On the subject of the universe, a most persistent question has been: How was it created? Many once believed that the cosmos had no beginning or end and was truly infinite. The Big Bang theory, however, ended infiniteness, forcing the heavens to take on properties that include a history and a potential end.

About 14 billion years ago a tremendous explosion, called the Big Bang, started the expansion of the universe. At the point of the event all of the matter and energy of space was contained at one point. What existed previously is completely unknown and is a matter of pure speculation. The occurrence was not a conventional explosion but rather an event that filled space with all of the particles of the embryonic universe rushing away from each other. The Big Bang actually consisted of an explosion of space within itself, unlike an explosion of a bomb were fragments are thrown outward. The galaxies were not all clumped together, but rather the Big Bang laid the foundations for the universe.

[Students of the Big Bang soon realize that the theory is one of the murkiest aspects of science. All the great astronomers of the world agree that a cataclysmic event occurred about 14 billion years ago but when they try to explain what may have happened they run into some difficulty. Its kind of like the answer one gets to the question, "Where was Joe when he jumped off the bridge?" It the answer is, "He was in the air," then the retort is, "No. That was after he jumped." If the response is, "He was on the bridge." Then the come-back is, "No. That was before he jumped." …And so it goes. No one can explain what happened the instant before, during, or after the Big Bang and no one has a comprehensible idea of what may have existed before the Bang.]

Credit for the origin of the Big Bang theory belongs to Edwin Hubble. He made the observation that the universe is continuously expanding. He also discovered that a galaxy's velocity is proportional to its distance. Galaxies that are twice as far from us, move twice as fast. A consequence is that the universe is expanding in every direction. This observation means that it has taken every galaxy the same amount of time to move from a common starting point to its current position. Just as the Big Bang provided for the foundation of the universe, Hubble's observations provided for the foundation of the Big Bang theory.

Since the Big Bang, the universe has been continuously expanding and, thus, there has been more and more distance between clusters of galaxies. This phenomenon of galaxies moving farther away from each other is known as the red shift. As light from distant galaxies approach earth there is an increase of space between earth and the galaxy, which leads to wavelengths being stretched.

In addition to the understanding of the velocity of galaxies emanating from a single point, there is further evidence for the Big Bang. In 1964, two astronomers, Arno Penzias and Robert Wilson, in an attempt to detect microwaves from outer space, inadvertently discovered a noise of extraterrestrial origin. The noise did not seem to emanate from one location but instead; it came from all directions at once. It became obvious that what they heard was radiation from the farthest reaches of the universe, which had been left over from the Big Bang. This discovery of the radioactive aftermath of the initial explosion lent much credence to the Big Bang theory.

Even more recently, NASA's COBE satellite was able to detect cosmic microwaves emanating from the outer reaches of the universe. These microwaves were remarkably uniform which illustrated the homogeneity of the early stages of the universe. However, the satellite also discovered that as the universe began to cool and was still expanding, small fluctuations began to exist due to temperature differences. These fluctuations verified prior calculations of the possible cooling and development of the universe just fractions of a second after its creation. These fluctuations in the universe provided a more detailed description of the first moments after the Big Bang. They also helped to tell the story of the formation of galaxies.

The Big Bang theory provides a viable solution to one of the most pressing questions of all time. It is important to understand, however, that the theory itself is constantly being revised. As more observations are made and more research conducted, the Big Bang theory becomes more complete and our knowledge of the origins of the universe more substantial.