Dyson spheres (The Next Chapter #5)

Our world is energy-hungry. What happens when we are unable to create enough energy that the world demands? Dyson spheres will be here to help.

By Aaron Zhao

The world consumes energy. The world produces energy. The world demands energy. The world is run by energy.

2018 was characterized by significant growth in both primary energy consumption and world energy consumption, with a +2.9% and +2.3% respectively. With a growing population, many living in increasingly developed worlds, it is projected that by 2050, the demand for energy will be almost doubled that of today. In addition, with dwindling amounts of fossil fuels which our current energy system relies heavily upon, this is a perfect time for an energy crisis to be born.

The question surfaces: What is the most effective way to create enough energy for the world in the future? Dyson spheres.

The definition lies in Star Maker, a book by Olaf Stapledon written in 1937, where he first introduced the concept. He wrote that stars would be “surrounded by a gauze of light traps, which focused the escaping solar energy for intelligent use.” However, the name “Dyson sphere” was actually formalized in an article written in 1960 by Freeman Dyson in a Science article, where he had borrowed Stapledon’s idea. In simplest terms, a Dyson Sphere is a megastructure (a very large, artificial structure) that surrounds a star or smaller structures that orbit around a star to absorb its energy output.

How does it work? How much energy could we produce?

The idea of a Dyson sphere is to utilize the energy output of a star. With a solar panel structure built around a star, we are able to capture most of the energy outputted by the star.

To get a sense of how much energy we’re actually missing out on, take a look at these facts.

Right now, the sun is giving off around  3.86 x 10²⁶ watts of energy, most of it going off into space. According to the US Department of Energy, 430 quintillion joules of energy from the sun actually hit the Earth every hour, most of it unused. If we covered the outside of the atmosphere with solar panels, we could generate 166 million gigawatts of power. Imagine how much energy we would have available if a Dyson sphere (that would obviously be much closer to the Sun, therefore absorbing more energy than Earth) surroundeds our sun. We would make more than enough energy to survive the next hundred centuries.

Is it achievable?

The first picture in everybody’s head when they hear the concept of a Dyson sphere is probably a huge solid sphere completely encircling a star. However, this approach is physically impractical. The tensile strength required for a structure of that magnitude is many times more than the one provided by any known material. Also, since the whole structure is bound together, any problems that arise in one part of the sphere will directly impact every other part of the sphere, resulting in tremendous instability.

In addition, the Dyson sphere is unable to keep the star in a fixed spot. That means if the star moves towards the sphere or vice versa, that could cause significant damage and even destruction to the sphere. It must also be able to withstand heavy impacts from objects like asteroids and meteoroids.

Alternatives to a Dyson sphere

So, if a solid structure is unfeasible, what alternative do we have? The idea of a Dyson Swarm has been put forward. Instead of a single solid mass around the star, we break it up into thousands, even millions of tiny parts (solar panels and mirrors), all orbiting the star. While this approach does not fulfill our fanciful daydreams of an imposing, futuristic megastructure (the swarm resembling a patch of space junk), it is a viable approach. While the technology to undertake such a project is still far from being available, in the future, a swarm around the sun could be built in as little as a couple of decades by using robots to mine the materials from nearby planets in our solar system.

Another variant of the Dyson sphere is the Dyson Bubble. Similar to the Dyson swarm, it is composed of many subunits around the star. However, where it differs is that it is composed of statites (satellites that use solar sails to counteract the star’s gravitation pull and remain geosynchronous to its rotation). Think of it as a spherical skeleton, absorbing energy.

The potential Dyson spheres and its variants hold for us is too great to express in words. The only problem is… it’s not going to happen any time soon. But don’t be saddened. Although the feasibility of Dyson spheres is incredibly low (at least now), the concept will undoubtedly influence the space industry in other ways.

Acknowledgement

I would like to thank Alec Jose Rodriguez for introducing the marvellous concept of Dyson spheres to me and inspiring the writing of this article.