'Alien megastructures': How a binary star system could hold the key to stable dyson spheres

The Dyson Sphere Concept


The idea of Dyson spheres, first proposed by physicist Freeman Dyson in the 1960s, involves creating massive structures that enclose a star to capture its energy. Such spheres would provide an enormous surface area and be capable of harnessing vast amounts of solar power, solving the energy needs of an advanced civilisation.

The Fatal Flaw

Dyson's original concept faced a significant problem: if a planet were dismantled to form the shell, the gravitational forces inside the sphere would cancel out. This would mean the sphere would have no stable tether to the star, causing it to drift and eventually collide with the star — an unsustainable outcome.

The Search for Stability


In January 2025, engineer Colin McInnes of the University of Glasgow proposed a theoretical solution. His study, published in Monthly Notices of the Royal Astronomical Society, explores ways to stabilise a Dyson sphere. McInnes suggests that the key to stability may lie in binary star systems, where two stars orbit each other.

Binary Star Systems and Stability

McInnes investigated potential stable points within a binary star system where a Dyson sphere could remain in place without drifting. He found that there are certain configurations where a Dyson sphere could remain stable, though these scenarios still pose challenges, such as the need for a specific mass relationship between the two stars.

A Stable Configuration for Dyson Spheres


McInnes' research identified a particularly stable setup in binary star systems where one star is significantly smaller than the other. In this arrangement, the smaller star’s gravitational influence acts as an anchor, keeping the Dyson sphere in orbit around the larger star and preventing it from colliding with the star it surrounds.

Key Conditions for Stability

For this configuration to work, the smaller star must not exceed one-tenth the mass of the larger star. Additionally, the Dyson sphere must be extremely light and thin to avoid disrupting the gravitational balance of the system. These factors ensure the stability of the Dyson sphere's orbit.

Extraterrestrial Civilisations


While the construction of Dyson spheres by humans remains speculative, McInnes' findings have important implications for the search for extraterrestrial life. Scientists could potentially detect Dyson spheres by looking for large, bright stars with an infrared companion — the signature of heat escaping from a Dyson sphere that surrounds the smaller star of a binary system.