Universe ID: 10131

The Cosmic Dawn (Still Image Without Titles)

Released on July 3, 2007

About 300,000 years after the Big Bang, the Universe spread out enough that free electrons and protons could form atomic hydrogen. These atoms readily absorb light, thus creating an opaque murky era known as the cosmic Dark Ages. Roughly 900 million years later, the Universe underwent a Reionization Period. The earliest stars and quasars generated enough ultraviolet light to turn hydrogen atoms back into protons and electrons. These areas began as bubbles, continually spreading until light was permitted to travel freely through the Universe. This moment has been dubbed the Cosmic Dawn.

This still image shows the timeline running from the Big Bang on the right, towards the present on the left. In the middle is the Reionization Period, when the initial bubbles caused the Cosmic Dawn.

Credits

Please give credit for this item to:
NASA/STScI

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This item is part of this series:
Astrophysics Stills

Goddard TV Tape:
G2007-007HD

Keywords:
SVS >> HDTV
SVS >> Astrophysics
SVS >> Early Universe
SVS >> Cosmology
SVS >> Big Bang
SVS >> Universe
NASA Science >> Universe