The Universe Ruler

Around 13.8 billion years ago, the universe was born from an intensely hot and dense point: the Big Bang. In a tiny fraction of a second, it underwent a rapid expansion known as the inflationary period. Afterwards, the universe was filled with a hot, dense soup of particles known as quarks and leptons. These particles are studied in great detail with the Large Hadron Collider (LHC) at CERN.

As the universe continued to expand and cool, these quarks and leptons started to group together, forming protons and neutrons. This was a crucial stage known as the hadron epoch, and happened within the first second of the universe's existence.

Shortly after, during the epoch of nucleosynthesis, protons and neutrons began to combine to form atomic nuclei of the lightest elements, hydrogen and helium. This process of fusion only lasted for about 20 minutes due to the rapid expansion and cooling of the universe. However, it took about 380,000 years until these nuclei could capture electrons to form complete atoms. This resulted in the universe becoming transparent to light.

After hundreds of millions of years, the first stars began to form, lighting up the universe in an era known as the cosmic dawn. From here, galaxies started to form, clustering together under the influence of gravity, bringing us into the galaxy era in which we live now, where stars, planets, and galaxies continue to evolve.