The other day I was talking to a very Christian guy who felt the whole Pluto thing was a complete and utter waste of time. He said that the Bible mentioned no life in outer space, and it takes place entirely on earth, which means that none of that stuff is of any consequence.
I pointed out that I'm a Christian myself, and that I personally don't think there's any life anywhere else in the solar system, but that's not the point. The point is (Quoting the Bible) that "The heavens declare the glory of God," and that in studying them, we learn more about God's glory, therefore that's got to be of some value, right?
I also pointed out that in Genesis, God specifically gives man dominion of the world. "World" and "Universe" are the same word in ancient Hebrew. Ergo, we're in charge of space.
I also pointed out that since we were commanded to be fruitful and multiply, and we're running out of easily-available space and resources, the presence of a bunch of other planets and moons at arm's length would obviously be useful. We can be fruitful and multiply in other places as well.
Finally I pointed out that his logic was flawed on the "The Bible takes place entirely on earth, therefore nothing else matters" comment. 90% of the Bible takes place in Israel, with most of the rest taking place in Babylon, Egypt, Asia Minor, and like a paragraph in Rome. If *only* the location of the events of the Bible are important, then the Americas and Australia are of no consequence whatsoever, and should never have been colonized. They're not mentioned in the Bible, after all.
He then switched to "It's a waste of money that could be better spent on earth," and rather than argue I just said, "The government is going to waste your money no matter where they spend it."
I'm a Christian and my dad was a NASA engineer, and I've met this kind of resistance my whole life. I don't hate these people, I think they're just a little ignorant and I think it is the duty of every scientifically literate Christian (There are hundreds of millions of us) to educate our scientifically illiterate brethren (Who doubtless outnumber us). It is not sinful to go into space.