A technologically advanced alien civilization is capable of creating "star farms" to combat the energy deficit caused by the expansion of the universe. This will allow it to exist for a maximum of 100 trillion years, when star formation processes stop. This is the conclusion reached by the American astrophysicist Dan Hooper of the University of Chicago and the Enrico Fermi National Accelerator Laboratory (Illinois). The scientist's article is uploaded to the arXiv preprint repository.
In about 100 trillion years, the accelerated expansion of the Universe will make it impossible to observe not only the traces of the Big Bang, but also many galaxies, since the light from them will not have time to reach the observer. These objects will be so far away that, according to Hubble's law, they will move away from the Earth at a speed exceeding the speed of light. As a result, separate regions of the Universe will be completely isolated from each other by the cosmological horizon.
According to the scientist, any technologically advanced civilization located in such an area must consume a huge amount of energy, but it will gradually exhaust all resources available to it. To prolong their existence, aliens must be able to move stars from other galaxies, which in the future will be outside the cosmological horizon, and collect them in their home galaxy.
To make the most of the light from the star, civilizations can erect astro-engineering structures like Dyson's spheres. At the same time, Hooper does not say how the transportation will be carried out.
However, other researchers believe that such activities of hypothetical aliens are meaningless, since natural "storage" of stars already exist in space. For example, large clusters of galaxies have billions of stars, and their gravity is sufficient to prevent dispersal due to the expansion of the universe. Alien civilizations, therefore, may simply migrate to more star-rich regions.
