Of course, a few minutes on Google, or reading a book on Big Bang cosmology would dispel that cherished myth and I have dealt with this several times in this blog, here and here and here, so I'm not going to rehearse the science yet again.
Instead, let's look at what Christians and Muslims believe.
Um... well, strangely enough, they believe the universe was magically created out of nothing.
How odd that they believe the very thing they wrongly ridicule Atheists for believing. How odd that the infantile parody they accuse Atheists of believing is the very thing they believe themselves.
Anyone would think Creationists no more know what they believe than they know what Atheists believe.
So, Christians and Muslims, instead of showing your ignorance by being wrong about Atheism, how about showing us your knowledge by answering the following simple question:
How did your god created everything out of nothing?
If it didn't create everything out of nothing, who or what created the stuff it used and out of what?