Don't be afraid. It's OK. Calm yourselves. No need to descend into apoplectic rage because there are atheists in the world.
The framework of how you view your lives is thousands of years old developed by 'mystics' and 'prophets' who had no insight into our enlightened age of reason and science. People who may very well have needed religion or faith to make sense of the world because they lacked the science to do so. And that was acceptable for them, but surely not for you?
The Muslims know the Jews are wrong, who know the Christians are totally off the mark, who know that the Mormons are just plain crazy, but not as crazy as those Scientology people.
Once the rage has passed, try and think outside the box of your faith for a moment, which is a difficult thing to do objectively I will concede.
It is so bright on this side you will wonder why you ever actively tried to live in the dark.