examining hawking’s alien dyson sphere

Would aliens actually want to build a Dyson Sphere? It wouldn't be out of reach for them, but they might get a lot less power out of it, with a lot less utility than it seems at first glance...
building a dyson sphere

Not too long ago, Discovery Channel aired a two part program featuring Stephen Hawking’s musings on alien life and time travel. And while we’ve already covered a few objections to his ideas of alien hordes potentially knocking on our doors, Hawking said something very interesting about the technology which highly advanced extraterrestrials might use, particularly how they could harness enough energy for interstellar travel. According to the physicist, clever aliens could use a flotilla of solar panels to harness, beam, and focus the energy of an entire sun, channeling it into beams that could open wormholes for interstellar travel. Just think of a compact, star orbiting Dyson sphere and you’ll probably get the picture. On paper, it seems like a decent concept. But in reality, trying to use quadrillions of solar panels to soak up most of a star’s power output simply doesn’t work, and any attempt to do something like it would run into huge logistical problems.

Believe it or not, if you run the numbers, the actual task of building all those solar panels isn’t out of reach for an advanced alien species. Granted, they’d need an industrial capacity a thousand times greater than ours and consider price to be no object, but we’re talking about an amount of material on par with a small asteroid rather than something totally unrealistic. Launching all those panels and building power stations which would absorb the intense, focused beams channeled towards them by a swarm of mirrors is another matter, but we could overlook that for now since there’s a pressing problem to consider with the very notion of absorbing all, or most of a star’s light. Imagine living on a planet where the sun shines with just 5% of its previous intensity. Anything living on that world would be frozen solid and any civilization that blocked the vast majority of its own sunlight would very quickly find itself living in a dead, icy desert. Now, if the planet in question is already dead, this kind of thing wouldn’t matter. But if that’s the case, we’d also expect the alien civilization to flee to greener pastures, or go extinct as their world slowly died.

It would be much safer from our hypothetical aliens to put their solar panels far beyond their orbit, collecting a good deal of sunlight which either doesn’t reach them at all, or isn’t necessary for their planet’s survival. But a distant solar panel array means less power to collect per panel and an immense grid to maintain. And what about sending all the energy collected back to the aliens’ power stations? As the light bounces around all the mirrors and travels for tens of millions of miles, the beams would diffuse and a significant percentage of what the panels collected would be lost. Consider the problems with space solar technologies and multiply them by a factor of trillions. Sure, a grid that big could easily power an entire planet. But the grid would be extremely inefficient and Hawking’s idea of using something like this to create a time and space tearing beam would be downright impossible. Even if the grid was 100% efficient, it couldn’t gather enough energy to pierce the fabric of space and time and create wormholes big enough for anything even resembling a spacecraft to pass. The otherworldly civilizations in question would have a much easier time building black hole engines and fusion reactors to reach other stars rather than assembling a giant, inefficient grid of solar panels and mirrors.

# science // alien civilizations / dyson spheres / space solar power


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