A lot of Christians make the mistake of rejecting science too hastily. As Einstein said, "Religion without science is blind." Christians should not fear science, because it can reveal much about the world in which we live. It does not have to contradict the Bible, because as Einstein also said, "Science without religion is dead." This is particularly true in the area of creation. More and more scientists and Christians are beginning to see their their ideas about creation are not necessarily mutually exclusive.
Rather than asking whether they universe was created by God or by the Big Bang, we should ask if God used the Big Bang to create the universe. Even talking about the Big Bang seems taboo to many Christians, but it very well could have been the mechanism that God used to create the universe. We will have to debate each other over the details, but there is no basic contradiction between Biblical creation and the theory of the Big Bang. Christians should not scoff at the evidence for an expanding universe because there is so much of it that virtually everyone in the scientific community agrees that the universe is expanding. There are two main pieces of evidence to support this theory.
First, there is the fact that distant galaxies seem to be getting further apart. Think of the universe as an inflatable ballon. As the universe expands, two points drawn on the surface of the ballon will get further apart. We see the same phenomena in the universe. Second, we see that light in distant parts of the universe has a doppler effect. The same way that a car sounds different when it passes you than it did when it was moving towards you, the movement of galaxies away from the core of the universe shifts the color of those stars to a different wavelength. This movement produces different colored light than we would expect to find if the universe was not expanding. For this an a variety of other reasons, scientists are almost certain that the universe is expanding away from a central core.
If the universe is expanding, than it must have been much smaller at one point. Tracing the history of the universe as far back as we can and by applying our most advanced models of cosmology, we have determined that the universe was once contained in an infinitely small, infinitely massive space. Something happened to cause this massive material to explode and expand outward and it has been expanding ever since. While expanding, some of that material became what we know as the sun, moon, stars, and planets.
Christians need to realize that the Big Bang allows for the possibility of a Creator. In fact, many scientists believe that it necessitates a Creator because the laws of science as we know them break down in the first moments of the birth of the universe. Science cannot explain everything. Also, if the Big Bang is indeed a correct theory of the creation of the universe, than it implies that the universe was, at some point, created. The logical question is who created it? Realizing that only an infinite God could create something infinitely small and infinitely massive and use it to create the universe as we know it.
Obviously, those who believe that God created the universe by initiating the Big Bang may have disagreements with those who take the Genesis account of creation literally. Those who take the Genesis account literally, however, need to realize that the Big Bang is not necessarily an atheistic doctrine. In fact, recognizing that the universe had a beginning is the first step to acknowledging that someone had to create it. Scientists may one day disprove the Big Bang, but until then, it would be more constructive for Christians to have a dialogue with scientists. Christians will not get anywhere with scientists and others if they refuse to even acknowledge the possibility of a Creator induced Big Bang.
Here is what I will say, Creation happened because God spoke and only because God is Almighty and therefore has that power, pure and simple. God Spoke and Bang it Happened, that is not theory that my dear friend is stone cold Biblical Fact. How there can be atheists in the world is far beyond my comprehension.