A new paper by Oxford’s Future of Humanity Institute authors Stuart Armstrong and Anders Sandberg argues that spreading intelligent life across galaxies is far less daunting than conventional wisdom suggests. By modelling Dyson‑sphere construction, self‑replicating probes and modest energy budgets, they claim a star‑spanning civilization could launch a intergalactic colonisation wave that reaches the observable universe within human‑scale timeframes, over distances measured in millions of light‑years.

The authors first demonstrate that humanity, given advances in automation and probe replication, could feasibly embark on such a project within the foreseeable future. Scaling the same calculations to millions of potential host galaxies yields a scenario where countless extraterrestrial societies should already have arrived, tightening the classic Fermi paradox by extending the silence beyond the Milky Way, across cosmic timescales and across intergalactic distances.

Their analysis also tackles practical obstacles such as deceleration, interstellar medium collisions and probe durability over billions of years, concluding that these challenges add only marginal cost. By framing intergalactic expansion as a modest engineering problem, the paper forces SETI researchers to reconsider search strategies that ignore Type III civilizations and prompts a reevaluation of existential‑risk models in long‑term planning.