Theorizing on how all the existing matter came to be is a job that keeps on giving. It will be many years, until it is known exactly how the universe sprang into life. But, answers do seem to be getting more on target and scientists are quite convinced they are getting closer to knowing. But, there are still many other possibilities that can fit the physics model and prove to be a close match as well.
Following is a breakdown of the most possible theories discussed today and the likelihood of each as discussed and studied by cosmologists and astrophysicists.
The Big Bang Theory
Widely accepted and the current model for how the universe started, The Big Bang Theory is the best explanation scientists have today. This theory states that the universe started out of what is known as a singularity 13.7 billion years ago. A singularity is a zone of infinite density, but not much else is known about it, as it is still a mystery, explains Jenna Levin, Center for Particle Astrophysics, UC at Berkley, California.
Moments after that explosion the universe started inflating faster than the speed of light as particles interacted with one another. In a process that took billions of years to evolve the universe that exists today formed. Astronomers have discovered in recent years that the universe is still expanding and this expansion is accelerating.
The Big Bounce Theory
This is a theory that states there was actually something before the Big Bang. It suggests that another universe went through a Big Crunch and then 'bounced' back and gave birth to this universe, says Scientific American Science Editor Roger Highfield in his article "Before the Big Bang-the Big Bounce".
The Big Bounce seems to solve the problem of the unknown singularity factor of the Big Bang. It takes away the notion that the universe came to be from an infinite dense area with no mass, which goes against all mathematical notions.
Based on Loop Quantum Gravity, it combines Einstein's theory of gravity with that of quantum theory, which could provide light on the question of what was there before the Big Bang happened, says Dr. Martin Bojowald, Assistant Professor of Physics at Penn State University.
Cyclic Universe Theory
As the name implies, a cyclic universe explodes into existence in a Big Bang, and crunches out of existence over and over again in an endless cycle. This theory is an alternative to the Big Bang that has gotten much attention from scientists after Princeton physicist Paul Steinhardt and Neil Turok of Cambridge University published an article on it in the Science online edition.
The Cyclic Universe Theory could explain the mystery of why the 'cosmological constant' is accelerating, which the Big Bang theory could not account for, says Ker Than in his article "Recycled Universe: Theory Could Solve Cosmic Mystery" on Space.com. It also answers the long-standing question of what was before the Big Bang.
Steady State Theory
Another alternative to the Big Bang theory is the Steady State theory. This theory was developed by Fred Hoyle and Thomas Gold in 1949. Ironically, Fred Hoyle was the person who coined the term 'Big Bang', sort of as a way to make fun of a theory he did not advocate.
Steady State theory claims that the universe had no beginning, but it created new matter as older galaxies moved apart. However, discovery of the CMB (Cosmic Microwave Background radiation) became a big blow against Steady State, although Hoyle maintained that the background radiation could have originated without a Big Bang, states Chandra Wickramasinghe, of the Cardiff University Center for Astrobiology.
As cosmologists and astronomers keep researching, there will undoubtedly be many more theories to come. These new findings are what make the mysteries of the universe so exciting and what keep the search for knowledge an important issue for people who love learning about what lies beyond.
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