Cosmology Today

David N. Spergel

Research output: Contribution to journalArticlepeer-review

4 Scopus citations


We seem to live in a simple but strange universe. Our basic cosmological model fits a host of astronomical observations with only five basic parameters: the age of the universe, the density of atoms, the density of matter, the initial “lumpiness” of the universe, and a parameter that describes whether this lumpiness is more pronounced on smaller physical scales. Our observations of the cosmic microwave background fluctuations determine these parameters with uncertainties of only 1 to 2 percent. The same model also provides an excellent fit to the large-scale clustering of galaxies and gas, the properties of galaxy clusters, observations of gravitational lensing, and supernova-based measurements of the Hubble relation. This model implies that we live in a strange universe: atoms make up only 4 percent of the visible universe, dark matter makes up 24 percent, and dark energy–energy associated with empty space–makes up 72 percent.

Original languageEnglish (US)
Pages (from-to)125-133
Number of pages9
Issue number4
StatePublished - Nov 1 2014

All Science Journal Classification (ASJC) codes

  • Arts and Humanities (miscellaneous)
  • Social Sciences (miscellaneous)
  • Political Science and International Relations
  • History and Philosophy of Science


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