Justin C. Feng from the Department of Cosmology and Gravitational Physics at the Institute of Physics of the Czech Academy of Sciences and independent researcher Chris Reiss have co-authored a study on using time dilation from special and general relativity to travel between stars without extreme aging differences between travelers and their home civilization.
In their study titled Redshifted civilizations, galactic empires, and the Fermi paradox, the authors explore scenarios where an entire civilization enters a state of time dilation to synchronize the aging of interstellar travelers with those at home. The work assumes no exotic physics (like negative energies) and uses a civilization's power capacity as a proxy for its technological capabilities, staying within the bounds of general relativity, energy conservation, and known biological acceleration limits.
The study presents three such scenarios. First, a civilization orbiting the galaxy's central supermassive black hole could slow its clocks 100-fold relative to Earth. Second, a galaxy-spanning network of vessels accelerating on straight line paths could achieve a 10,000-fold slowdown, requiring the power equivalent to the output of a single star (a Type II civilization on the Kardashev scale). Third, a more powerful civilization might rearrange the galaxy's black holes into a ring to create a permanent, low-maintenance structure that deflects time dilated vessels into a closed path.
The research also addresses the Fermi paradox by highlighting the vulnerability of such relativistic civilizations. From their perspective, less advanced societies can emerge in a dangerously short time; our own leap from hunter-gatherers to a spacefaring society would seem to take only a year to a vessel experiencing a 10,000-fold time slowdown. Furthermore, for the same vessel, a simple 100 kg object in its path would have the kinetic energy of the Chicxulub impactor thought responsible for the Cretaceous–Paleogene extinction event. For this reason, advanced civilizations might choose to hide, supporting the Dark Forest hypothesis.
The study, published on the arxiv.com preprint website and currently undergoing peer review, has attracted the attention of foreign media and been featured in articles on the portals Universe Today and National Geographic Polska.