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Cosmic epoch · Cosmology

The Cosmic Dark Ages

Cosmology & UniverseStrong Evidence

Definition

The period after recombination and before the first stars, when the Universe was filled with neutral gas and no sources of light.

Scientific overview

After the CMB was released, the Universe entered a dark, starless era of neutral hydrogen and helium slowly drawn together by gravity and dark matter. It ended when the first stars ignited.

Open questions

  • Exactly when did the first luminous objects form?

Rests on

Knowledge connections

Sources & references

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.