Dyson spheres: alien megastructures finally stable under certain conditions 🛸

A recent study reveals that certain configurations of artificial spheres and rings around binary stars could be stable.

The work of Colin McInnes, published in the Monthly Notices of the Royal Astronomical Society, shows that Dyson rings and spheres could maintain their integrity around double star systems. This discovery opens new perspectives in the search for advanced extraterrestrial civilizations.


Freeman Dyson imagined in the 1960s a sphere enclosing a star to capture all its energy. However, such a structure around a single star would be unstable. McInnes explores configurations around two stars, where gravitational forces could balance each other.

The study identifies seven equilibrium points for a ring around two stellar masses. These points allow the ring to remain stable without suffering destructive tensions. Among them, some configurations enclose one or both stars, offering multiple possibilities for such megastructures.

For a Dyson sphere, the results are similar but more complex. A sphere enclosing both stars experiences no net gravitational force, but this configuration is unstable. On the other hand, a sphere surrounding only the smaller of the two stars can find a stable equilibrium.

This research is not purely theoretical. It could guide SETI searches by identifying specific technosignatures. A star accompanied by an object emitting excess infrared radiation could betray the presence of a Dyson sphere.


McInnes also envisions nested structures, such as concentric Dyson spheres. These configurations could be stable in certain star systems. They represent a serious lead for detecting civilizations capable of such constructions.

Finally, this study reminds us that science fiction can sometimes precede science. The ideas of Larry Niven and Freeman Dyson still inspire researchers, proving that imagination is an essential driver of scientific discovery.

What is a Dyson sphere?

A Dyson sphere is a hypothetical megastructure that would completely enclose a star to capture its energy. Proposed by Freeman Dyson in 1960, it would be built from the materials of a planetary system.

This structure would allow an advanced civilization to use all the energy emitted by its star. Dyson estimated that such a construction would be visible through its infrared emission, as the sphere would heat up while absorbing stellar light.

However, a solid sphere around a single star is gravitationally unstable. Recent work shows that configurations around binary systems could solve this problem, offering unexpected stability to these structures.

This research connects astrophysics and the search for extraterrestrial life by proposing specific technosignatures to look for in the Universe.

How can a ring be stable around two stars?

A ring around two stars can find equilibrium points where gravitational forces cancel each other out. Colin McInnes identified seven of these points, allowing a ring to remain stable without disintegrating.

These points depend on the relative positions of the two stars and the ring. Some configurations enclose one or both stars, while others leave both stars outside the ring.

The stability of these structures relies on precise orbital dynamics calculations. They show that the ring must avoid certain areas, called 'collision sets,' where it would eventually come into contact with one of the stars.

These results expand the possibilities for space megastructures by showing that binary star systems could host stable rings or spheres, unlike single-star systems.