The Big Bang: How the Universe Began

The Big Bang marks the moment the universe began expanding about 13.8 billion years ago.
Rather than an explosion in space, it was the rapid expansion of space itself.
In its first seconds, the universe was hotter and denser than the core of any star.
The lightest elements—hydrogen, helium, and traces of lithium—were forged minutes after the Big Bang.
The universe became transparent 380,000 years later, releasing the cosmic microwave background.
Galaxies and stars formed hundreds of millions of years after the initial expansion.
Evidence for the Big Bang includes cosmic background radiation and galaxy redshifts.
The discovery of the expanding universe by Edwin Hubble in the 1920s paved the way for the theory.
Dark matter and dark energy, born in the early universe, still shape cosmic evolution today.
The Big Bang isn’t the “beginning of everything”—it’s the start of the universe as we can observe it.