A force field is an energy field with the ability to prevent particles, radiation, or physical objects from passing through it. A force field will often allow the passage of other substances, such as light, making the force field partially or completely invisible. These fields have been a fixture of science fiction in film, literature, and comics since the early 20th century. Real-life scientific constructs have some of the properties of fictitious force fields.
The concept originated with the science fiction writers of early 20th-century pulp magazines like Amazing Stories, Weird Tales, and Doc Savage. Films and television shows such as Star Trek and Star Wars used them as dramatic devices during starship battles. In later years, Star Trek also applied the device for practical matters, such as an airlock between the ship’s atmosphere and the vacuum of space. In most cases, the force field was a handy way to solve story problems; its actual mechanics were rarely discussed.
When science fiction and superhero comics came to prominence in the 1950s and 1960s, the concept found even greater use. Numerous characters, both good and evil, could create force fields, either through the use of high-tech devices or as an innate ability. Prime among the latter was the Invisible Woman, a member of the Fantastic Four superhero team. Soon after the character’s creation in 1961, writer Stan Lee realized she needed an offensive weapon to accentuate her invisibility. Again, only a few exceptionally creative writers attempted to explain the actual processes used to create comic book force fields.
Scientific research and experimentation have created devices that can duplicate the effects of the field. Plasma, an ionized gas, has been proposed as lightweight radiation shielding for long-range spacecraft. An electrically charged mesh would have to surround the craft for this kind of force field to be effective. The plasma window uses a magnetic field to create a plasma-filled area that has many classic properties of a force field, including the separation of vacuum from atmosphere. Its main disadvantage is that tremendous energy is required to create even a small plasma window.
In many ways, the earth’s magnetic field, a naturally occurring phenomenon, is a kind of force field. Created by the motion of liquid iron in the planet’s core, the magnetic field is an invisible spheroid extending thousands of miles around the Earth. It shields the planet from solar radiation that could otherwise strip the Earth of its atmosphere and prove lethal to living beings. Electrons in motion in the magnetic field deflect this radiation, itself made of electrons emitted from the sun.