Aliens control the fastest moving stars in the galaxy?

Long-lived civilizations may have many motives for wanting to move elsewhere in the galaxy. For example, they may need to escape an impending supernova. They may need to scout out our new natural resources.

However, given the vast distances between stars, interstellar travel is extremely difficult and time-consuming. So, instead of leaving their own system, aliens might decide to take their own system with them. The main advantage of accelerating their own star is that they can keep it with them as they travel. They would do this by causing their star to radiate or evaporate in one direction, which would propel the star, along with all the planets, to a new location in the galaxy.

Illustration of a Dyson Sphere, a hypothetical structure that aliens could use to harness the power of stars.

In a recent paper, Clement Vidal, a philosopher at the Vrije Universiteit Brussels in Belgium, pointed out that most stars are not single stars, but rather are in binary systems. This means that we may be missing out on half of the stars that could be artificially accelerated. Vidal took a model system consisting of a neutron star with a low-mass star orbiting it. This setup offers the most flexibility in terms of steering and propulsion.

An alien civilization would have to figure out how to push matter away from the star. The goal would be to get the star to push more matter in one direction than the other. This would create a repulsive force, pushing the binary system in the opposite direction, Vidal explained.

If a civilization placed its machines on or near a neutron star, where the strong gravitational pull would provide a readily available source of energy, they could manipulate the binary system by carefully turning the machines on and off. They could even steer their system into new orbital deviations by changing the direction the machines were facing.

Incredibly, there are real systems in the universe that fit these characteristics, like the 'black widow' pulsar PSR J0610-210 0 and the 'red back' pulsar PSR J2043+1711. Both of these systems exhibit significant accelerations. While they are unlikely to have been caused by alien engineering, they are worth studying, Vidal concludes. At least while they still exist.