Big Bang:
Some astronomers think the Universe started with the Big Bang about 14 billions years ago. At this moment, it was inside the bubble and it was very small. The bubble was hotter and very dense. And then exploded, time,space and matter started with the Big Bang.
In a very small time the universe grew to bigger than a galaxy and it is still expanding today. As the universe expanded and cooled the particles of matter and antimatter were created. These two types of particles destroyed each other. More stable particles called protons and neutrons appeared in one second.
Afterwards in very small time the temperature dropped below 1 billion degrees Celsius. Now protons and neutrons can join and create hydrogen and helium nuclei.
GIPHY:
via GIPHY
