficult to move in and take over for any government.