Recently one of my former MCCC philosophy students wrote and asked me a couple of questions. I thought I'd post my response here.
Hi ____ -
You asked: do I believe other life forms exist on other planets? Here's my position, which has nothing to do with belief in God or Christianity.
I am currently a "rare earth theorist." What does that mean? It's the position of astrophysicists Ward and Brownlee (University of Washington) as expressed in their book Rare Earth, as well as the position of Guillermo Gonzalez (Iowa State) in his book The Privileged Planet. Which is: definitely, most likely, "life" exists outside of earth, but such life is, most probably, no more than a flatworm. Probably, because of the vast improbability of all the needed rare earth factors coming together, there's no other intelligent life in the universe, outside of earth.
Note: This is a purely scientific theory, not a religious idea. For me, as both a theist and a Christian, whether or not there is intelligent life outside of earth has no effect on my philosophical and theological views.
Coming at this in another way, I see no biblical or theological reason to argue for or against life outside of earth.
Second, you ask: do I believe dinosaurs used to exist? Yes. Right now, my position would be similar to that of astronomer Hugh Ross. I do not see that the existence of dinosaurs at all negatively affects my belief in God and my Christian faith. For example, the word for "day" in the book of Genesis is the Hebrew word yom. "Yom" can be translated as "24-hour-period" or, e.g., "period of time" or "epoch" (like, "in the day of Abraham Lincoln). I choose to translate "yom," as used in the Genesis creation account, as "period of time." See Ross's website here for some points of view that interest me re. such discussions.