In science fiction they go by a variety of names — shields, screens and deflectors being among the most popular — while the expression "force field" is more often used to describe the underlying principle, rather than specific defensive installations protecting spaceships, cities or entire planets in a science fiction story.

As science writer Ella Alderson at Medium notes, force field defenses are so well established in science fiction that authors and scriptwriters hardly need to explain them. Readers and viewers are so up to speed on what they are that it's generally enough for the captain in the scene to order "Full deflectors!" or the chief engineer to warn, "The screens canna take much more!"

This is good news for the creative community, because unlike many science fiction technologies, force field defenses have not yet made their debut in the real world, and the science around them is uncertain enough that an explanation would be tough to write, even in fiction. But are they possible off the screen and page?

Fields All Around Us

On the level of pure science, the answer is a resounding Yes. Not only are they possible, but they are actually all around us. If you go out and buy one of those little horseshoe magnets, you can have your own force field generator that will lift up a steel needle, overcoming another force field, Earth's gravity. Alas, what it won't do is stop a phaser beam, or even an old-fashioned bullet.

The four basic forces that govern our universe — gravity, electromagnetism, and "strong" and "weak" nuclear forces — are all associated with fields that could certainly be called force fields, and some of these can provide protective shielding. Earth's magnetic field protects us all (including all present-day astronauts) from dangerous high-energy solar and cosmic particle radiation.

Indeed, as USRA reports, NASA has seriously examined electromagnetic shielding for prolonged deep space missions as an alternative to massive physical shielding. Unfortunately, at our current state of technology, the required field generator would be even heavier than the shielding it would replace, so a lot of development work has to be done before force field protection against deep space radiation becomes viable.

On the bright side, a lot of development work means exactly that: work to be done, which is quite different from impossible.

How To Stop a Shockwave

There are ongoing projects aimed at bringing us closer to classic science fiction-style force field defenses. One defense contractor has even patented a technology to protect vehicles from destructive shockwaves produced by explosions. A combination of electric arcs and lasers would be used to flash a wall of air into plasma — atoms so superheated that nuclei and electrons go their separate ways, making the plasma controllable by magnetic fields.

Such plasma can deflect and therefore effectively absorb an oncoming shockwave, protecting the vehicle. One limitation is that while plasma readily deflects shockwaves, physical objects (such as shells or missiles) can pass through the plasma wall unimpeded, so other defenses would be required against these threats.

As an additional caution, Mic.com notes that technology companies patent many ideas to protect their intellectual property, but not all of them end up being developed.

Meanwhile, at TheDrive.com, Brett Tingley describes yet another ongoing project by the Air Force that uses ultra-high-power lasers to produce a force field capable of destroying or disabling incoming warheads or other weapons. The article notes that existing (experimental) laser defenses can actually knock out drones in tests by enveloping them in brief, localized force fields.

According to Jeremy Murray-Krezan of the Air Force Research Laboratory, directed energy (DE) "is uniquely suited for an area of growing importance, nondestructive but damaging, disruptive, and denial of operations." Modern combat, it seems, is already a more complex environment than what we typically see in science fiction.

Are Force Fields Possible?

We are still a long way from the force field defenses that are popular in science fiction — protection that functions like the armor on a World War era battleship, stopping incoming attacks without needing to be aimed at specific threats. Our current understanding of physics suggests that such preclusive defense against modern weapons would be difficult to achieve without dramatic technological advances that we cannot yet confidently foresee.

Still, active research is opening new possibilities for defenses and protection, suggesting that if force fields do become part of our defensive arsenal, they may take a different form from the shields and screens made popular in science fiction.

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