Dodecahedral space topology as an explanation for weak wide-angle temperature correlations in the cosmic microwave background

• Published in: Nature (London) 2003-10, Vol.425 (6958), p.593-595
• Main Authors: Luminet, Jean-Pierre, Weeks, Jeffrey R., Riazuelo, Alain, Lehoucq, Roland, Uzan, Jean-Philippe
• Format: Article
• Language: English
• Subjects: Anisotropy; Astronomy; Cosmology; Earth, ocean, space; Exact sciences and technology; Humanities and Social Sciences; letter; Microwave communications; multidisciplinary; Particle-theory and field-theory models of the early universe (including cosmic pancakes, cosmic strings, chaotic phenomena, inflationary universe, etc.); Science; Science (multidisciplinary); Stellar systems. Galactic and extragalactic objects and systems. The universe; Temperature; Topology
• ISSN: 0028-0836; 1476-4687
• DOI: 10.1038/nature01944

The current ‘standard model’ of cosmology posits an infinite flat universe forever expanding under the pressure of dark energy. First-year data from the Wilkinson Microwave Anisotropy Probe (WMAP) confirm this model to spectacular precision on all but the largest scales 1 , 2 . Temperature correlations across the microwave sky match expectations on angular scales narrower than 60° but, contrary to predictions, vanish on scales wider than 60°. Several explanations have been proposed 3 , 4 . One natural approach questions the underlying geometry of space—namely, its curvature 5 and topology 6 . In an infinite flat space, waves from the Big Bang would fill the universe on all length scales. The observed lack of temperature correlations on scales beyond 60° means that the broadest waves are missing, perhaps because space itself is not big enough to support them. Here we present a simple geometrical model of a finite space—the Poincaré dodecahedral space—which accounts for WMAP's observations with no fine-tuning required. The predicted density is Ω 0 ≈ 1.013 > 1, and the model also predicts temperature correlations in matching circles on the sky 7 .