User blog:Spartian300/Why couldn't Captain America lift Thor's hammer?

I'm sure we have all seen the first clip for Avengers: Age of Ultron. Now, basically, everyone is taking turns trying to lift Thor's hammer. Tony and James Rhodes fail, Natasha refuses, but Cap actually makes it budge. Why? We can see on Thor's face that he is surprised that Cap made it BUDGE. So, why could Captain America not lift it? What happened?