First I would like to apalogize if this is not right thread for my question, but I am not sure where to put it. If I understand it right, vaccum is actually full of virtual particles and antiparticles popping into existence and anihilating again and that always particle and antiparticle are created so it is zero sum game. However those particles (electron, positron) also should have some gravity, right? So such event would temproarily increase gravity in that area which would affect other mass, but then they would have to be real particles, because they interact. And also vacuum should than show some gravity. Am I missing something or virtual particles have no gravity although they have mass?