Big Bang

4 Pages 1120 Words

The mystery of the beginning of our universe has puzzled mankind since the dawn of time. This mystery is especially relevant to astronomers, who construct hypotheses called cosmological models to try to find the answer to this ancient question. This paper will focus on two of these models: The Big Bang Theory and The Steady State Model. The Big Bang model postulates that about fifteen to twenty billion years ago, the universe violently exploded.
Scientist believe that before the Big Bang, all of the matter and radiation of our present universe was packed together in a primeval fireball. This fireball was in an extremely hot dense state. From this the universe rapidly expanded.1 As this expanding matter 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 observed.
The Steady State model states that the universe does not evolve or change in time, meaning there was no beginning in the past, nor will there be change in the future. This model assumes the perfect cosmological principle. This principle states that the universe is the same everywhere on the large scale; at all times.2 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 including, 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 the more shifts it has. If the galaxy is moving closer, the spectral line will show a blue shift. If the galaxy is not moving, there is no shift at all. However, as astronomers observed, the more distant a galaxy is from Earth, the more redshift it shows on the spectru...