1997/02/25 by Max Tegmark · 2 voices · 10 citations
Earth and Planetary Sciences · Physics and Astronomy · #Black Holes and Theoretical Physics #Cosmology and Gravitation Theories #Earth Systems and Cosmic Evolution #gr-qc #hep-ph #hep-th
paper · pdf · doi:10.1088/0264-9381/14/4/002
published as Class.Quant.Grav.14:L69-L75,1997 · Minor modifications to match published version. 5 pages. Color figures and related links at http://www.sns.ias.edu/~max/dimensions.html (faster from the US), from http://www.mpa-garching.mpg.de/~max/dimensions.html (faster from Europe) or from [email protected]
arxiv published 1997/02/25 · openalex publication_date 1997/04/01 · arxiv created 1997/04/05 · arxiv updated 2010/04/06 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/30
Some superstring theories have more than one effective low-energy limit, corresponding to classical spacetimes with different dimensionalities. We argue that all but the 3+1-dimensional one might correspond to ``dead worlds'', devoid of observers, in which case all such ensemble theories would actually predict that we should find ourselves inhabiting a 3+1-dimensional spacetime. With more or less than one time-dimension, the partial differential equations of nature would lack the hyperbolicity property that enables observers to make predictions. In a space with more than three dimensions, there can be no traditional atoms and perhaps no stable structures. A space with less than three dimensions allows no gravitational force and may be too simple and barren to contain observers.