Beginning universe Theories
Big Bang Theory- In the big bang theory it states that 12 to 14 billion years ago the universe was just a hot, dense piece of matter that was only a few millimeters across. Then it exploded, so to speak, and started expanding rapidly. Then as it grew larger its rate of expansion slowed little by little, but is still expanding today at a much slower rate.
Oscillating Theory- The oscillating theory is a combination of both the big bang theory and the big crunch (where the univerese dies when all the stars die and then implodes). In this theory the big bang creates the universe and then the big crunch destroys it. But it doesn't stay that way, instead another big bang occurs, then a big crunch. This is said to repeat over and over creating more and more univereses.
Steady State Theory- In the steady state theory, the universe is constantly expanding but maintains a constant average density by creating matter to form new stars and galaxies at the same rate old stars and galaxies become unobservable due to increasing distance from the univers's expansion. This theory also states that the universe has no beginning or end in time and that galaxies of all galaxies are intermingled.
Most Accepted Theory- Out of these three theories the most accepted theory is th Big Bang Theory which would mean the universe would be between 12 to 14 billion years old. This theory is most likely the most accepted because in the Big Bang it states that the universe is constantly expanding, which, by using the technology of today, is what is happening in the universe now as we notice galaxies moving farther apart from eachother.