What is the timeline of the universe? when did it all begin?
Most scientist agree that our mysterious universe started with the Big Bang app. 13,7 billion years ago.
They have been able to go back and estimate what happened one billionth of a second after the Big Bang as explained in this video:
In the first phase of the universe -during the first second or so - protons, neutrons, and electrons formed when photons collided and converted their energy into mass. The temperature of the universe cooled during this time and app. three minutes after the Big Bang, protons and neutrons started to combine and form the nuclei of heavier elements, like helium.
It would pass almost 300.000 years before the next major phase would take place. Atomic nuclei were created. The temperature of the universe fell to the point where nuclei could combine with electrons to create neutral atoms.
App. 400 million years following the Big Bang, the first stars began to form.
Next, app. 1 billion years following the Big Bang the first galaxies started to evolve. From there on to present day the further formation of galaxies as well as the solar system took place.