is it possible to understand an aspect of chess more then carlsen

like is it possible for one of you guys to maybe know more about openings, or certain posistions then magnus?

Yes.

Now you can sleep at night.

so you could beat him if you got into those posistions against him

Who is Carlsen?

Of course. I bet Magnus doesn't know what the Daeth Opining is.

+1

Has there ever been a world champion that knew more than his successors? Ask this question in 30 years time .

Well there will always be someone better to surpass the best given enough time.  And it is possible for one of us to know some part of the game better than him, no one will ever (hopefully) have perfect knowledge of the game.  

Of course, I am sure I understand better the agony of managing to stalemate my opponent when I am up a Queen and a Rook!

You can know more than him but that doesn't mean you will be able to beat him in a game. While you understand more than him, he knows how to implement what he understands and think ahead/strategize with the concepts he knows.