Why cannot virtual particles in the vacuum be directly detected? Experiments have shown the Casimir Effect that supports the idea of virtual particles does exist. But can we also detect the presence of virtual particles directly in the vacuum? The most common virtual particle to form is photon because it has zero static mass (the havier the particle is, the shorter it exists). Therefore, once it has formed, is there a way how to detect its existence before it dissapears again? If there is not, why?