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Title: On the visible size and geometry of aggressively expanding civilizations at cosmological distances

Journal Article · · Journal of Cosmology and Astroparticle Physics
 [1]
  1. Department of Physics, Boise State University, Boise, Idaho 83725 (United States)

If a subset of advanced civilizations in the universe choose to rapidly expand into unoccupied space, these civilizations would have the opportunity to grow to a cosmological scale over the course of billions of years. If such life also makes observable changes to the galaxies they inhabit, then it is possible that vast domains of life-saturated galaxies could be visible from the Earth. Here, we describe the shape and angular size of these domains as viewed from the Earth, and calculate median visible sizes for a variety of scenarios. We also calculate the total fraction of the sky that should be covered by at least one domain. In each of the 27 scenarios we examine, the median angular size of the nearest domain is within an order of magnitude of a percent of the whole celestial sphere. Observing such a domain would likely require an analysis of galaxies on the order of a Gly from the Earth.

OSTI ID:
22524885
Journal Information:
Journal of Cosmology and Astroparticle Physics, Vol. 2016, Issue 04; Other Information: Country of input: International Atomic Energy Agency (IAEA); ISSN 1475-7516
Country of Publication:
United States
Language:
English

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