Among the many unsupportable things you've asserted, this may be the most ridiculous.
A hundred years ago, nobody could name a black hole. Did they exist a hundred years ago? Certainly. Not being able to name something doesn't mean it doesn't exist. Sheesh.
You can't tell me the source of morals other than, "there could be another source..." - a pie in the sky zero evidence hope against hope leap of faith - and you call my assertion ridiculous!? Yeah right.
A hundred years ago, nobody could name a black hole. Did they exist a hundred years ago? Certainly. Not being able to name something doesn't mean it doesn't exist. Sheesh.
You have not one iota of evidence for a source of morality other than God - in fact, you are not even able to name a possibile source from your imagination! You can't even imagine it! Come on now, I can at least imagine a pink unicorn or the tooth fairy, but you can't even do that! Your argument cannot be more silly than it is.