12.07.2004

Yeah, Right

There's the old idea of a Dyson Sphere. It captures all of that lost energy emitted by a star. We, on Earth, only receive what tiny bit of sunlight hits our planet's surface but the sun is blowing out a TON of energy every second in all directions, not just in a tiny beam pointed at us. So the Dyson Sphere is a giant artificial ball built around the sun that stores the energy released by the sun.

Now, Earth is a big place. The Sun, well, that's just a truckload or two bigger. So, a sphere right around the sun? Even making one slightly larger than the sun is pretty much a no-go for the foreseeable future. Some believe that the sphere radius should be larger than the Earth's orbital distance (1 AU). Those people need to be hit in the knees with a steel pipe.

In any case, this idea will remain science fiction for a very, very long time. My thought, and I can't have been the only to think this up, is perhaps a baby step in that direction. What about a ring around Earth?

We could build a flat solar collector that faces the sun, and harnesses at least some of the energy that is simply flying unused right by our planet. It would be shaped like a washer or a flattened donut. It doesn't have to be thick, it just has to have a good cross-section so that solar photons can hit it. Each meter of increased radius would capture an exponentially larger amount of energy. It would be crazy!

Now, I know, I know, it's not all roses and jewels. There is the slight problem that a giant ring around the Earth is an unstable proposition. But you could take a percentage of the energy captured and use it to keep the ring positioned right. And, yes, all those massless photons have a momentum that would exert a significant pressure on the ring at the scales we're talking, but again, if the efficiency of the ring is high enough, we could still use some of the energy to push back and have plenty left over. (Or would you? I'm really tired. I'm going to go think about this when I'm awake.)