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Cosmology concept

Early Dark Energy

A proposed but unconfirmed resolution of the Hubble tension in which a small, transient dark-energy-like component acts in the early universe around the time of recombination, shrinking the sound horizon and so raising the Hubble constant inferred from the CMB toward the local value. It is one of several competing ideas — alongside extra relativistic species and modified gravity — and none is yet established.

Highlights

  • One proposed, unconfirmed resolution of the Hubble tension

Knowledge connections

Sources

The primary and reference sources this topic draws on.

  • NASANational Aeronautics and Space Administration

    Mission data, planetary science, space telescopes, and public-domain imagery.

    Most NASA-produced imagery is in the public domain; individual items are checked for usage terms before publication.