In fictional works, a force field, sometimes known as an energy shield, force shield, or deflector shield is a barrier made up of energy or particles to protect a person, area or object from attacks or intrusions. This fictional technology is created as a field of energy without mass that acts as a wall, so that objects affected by the particular force relating to the field are unable to pass through the field and reach the other side. It is a concept popular in science fiction and fantasy works. Scientific research into real energy shields is ongoing, primarily to protect against radiation.