Webb image archive
First Stars: Timeline of the Universe
Although we are not sure exactly when the first stars began to shine, we know that they must have formed sometime after the era of Recombination, when hydrogen and helium atoms fo...
- Date
- Dec 13, 2023
- Observatory
- James Webb Space Telescope
- Credit
- NASA / ESA / CSA / STScI
- Archive ID
- 4352
Although we are not sure exactly when the first stars began to shine, we know that they must have formed sometime after the era of Recombination, when hydrogen and helium atoms formed (380,000 years after the big bang), and before the oldest-known galaxies existed (400 million years after the big bang). The ultraviolet light emitted by the first stars broke down the neutral hydrogen gas filling the universe into hydrogen ions and free electrons, initiating the era of Reionization and the end of the Dark Ages of the universe.