This is a very odd defense, nonetheless it's still legit. This one is short and sweet.
Ask an atheist this, "Do you know everything?" They'll say something like, "No, of course not." Then ask, "Do you know maybe half of everything?"
You see, scientists today estimated about 70,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000 known stars.
We don't know about the ones that we don't know about.
This argument isn't proof for God, I know. But it is an effective way to let the atheist know that they don't know everything, so they shouldn't judge like they do.