Why is the Pope petting Stephen Hawking?

Because he is the motherfucking pope and he can do what ever the fuck he wants because he is the leader of a fucking religion. Maybe the religious сука likes pettin' people. I sure do.
I am not a Christian.

He's obviously trying to turn Stephen Hawking away from the world of science!

Pope: Shh, Hawking, shhh. I'm not trying to hurt you. That's it. Good boy. Shh.

the pope isnt petting him... he is blessing him... it would be akward if the pope wa petting him...

OBVIOUSLY the Pope has realized that Stephen Hawking is a genius even if he does deny God and he's trying to absorb his neurons.

He's just blessing him.