Stellar spheres

It was nice to recall the story of Saint Khafkan foiling the Sealer's plot. I picked up a book about this bit of history, because I could not shake the idea that in Jove society, their version of the Sealers may have been more successful. Perhaps not with an attack, but by gaining political power.

What happens next? A very advanced civilization will ultimately control all matter in its (sealed-off) star system, and futurists have theorized that they would reorganize this matter into a giant spherical shell surrounding their home star, to capture all the star's energy and let none of it escape into the dark depths of space.

If we add up all the mass of the planets circling our star, from Mikew to Derdainys, and redistribute it evenly on a shell of 1 AU - twice the distance between Amarr Prime and our star, we have about 7 tonnes of material to work with per square kilometer of shell. Enough to build a shell sturdy and thick enough for people to live in.

However, such a sphere would be inherently in danger of colliding with its central star. If the star is not completely at rest with respect to the sphere, it would just keep on cruising towards the sphere's inner surface. Gravity's pull from the spherical shell cancels out inside the shell, so there is no restoring force. 

To create a potential well for the star, one would have to rapidly oscillate the center of mass of the shell around its geometrical center. This way, a (time averaged) potential well can be created to keep the star in place. This would require the sphere to be augmented with rings around its circumference, along which planet-sized masses are rotating at tremendous speed. Angular momentum ought to be conserved, so some counter-rotation by the sphere itself would be needed.

Yes, it would be a sight to behold.

Such a construction is claimed to optimize the amount of energy that can be used by an advanced civilization when restricted to a single star system. All of the fusion energy from the central star can be harvested.

However, it has been argued that ultimately, a civilization does not need energy. It needs to shed entropy. I need to look up another book about that...

ooc: the spherical shell idea was put forward by Freeman Dyson (Science 131, 1667 (1960)), and is called a Dyson sphere.