I believe the Bible but I believe that God was speaking to a very primitive group of people. Just like speaking to a child, you have to use easy examples to teach a lesson, you have to bring it down to their level. Therefore, the Bible is a group of parables or stories. Just like the fig tree that did not bear fruit, Jesus could have made figs as easy as he made the loaves and fishes but there is a lesson there.
I think, in my humble opinion, that when God left the Bible he never said "This is all that there is and there is no more." He did not feel the need to explain everything to us. The bible is more than we can ever comprehend in a lifetime but I don't think he got into the fine details.
For example, in Genesis when Cain killed Abel and was banned from Eden his first concern was that "The people out there will kill me." God said that he would put a mark on him so that they would not kill him.
Who were these other people if Adam and Eve were the first people and Cain and Abel were the first sons? God gives us lessons that small minds can learn. Jesus said "I have sheep in other flocks."
When you look into the night sky at the stars and consider that each one of those stars is a sun, just like ours with planets orbiting, and then consider the endless trillions of stars that exist that are beyond our vision without end, how can we think that we are the only ones?
Is God not big enough to manage other star systems, planets and people? I've never seen a UFO either but the vastness of the universe suggests that life may very well exist out there and that does not conflict with my Christianity.