The Big Bang (comparisive of two major theories)

Essay by Matt PrzybylskiHigh School, 11th grade April 1996

download word file, 4 pages 4.1 1 reviews

Downloaded 172 times

Big Bang

It is always a mystery about how the universe began, whether if and when it will end.

Astronomers construct hypotheses called cosmological models that try to find the answer.

There are two types of models: Big Bang and Steady State. However, through many

observational evidences, the Big Bang theory can best explain the creation of the


The Big Bang model postulates that about 15 to 20 billion years ago, the universe

violently exploded into being, in an event called the Big Bang. Before the Big Bang, all

of the matter and radiation of our present universe were packed together in the primeval

fireball -- an extremely hot dense state from which the universe rapidly expanded. The

Big Bang was the start of time and space. The matter and radiation of that early stage

rapidly expanded and cooled. Several million years later, it condensed into galaxies. The

universe has continued to expand, and the galaxies have continued moving away from

each other ever since.

Today the universe is still expanding, as astronomers have


The Steady State model says that the universe does not evolve or change in time. There

was no beginning in the past, nor will there be change in the future. This model assumes

the perfect cosmological principle. This principle says that the universe is the same

everywhere on the large scale, at all times. It maintains the same average density of

matter forever.

There are observational evidences found that can prove the Big Bang model is more

reasonable than the Steady State model. First, the redshifts of distant galaxies. Redshift

is a Doppler effect which states that if a galaxy is moving away, the spectral line of that

galaxy observed will have a shift to the red end. The faster the galaxy moves,