This is a very good question. I wish I had a simple answer. Of course the idea that we were somehow influenced by extraterrestrials is silly. I think the problem you are having is that some of our beliefs as Christians are laughed at as silly by well educated intellectual people. Naturally, when you call someone’s belief in ancient astronauts or extraterrestrial interventions silly, you are forced to ask if you believe silly things as well. You SHOULD ask this question. It is part of being intellectually honest. I assume you believe that Jesus was raised from the dead. I assume that you believe that Moses really did lead the people of Israel out of Egypt and that you believe Jesus will come back, bringing an end to the earth as we know it. All these things are thought of as silly by many people.
This brings up the question of how we can separate a belief is rational/reasonable from one which is not rational. To get at this question one must ask good questions. Let us use the resurrection as an example. We cannot blame some who do not know the context of the life of Jesus for thinking this belief to be "silly." Yet, when we look at the facts, we discover that perhaps this belief is not silly at all. Here are some questions to ask. What are the facts? What or who is the source of the facts? How reliable is the source? What are the alternative explanations? How likely are the alternative explanations? What is the context of the claim? What assumptions must be made to reach each possible conclusion? Are these assumptions reasonable? I believe if one carefully analyzes the question of the resurrection, the most reasonable explanation is that Jesus did indeed raise from the dead. The facts (empty tomb, hundreds of eye witnesses, soldiers at the tomb, soldier’s testimony that Jesus was dead…) lead in this direction. The sources are of the absolutely highest reliability (considering the character of Jesus and future acts of the apostles). The alternative explanations (body stolen, did not really die, etc.) seem more believable at first glance, but upon careful study and thought they are simply not reasonable.
If you apply this type of analysis to claims such as astrology or ghost sightings or extraterrestrial source for humans, these claims are either not a reasonable explanation or perhaps even downright silly. I believe your faith in Jesus and in the inspiration of the Bible is reasonable, but al of us should subject that faith to reasonable scrutiny. Do not worry, your faith will be strengthened, not weakened by such an analysis.
John Oakes, PhD