CHAPTER 01

The Big Bang

Approximately 13.8 billion years ago, all matter, energy, space, and time erupted from an unimaginably small, hot, and dense singularity. This was not an explosion in space — it was an explosion of space itself.

13.8 Billion Years
Age of Universe
~10³² Kelvin
Initial Temperature
Smaller than a Proton
Initial Size
Faster than Light
Expansion Speed

What Was the Big Bang?

The Big Bang was not an explosion in an existing void — it was the very beginning of space and time. Before it, there was no "before." All the laws of physics, matter, and energy we observe today were contained in a state of infinite density called a gravitational singularity.

The evidence for the Big Bang is overwhelming: the expanding universe observed by Edwin Hubble in 1929, the Cosmic Microwave Background (CMB) radiation discovered in 1965, and the precise abundance of light elements like hydrogen and helium all point to a hot, dense origin.

Albert Einstein's General Theory of Relativity, combined with observations by Hubble, Georges Lemaître, and others, laid the foundation for the Big Bang model. Today it is the most well-tested and supported cosmological theory in science.

The Singularity

At T=0, the universe existed as a singularity — a point of infinite density, infinite temperature, and zero volume. The Planck temperature (10³² K) marks the highest temperature physically meaningful in our current models. Beyond this point, our current physics breaks down entirely. String theory and loop quantum gravity attempt to describe what happened at or before this moment, but no consensus has been reached.

The First 3 Minutes — A Timeline

10⁻⁴³ s
Planck Epoch
The universe is a quantum foam of spacetime. Physics as we know it breaks down. Temperature: 10³² K.
10⁻³⁶ s
Grand Unification
Three of the four fundamental forces (strong, weak, electromagnetic) are unified into one superforce.
10⁻³² s
Cosmic Inflation
The universe expands exponentially — from sub-atomic to macroscopic size in a fraction of a second.
10⁻¹² s
Electroweak Epoch
The electromagnetic and weak nuclear forces separate. Matter begins to dominate over antimatter.
10⁻⁶ s
Quark Epoch
Quarks and gluons condense into protons and neutrons as the universe cools to 10¹² K.
3 min
Nucleosynthesis
Protons and neutrons fuse to form deuterium, helium-4, and trace lithium. The light elements are born.

The Cosmic Microwave Background — Echoes of Creation

At 380,000 years old, the universe had cooled enough for electrons to bind with protons, forming neutral hydrogen atoms. This allowed photons to travel freely for the first time — creating the Cosmic Microwave Background (CMB). This ancient light, now red-shifted to microwave frequencies, bathes the entire universe at a temperature of 2.725 K. Mapped in extraordinary detail by the WMAP and Planck satellites, the CMB is our most direct snapshot of the early universe.

← HomeNext: Early Universe →