Two tiny comments from me:
Leo62 said:
The Big Bang is widely accepted as the dominant theory of the creation of the universe. It can never be inconclusively proven, but there is a lot of circumstantial evidence to back it up. The Big Bang suggests that the universe was created in a single cataclysmic event, an explosion, almost 14 billion years ago. In the first few seconds after the Big Bang, the four forces, atomic nuclei and basic elements all took shape
You've put "inconclusively" where, in fact, you mean "conclusively". Also I think you should say what the four forces are.
Then some rather more erudite comments from my husband!:
Leo62 said:
Another piece of evidence, Cosmic Microwave Background Radiation (CMB), which was predicted by the Big Bang theory, has also been found and measured. This is a kind of leftover from matter and antimatter annihilations in the early moments after the Big Bang.
No. The universe is thought to have been infinitely hot at the instant of the big bang and has been cooling down ever since. Within the first few seconds of the bang, matter was formed, in particular protons & electrons which combine to form hydrogen atoms. But for the first 300,000 years the universe was still so hot and dense that hydrogen atoms couldn’t form. It also meant that, effectively, the universe was opaque. 300,000 years after the bb, the universe became cool enough for electrons & protons to come together to form hydrogen atoms. At that point the universe became transparent and light could suddenly travel great distances. The microwave background is the remaining glow of the fireball that became visible 300,000 years after the bb. Since then the expansion of the universe has shifted this radiation so far to the red end of the spectrum that it appears like a very cool glow visible from all parts of the universe, as though all the universe is glowing at 3 degrees above absolute zero.
Leo62 said:
Every matter particle has a matching antimatter particle or antiparticle.
This should read "Every type of matter particle . . ."
Leo62 said:
When a matter particle meets its antimatter partner, they annihilate each other in pure energy, which then goes on to form other kinds of particles.
This should read "which can go on to form other kinds of particles". It doesn't necessarily do so.
Leo62 said:
Theoretically, physicists are sure that antimatter exists.
Leave out the "theoretically" - it's a fact. As you point out, antimatter has been created.
Leo62 said:
The strange thing is that our universe is made up entirely of matter.
It appears to be, but we don't know for certain that it is.
Hope this helps!