The Big Bang Theory was first proposed by Georges Lemaitre in 1931. Later, others helped popularize the idea. He theorized that 14.5 billion years ago (this age has been increased and decreased over the years), a ball of condensed energy called a singularity exploded, and over the course of millions of years, the contents of that singularity spread out into the universe, forming stars, planets and solar systems. There are many problems with this theory. The following article explains the Big Bang Theory and its technical problems more in depth: http://www.answersingenesis.org/articles/ee2/big-bang
A growing group of scientists have written a letter to the scientific community pointing out the flaws: www.cosmologystatement.org. (Note: That link takes you to another site where the letter has moved. It is no longer located at the address you click on, but another website has adopted it.
The Bible is a collection of 66 individual books. It includes different writings such as laws, historical narratives, biographies, poetry, prophecies, and letters. There were 40 authors who wrote the different books. The Bible records the beginning of Earth’s history, and the very first sentence is “In the beginning, God created the heavens and the Earth” (Genesis 1:1). Before this, there was no history, thus the term “prehistory” is unnecessary. The Bible gives us an understanding of biology (created kinds), anthropology (the dispersal and creation of people groups after the tower of Babel), linguistics (tower of Babel), astronomy (planets and stars) and geology (the results of the catastrophic flood). The Bible is not a science textbook—those have to be updated every few years.