TIME

First Atoms

≈ 380,000 years after the Big Bang

Illustration of the early universe: a glowing golden cloud of hot gas on the left thins into dark space, where three small atoms, each a bright nucleus with one electron on a thin orbit, drift to the right.

Cosmic TimeFirst Atoms

Electrons and nuclei combine.

About 380,000 years after the Big Bang the universe cooled enough for electrons to join atomic nuclei. The first atoms were mostly hydrogen and helium, and light could finally travel freely.

This is the same moment as First Light. Estimates run from 375,000 to 380,000 years.

380,000 years after the Big Bang, placed on the scale of its era on a line leading toward now.

Era
Cosmic Time
Period
≈ 380,000 years after the Big Bang
Edition
1/1
Status
Not Released
Explore on TimelineBack to Collections
Background artwork

An original illustration generated for TIME with an AI image model, 2026. An artistic reconstruction of the first atoms forming as the early universe cooled. The atoms are drawn as simple orbiting models for clarity. No picture of this moment exists.