An image of the very early universe from the Planck Satellite has been released by the European Space Agency. This is the most precise image obtained so far of what is known as the cosmic microwave background radiation, which is found throughout the universe. The results raise questions for some aspects of the standard model of cosmology, but in general provides confirmation of the big bang. In fact, the results are claimed to show that the universe is slightly older than previously thought, with the big bang dated at 13.82 billion years.
When I was a teenager, scientific findings of this kind presented a challenge to my faith. Didn’t the big bang remove the need for God? I wanted to take both belief in God and science seriously, but a perceived tension between the two made it difficult. Now, I’m much more inclined to think that science and belief in God are quite compatible and that there is a much greater tension between atheism and science. Far from removing the need for God, the big bang presents a real challenge for atheism. If the entire physical universe had a beginning, how did that come about? The only options seem to be that it came into existence uncaused out of nothing or that it had a non-physical cause.
Some physicists have claimed to offer a scientific explanation of how the universe could have come into existence out of nothing, but this involves a slight-of-hand with the term ‘nothing’. The idea that the universe popped into existence uncaused out of literally nothing is very difficult to take seriously. So it seems to me that a non-physical cause is a much more plausible direction to go. Granted, it’s not immediately obvious that the non-physical cause must be equated with God, but such a cause is much more consistent with theism than with atheism. And if the big bang represents the beginning of space and time, this seems highly consistent with theism.
One way to try to reconcile atheism with the big bang would be to say that the big bang does not represent the beginning of the entire physical universe, but just our part of it. Perhaps our universe emerged out of a pre-existing universe. If so, this would seem to avoid the need for an absolute beginning. It’s worth noting that even if there were a pre-existing universe, there might be good reasons for thinking that it had a beginning too. More significantly, is there any evidence for a pre-existing universe? There’s plenty of speculation, but that’s about all. That’s not to say that there could never be any such evidence. Perhaps analysis of the Planck data could even provide some, but on current evidence (and that’s all we have to go on) there doesn’t seem to be any convincing reason to believe in a pre-existing universe.
So perhaps there are some ways to reconcile atheism and big bang cosmology, but given our present scientific knowledge about the early universe, the problems are much greater for atheism than for theism.
 See David Albert’s review of Lawrence Krauss’s ‘A Universe from Nothing’ available at: http://www.nytimes.com/2012/03/25/books/review/a-universe-from-nothing-by-lawrence-m-krauss.html