~380,000 years to a few hundred million years after the Big BangReputable sourceWell documented

The Cosmic Dark Ages

On the timeline · around ~380,000 years to a few hundred million years after the Big Bang · Cosmic Dawn

What happened

After the cosmic microwave background was released, the universe entered the 'Dark Ages' — a long, starless era filled with neutral hydrogen gas and no sources of visible light.

Why it matters

For hundreds of millions of years the cosmos was truly dark, until gravity slowly gathered gas dense enough to ignite the very first stars.

Sources

NASA Goddard Space Flight Center. The End of the Dark Ages: First Stars and Reionization · Reputable source

Part of a timelineThe Universe24 events · 13.8 billion years in the making — from the Big Bang to the galaxies of today, the story of the cosmos, every milestone sourced.View all →