Cosmic Timeline Revealed

The history of the universe unfolds in distinct phases. The first 380,000 years were opaque — the universe was a hot plasma too dense for light to travel through. Then atoms formed and the universe became transparent, releasing the CMB. The next few hundred million years were the cosmic dark ages — no stars had yet formed.

The first stars ignited roughly 200 million years after the Big Bang, ending the dark ages and beginning the epoch of reionization. Galaxies assembled over the next few billion years, with star formation peaking when the universe was about 3 billion years old. Today, at 13.8 billion years, star formation has declined significantly.