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Galactic civilizations: Population dynamics and interstellar diffusionThe interstellar diffusion of galactic civilizations is reexamined by potential theory; both numerical and analytical solutions are derived for the nonlinear partial differential equations which specify a range of relevant models, drawn from blast wave physics, soil science, and, especially, population biology. An essential feature of these models is that, for all civilizations, population growth must be limited by the carrying capacity of the environment. Dispersal is fundamentally a diffusion process; a density-dependent diffusivity describes interstellar emigration. Two models are considered: the first describing zero population growth (ZPG), and the second which also includes local growth and saturation of a planetary population, and for which an asymptotic traveling wave solution is found.
Document ID
19790011801
Document Type
Contractor Report (CR)
Authors
Newman, W. I. (Cornell Univ. Ithaca, NY, United States)
Sagan, C. (Cornell Univ. Ithaca, NY, United States)
Date Acquired
September 3, 2013
Publication Date
December 1, 1978
Subject Category
ASTROPHYSICS
Report/Patent Number
CRSR-711
NASA-CR-158245
Funding Number(s)
CONTRACT_GRANT: NGR-33-010-101
Distribution Limits
Public
Copyright
Work of the US Gov. Public Use Permitted.

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