How and when was the universe made? That is the question people have asked from the first human being without getting an answer. Still there is no sign of coming any closer to an answer.
Many astronomers today think that a big explosion caused the universe to start between 15 and 20 trillion years ago. Every particle in the universe was together as a single, very hot, dense mass. This mass exploded, and the scientists call the phenomenon: the “Big Bang”.
We almost know how the universe was 100,000 years after the “Big Bang,” and we have an idea of how it was after a couple of minutes. It has to have been chaotic with radiation because separate particles could not have existed there. After a billionth part of a second, maybe the first and the basic elements came to be. The temperature had then fallen maybe 100 billion degrees.
Plasma, which is a very warm gas of electric ally charged particles and ions, filled the universe in the plasma period. This period ended about 100,000 years after the “Big Bang.” The temperature had now fallen considerably and it was now free for protons, neutrons, electrons to exist. Another particles created the first atoms after approximately one million years. After that, the atoms created fog, stars and galaxies. That’s the way the universe became what it is today.