So let me tell you about my idea for a satellite sun.
You take a bunch of matter, not a great deal-just a few thousand tons-and you collapse it into a black hole (how you do this is another matter). Because the black hole is made from so little mass, it will be tiny. This is great, because it means it will have a very small event horizon: the gravitational effects of a few thousand tons are not considerable. What is not great is that because small black holes emit short wavelength Hawking radiation. Short wavelengths are deadly: they are what Gamma ray bursts and cosmic rays are made of. They are high energy and shielding is needed to survive them.
Now, make some iron plates. Build them by melting the iron, and pouring it all around a system of pipes made from ultra-heat resistant material; perhaps graphene will do. Then put these plates in close orbit around the black hole.
The powerful radiation will melt the iron on the inward-facing sides. The glowing hot, liquid iron then travels up the pipes to the outer sides, where it can cool down against the vacuum of space. As it cools, it emits energy in the form of heat and visible light (some sort of intervention will be needed to pump the cooling iron back down towards the inner side, before it solidifies and becomes unmanageable).
Effectively, the iron has been used as a ‘step down’ transformer for the black hole’s radiation. And that's it! With something the mass of a naval destroyer, you can (with sufficient technology) create a small, orbiting, satellite sun. Why would this be useful?
1 - Efficiency. We like to think of suns being these wonderful sources of energy; and they are. However, to efficiently tap all the energy the sun puts out, we would have to build Dyson spheres around them. This is a fantastic expenditure of resources however you choose to build one. Let's say you do: now the second problem is that the nuclear fusion going on in stars is not very efficient, either. Fusion releases barely a third of a percent of the energy in matter. It is only worth tapping a star for power because stars are already there!
Black holes however, convert 100% of energy into matter, which they bleed away through Hawking radiation as they slowly evaporate. If a culture is serious about energy efficiency, it will turn to black holes, built and placed as it needs.
2 - Convenience. Sun are just not helpful. They have huge gravity wells which makes traveling to and from the inner system, expensive in terms of energy and time. Their habitable zones are also quite constrained – beyond where water can remain liquid, its worlds are too cold for surface life as we know it.
With satellite suns, any world anywhere can be warmed and lit. Larger planets may need 2 or 3. Dwarf planets and moons though, perhaps just one. All the worlds of the Kuiper belt and the Oort cloud are game, and probably most important of all, the interstellar void itself. As many as half of all planets created may reside in these spaces, bounced out of their home systems by gravitational tugs of war:
A culture that liberates itself from stars could live side-by-side along empires that haven’t; just as we share this planet with others we pretend we have dominance over, like ants and bacteria. As on Earth, these cultures would only come into conflict when their realms brush up against each other.
Sun satellites cannot be used to terraform every world in the galaxy, however. They may melt ice into water and heat snowbanks into atmospheres, but any life that evolves or settles on these heated worlds would be destroyed by radiation from space if those worlds lack strong magnetic fields.
The use of black holes manufactured, or otherwise, has been put forward before by many writers and scientists. There is Benford and Niven’s shipstar for example, and the Kugelblitz, a black made from light (and a more likely precursor for a satellite sun):
However, as far as I know (and please let me know if I'm wrong!) this is the first time a black hole radiation ‘step down’ transformer has been suggested, or at least, suggested as a terraforming solution.
I write about a satellite sun in a short story that’s in a military SF collection that came out this month, Backblast Area Clear. In it, a group of soldiers attempt to rescue some stranded scientists who have been studying one such artifact, in a system controlled by a hegemonizing swarm.
Backblast Area Clear is already an Amazon bestseller (hooray!), and has excellent stories from the likes of military SF veterans as Chris Fox, JR Handley, and Chris Winder. If you'd like to give it a go, you can find it here:
I hope you enjoyed reading about the satellite sun concept. Do let me know if you have come across it anywhere else!
Take care, and Happy New Year,