Dyson sphere
Could an advanced civilisation harness the power of stars to sustain their energy needs?
Could an advanced civilisation harness the power of stars to sustain their energy needs?
First proposed by physicist Freeman Dyson in 1960, a Dyson sphere is a hypothetical swarm of satellites that would surround a star in order to harness its energy. Although more commonly known as a Dyson swarm, some people have discussed the possibility that rather than a swarm of satellites, a star could be encased in a solid sphere by a future civilisation – but this is an idea that Dyson himself was keen to stray away from. Indeed, for a planetary system like our own, such a structure would likely require every object in the Solar System other than the Sun to be dismantled and rebuilt into a giant sphere owing to the huge size of the Sun.
Dyson’s initial proposal was suggested as a way that a future civilisation could sate their vast energy needs. As the energy requirements of a civilisation increase, they may require an ever-growing amount of energy, a crisis perhaps solved only by harnessing the power of stars.
This carries further connotations that there could be advanced races elsewhere in the universe that have built such structures. Dyson postulated that these would radiate a large amount of infrared radiation, noticeable even to us here on Earth.
The idea has gained enough ground that the SETI Institute in California has been on the lookout for Dyson spheres, while Fermilab near Chicago has carried out its own analysis of observations from outside the Solar System to ascertain the likelihood of the existence of Dyson spheres. Aside from finding four candidates that were “amusing but still ambiguous and questionable,” though, nothing too promising has been found.
While fun to imagine, the logistics of a Dyson sphere are also quite far-fetched. Taking the solid shell idea, a structure would be thin – at perhaps just a few tens or hundreds of metres thick – with its membrane covered in solar panels, but it would still be many times more massive than Earth. Placed around a star, it would have little chance of keeping its structural integrity; if made to rotate so as to keep it in ‘orbit’ around the star, the areas around its artificial equator would be stable, but at the poles, where there is no rotation, the structure would succumb to the forces of gravity and collapse.
This is why Dyson favours the swarm idea. With this, many thousands of solar-energy-gathering satellites would be placed around the star. They would then beam their energy to a central hub to be utilised by a civilisation. Using separate satellites, all in orbit around the star, the structure would remain intact and huge amounts of energy could be transferred from the star.
While this particular structure might seem impractical, something on a smaller scale could feasibly do a similar job. For example, some theories suggest that a large solar-gathering spacecraft placed between Earth and the Moon would be able to absorb huge amounts of power that could be beamed to our planet.
Known as space-based solar power (SBSP), this is something that science-fiction writers have favoured, and is a much more promising technology than an entire Dyson sphere. However, perhaps many thousands of years in the future when we become interstellar explorers, it may be necessary to find huge resources of energy, and as far as we know there’s nothing better than an entire star.