In speculative fiction, a force field, sometimes known as an energy shield, force shield, energy bubble, or deflector shield, is a barrier produced by something like energy, negative energy, dark energy, electromagnetic fields, gravitational fields, electric fields, quantum fields, plasma, particles, radiation, solid light, or pure force. It protects a person, area, or object from attacks or intrusions, or even deflects energy attacks back at the attacker. This fictional technology is created as a field of energy without matter 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, instead being deflected or destroyed. Actual research in the 21st century has looked into the potential to deflect radiation or cosmic rays, as well as more extensive shielding.
This concept has become a staple of many science-fiction works, so much so that authors frequently do not even bother to explain or justify them to their readers, treating them almost as established fact and attributing whatever capabilities the plot requires. The ability to create force fields has become a frequent superpower in superhero media.
History
The concept of a force field goes back at least as far as early 20th century. The Encyclopedia of Science Fiction suggests that the first use of the term in science fiction was in 1931, in Spacehounds of IPC by E.E. 'Doc' Smith.
An early precursor of what is now called "force field" may be found in William Hope Hodgson's The Night Land (1912), where the Last Redoubt, the fortress of the remnants of a far-future humanity, is kept safe by "The Air Clog" generated by the burning "Earth-Current".
In Isaac Asimov's Foundation universe, personal shields have been developed by scientists specializing in the miniaturization of planet-based shields. As they are primarily used by Foundation Traders, most other inhabitants of the Galactic Empire do not know about this technology. In an unrelated short story Breeds There a Man...? by Asimov, scientists are working on a force field ("energy so channelled as to create a wall of matter-less inertia"), capable of protecting the population in case of a nuclear war. The force field demonstrated in the end is a solid hemisphere, apparently completely opaque and reflective from both sides. Asimov explores the force field concept again in the short story Not Final!.
The concept of force fields as a defensive measure from enemy attack or as a form of attack can be regularly found in modern video games as well as in film, such as in The War of the Worlds (1953, George Pál) and Independence Day.
The ability to create a force field has been a common superpower in comic books and associated media. While only a few characters have the explicit ability to create force fields (for example, the Invisible Woman of the Fantastic Four and Violet Parr from The Incredibles), it has been emulated via other powers, such as Green Lantern's energy constructs, Jean Grey's telekinesis, and Magneto's manipulation of electromagnetic fields. Apart from this, its importance is also highlighted in Dr. Michio Kaku's books (such as Physics of the Impossible).
Fiction
Science fiction and fantasy avenues suggest a number of potential uses of force fields:
A barrier allowing workers to function in areas exposed to the vacuum of space. The atmosphere inside would be habitable by humans, while at the same time allowing permissible objects to pass through the barrier A walkable surface between two points without the necessity of building a bridge. An emergency quarantine area to service those afflicted by harmful biological or chemical agents A fire extinguisher where oxygen is exhausted by the use of a space confined by a force field thereby starving the fire As a shield to protect against damage from natural forces or an enemy attack As a deflector to allow fast spaceships to traverse space without colliding with small particles or objects. A temporary habitable space in an area otherwise unsuitable for sustaining life As a security apparatus used to confine or contain a captive