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Astronomy

Cosmic Reionization: The Epoch When the First Stars Changed the Universe

Quick fact

Cosmic reionization was one of the last major phase transitions of the universe, occurring roughly 150 million to 1 billion years after the Big Bang, when the first stars and galaxies emitted intense ultraviolet radiation that split hydrogen atoms apart, ultimately transforming the universe from opaque to transparent.

Why this is interesting

Imagine a universe wrapped in a thick, ionizing fog where not a single star could shine through. How did that fog clear to reveal the galaxies we see today?

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Cosmic Reionization: The Epoch When the First Stars Changed the Universe

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