Level 2

Timeline of the Big Bang

Particle Accelerator

What happened right after the Big Bang?
Scientists try to answer this with particle accelerators. These are underground devices that make tiny particles move very fast. They use electric and magnetic fields to do this. Scientists discovered new tiny particles in these tunnels.

Subatomic Particles

Subatomic particles are smaller than atoms. Some are part of atoms, others are found only in stars or labs. They are studied in a science called particle physics.

Cosmic Inflation

Around 10-37 seconds after the Big Bang:
The universe was very hot and dense. It expanded and cooled rapidly. A phase called cosmic inflation made it grow very fast in size.

The Early Universe

The universe had high energy and temperature. It was the same in all directions. It expanded quickly, making it cooler.

Development stages of the universeFigure A: Development stages of the universe. Time is on the horizontal axis.

Antiparticles

After inflation, the universe changed:
It had quark-gluon plasma and other tiny particles. These particles moved at high speeds. Particle-antiparticle pairs were created and destroyed in collisions.

What Are Antiparticles?

An antiparticle is like a normal particle, but with opposite properties. For example, it might have the opposite charge.

Annihilation

Around 10-11 seconds after the Big Bang:
The universe cooled down. Quarks and gluons formed baryons, like protons and neutrons. These make up atoms. A small excess of matter over antimatter led to the dominance of matter.

The Breaking of Symmetry

The universe’s forces and particles took their current form through phase transitions. Scientists simulate these conditions in labs, like CERN in Switzerland.

Big Bang Nucleosynthesis

Around 1 second after the Big Bang:
Electrons and positrons annihilated each other. The universe's energy was dominated by photons. Neutrons fused with protons to form deuterium and helium.

Formation of Nuclei

A few minutes into expansion, the temperature was a billion degrees Kelvin. Neutrons and protons formed deuterium and helium. Most protons stayed as hydrogen nuclei.

Cosmic Microwave Background Radiation

Around 379,000 years after the Big Bang:
The universe cooled down. Electrons bonded with atomic nuclei, forming the first atoms, mainly hydrogen. Space became transparent, and radiation moved freely.

Importance of Radiation

This radiation is known as the cosmic microwave background radiation. It shows us the early universe.

Conclusion

The universe didn’t always have subatomic particles. They formed through a complex process over millions of years. These particles eventually formed the universe as we know it today.

 
R I M F
Book Part 1, Topic B, Chapter 3, page 6-level2: Timeline of Big Bang