Sam Minewire wrote:
> There are probably thousands of alien cultures in outer
> space, but what if they don't believe in our GOD.
> 
> Can we destroy them in the name of GOD?

No, there would be no ethical basis for destroying them.  That's as 
close as science comes to this question.

> Are they sinners?

It would depend on their actions.  Technically, if they break a code, it 
doesn't matter who they are, they transgress the code.  So, each 
religion could validly call them sinners to the degree that they break 
the code.  Just as each human government could call them criminals for 
breaking their codes.

> Can we burn them at the stake for not believing in GOD?

I think burning at the stake is not a proper punishment, according to 
the Jewish or Christian codes.  I don't know of any religious code where 
burning at the stake is a proscribed method for dealing with sinners.