The Dark Ages ended with the Epoch of Reionization, where the first stars and galaxies ignited, emitting ultraviolet radiation that ionized the neutral hydrogen and made the universe transparent to light, allowing the Cosmic Microwave Background radiation to travel freely. This era, known as Big Bang Nucleosynthesis, occurred roughly between one second and three minutes after the initial expansion.
Cosmic Dawn Timeline: The Epoch of Reionization and the Universe's First Light
The universe underwent a period of cosmic inflation during the first fraction of a second, expanding exponentially faster than the speed of light to smooth out irregularities and establish the uniform backdrop we observe today. During this brief window, the universe forged the lightest elements, primarily hydrogen, helium, and trace amounts of lithium, establishing the primordial composition that would later fuel star formation.
Key Elemental Abundances Element Approximate Abundance Hydrogen ~75% by mass Helium ~25% by mass Lithium & Beryllium <1% by mass The Dark Ages and the First Light Following nucleosynthesis, the universe entered a period known as the Dark Ages, which lasted for millions of years. This singularity did not explode into pre-existing space; rather, space itself began to expand from this quantum state.
Cosmic Dawn Timeline: The Epoch of Reionization and First Light
The life cycles of stars—fusion, collapse, and supernova explosions—further enriched the interstellar medium with heavier elements like carbon, oxygen, and iron, essential building blocks for planets and life. This framework describes the evolution of the universe from its initial moment of hot, dense expansion to the present day, where galaxies drift apart in a vast, cooling expanse.
More About Big bang theory stages
Looking at Big bang theory stages from another angle can help expand the discussion and give readers a second clear paragraph under the same section.
More perspective on Big bang theory stages can make the topic easier to follow by connecting earlier points with a few simple takeaways.
