"It's arrogant for atheists to claim there is no God but then go on to claim there are aliens."
Just as its arrogant for those of a religious bent to claim that there is a god and hence no aliens.
"There is absolutely no evidence for aliens."
Ditto God.
However, there is simple statistics. With there being 1,000,000,000,000,000,000,000,000 stars kicking around it's blisteringly, mind-numbingly arrogant to suggest that there *isn't* life elsewhere.
"There is absolutely no evidence for aliens. They are not mentioned in the bible"
Wow.
Just wow.
Nor are microbes, gamma rays, cheesecake, or a correct value for Pi. Do they not exist?
"and even the science books admit no aliens have been found."
'The Science Books'? Which ones, exactly? Is there a definitive list?
They 'admit' it, because that's the truth. Are you inferring that they would rather lie? I don't think 'science' means what you think it means.
"They are made up creatures like zombies and seahorses."
I hate to break this to you, but seahorses are a real thing.
http://en.wikipedia.org/wiki/Seahorse
"All the telescopes in the world have been spinning round frantically looking for aliens"
No they haven't. They've only been looking for planets outside our own solar system for 5ish years. How do you think we can 'see' aliens through a telescope?
"NASA supposedly landed men on the moon"
They did. That's how they put a mirror there that bounces lasers back, so we can measure how far away it is. Or did you think that they magiced up there?
"if so they must have looked real hard in craters and suchlike when they were there but still NO aliens. So when are they going to get a clue and admit defeat?"
So... we didn't find an alien on our moon, so there's not one in the infinite reaches of space?
Is there an elephant in your kitchen? Then by your logic, there are no elephants.
"It's the 21st century boys, it's high time to grow up and stop believing in little green men."
It is indeed. High time you grew up and stopped believing that anything that's not in the Bible doesn't exist.