Modern theological scholars would say that the major difference between the creation story in Genesis and that in modern science is one of genre. Like many oral-derived works, such as the Babylonian creation stories and Hesiod's Theogony, Genesis was first composed and passed down orally as a narrative explanation of the state of the world in relation to the divine. These stories were not understood literally, in the sense in which 21st centuries theories and understood as "what actually happened"; instead they were illustrations of the nature and power of the gods. It was really in the Renaissance, with the advent of early modern science, that certain readers (mainly Protestant) began to ignore the allegorical levels of the Bible and try to read Genesis as purely literal and scientific (e.g. Bishop Ussher using it to calculate the age of the world). Thus the conflict between "young earth" Creationists and modern science is really due to people trying to apply simplistic scientific and literal readings to complex and partially allegorical texts. The Big Bang is really a simple theory in a certain way, simply stating "What happened" but Genesis is concerned with why things happened and what religious acts and beliefs that entails.