Many ways can be answered this question. I want to address this little differently. Cave man: What is that in sky? Cave man 2: Wow! I am scared, what is that? Cave man: Let's get back to home to my girl Cave woman: Look! Look! Must be magic. When I scratched this stone to other stone, some kind of light is coming out Cave man: Must be God's light Caveman 2: Bless us God