Origins of the Universe 101 | National Geographic

The universe encompasses everything from the smallest particles to vast galaxies, raising questions about its origin. The most accepted explanation is the Big Bang theory, which posits that around 13.7 billion years ago, a hot and infinitely dense singularity exploded violently. This explosion marked the creation of all matter, energy, space, and time.

The radiation era followed the Big Bang, characterized by the dominance of energy and fundamental forces. It began with the Planck epoch where only energy existed before gravity separated from a unified superforce. The grand unification epoch saw strong nuclear force break away, leading to rapid expansion during inflationary epoch when particles like electrons and quarks emerged in extreme heat. As temperatures dropped in subsequent epochs, quarks formed protons and neutrons which eventually fused to create helium as the first chemical element.

The matter era marks a significant phase in the universe's evolution, characterized by the dominance of matter. It encompasses three key epochs: the atomic epoch, where electrons combined with nuclei to form hydrogen and helium; the galactic epoch, which saw these atoms cluster into galaxies; and finally, the stellar epoch that initiated star formation. Stars played a crucial role in transforming hydrogen and helium into various elements essential for creating planets and life as we know it today. This intricate development process has laid down an ecosystem rich with complexity while leaving many questions about our universe's origins still unanswered.