Invincible force fields are a longtime staple of science fiction, but can they exist in real life? Maybe, but not in the way you might imagine.
Second to faster-than-light engines – and only marginally so – protective force fields are one of the most significant science fiction conventions. Ever since they first appeared in E.E. “Doc” Smith’s novels in the 1930s, force fields have been used in countless movies, television shows, books, and comics. There’s a good reason for this, as these invisible paper-thin barriers are practically indestructible and can stop or repel everything from bullets to laser beams.
But how close are these imaginary shields to existing today? As it turns out, scientists may be closer to creating force fields than once thought possible.
What is a Force Field?
A force field would have to be able to block two things simultaneously: matter (bullets, missiles, rocks, etc.) and radiation (lasers). But perhaps the word “field” is a bit misleading. There are currently four types of known fields in the universe: gravity, electromagnetism, and strong and weak nuclear fields. None of them could work by themselves to produce the kind of protection sci-fi proposes on Star Trek, Star Wars, and a multitude of other films.
Gravity is the opposite of what a force field is supposed to be. It’s an attractive force instead of a repelling one that’s spread out over great distances. The field also happens to be pretty weak, since you defeat an entire planet’s worth of gravitational force every time you pick something up.
Electromagnetism works better since it is a strong repelling force. But it’s difficult to shape a magnetic field into a paper-thin barrier, and it’s absolutely useless against insulative materials like plastic and rubber. Weak-conductive metals like lead, which most bullets are made from, would also have little trouble passing through an electromagnetic field.
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That leaves strong and weak nuclear fields. Weak nuclear fields are related to radioactive decay. They keep the planet’s core hot and are responsible for continental drift and volcanic eruptions. Meanwhile, strong fields hold the nuclei of atoms together and are what powers our sun and stars. However, neither of these forces cover any great distance (only a few nuclei), and the only way we’ve been able to manipulate these forces is by using them to collide subatomic particles and detonate nuclear explosions.
So, unless we discover a fifth type, fields alone won’t be enough to protect a vehicle or person. But there’s progress being made to create a workable type of protective energy barrier.
Real-Life Force Fields
In 2002 the UK defense science and technology division began development for a supercapacitor for its tanks. They would store an enormous electrical charge to stop incoming RPGs (Rocket Propelled Grenades), which releases molten copper into the tanks hull. Molten copper can melt through over a foot of solid steel, and no tank can afford to have armor thick enough to stop it.
In essence, these supercapacitors would allow tanks to carry lighter armor by turning it into a giant battery. Penetrating its outer shell with copper would complete the supercapacitor’s circuit, causing its electrical energy to release and create a powerful electromagnetic field that vaporizes the copper before it burns through the tank. It’s still in the developmental stages, but there’s already work underway to create a means of repelling projectiles before they hit the tank.
However, the technology comes with significant limitations. For instance, the EM field only lasts a fraction of a second, which is a far cry from the sustained barriers we see in science fiction. Also, this shield is designed specifically to counter RPGs and would offer no protection against bullets and lasers, which would still be handled by traditional armor.
The good news is that sci-fi soldiers don’t have to worry too much about laser weapons on Earth. Although tactical high energy lasers (THEL) such as the US/Israeli Demonstrator have been able to shoot down artillery shells, the technology has quite a few fundamental problems right now.
Mainly, they’re big (the Demonstrator is about the size of six city buses), require a ton of energy, and are relatively easy to block. That’s because lasers are focused beams of light. Therefore, anything that can block, diffuse, reflect, or refract light can stop it. Rain has all those properties, and it can successfully block a military grade laser with 100 percent effectiveness. A nice shiny mirror would work, too.
But fighting in space is an entirely different story. Lasers are potentially devastating weapons in space, which is why it will be important to defend against them.
To this end, physics students at the University of Leicester proposed using plasma, a superhot electrically charged gas, as a shield. This theory has been proven to work on a large scale, as the Earth’s ionosphere is full of plasma that blocks low-frequency radio waves while protecting against high-energy protons and electrons. The trick would be to make a dense plasma field so that it’ll block high-frequency radiation like light.
Additionally, plasma can be shaped into thin plasma windows using electromagnetic fields and its heat can vaporize bullets. At incredibly hot levels (hotter than the surface of the sun), plasma becomes impermeable plasma, which is thick enough to outright block matter.
However, this theoretical shield also has its fair share of drawbacks. For starters, a shield that blocks visible light would mean that you can’t see through it. We could potentially get around this issue by using ultraviolet cameras to see through the shield, but there would still be problems. Specifically, low-frequency radiation like radio waves wouldn’t be able to pass through the shield, making communication difficult.
It would also require a massive amount of energy to generate the sustained electromagnetic field needed to contain and shape the plasma. The good news is that scientists may develop room temperature superconductors within the next 100 years, which will completely change the game. With this technology, we would be able to generate powerful magnetic fields using much smaller magnets and less energy. But, there’s still one last problem, and it’s a big one.
Plasma is a superhot gas, and electromagnetic fields don’t prevent heat from getting through. We’re talking the kind of superheated gas you find in stars like our sun, and plasma is currently used to weld metal together. So, if your protective dome is hot enough to vaporize bullets, it’s more than powerful enough to cook you to a crisp.
So, even though you could theoretically create the outer hull of a spaceship using only plasma, since it can separate air from vacuum, the interior of that vessel could be like walking on the sun.
Theoretical physicist Michio Kaku doesn’t believe that plasma windows may be enough to achieve the level of indestructibility that force fields are known for in science fiction. But layering with other types of materials might do the trick. He proposes that the first layer be made out of a plasma window to stop or vaporize most objects, a second layer comprised of a tight net of high-energy laser beams, followed by a thin sheet of incredibly resilient carbon nanotubes. Combined, these three layers would stop just about anything.
It would also require an immense amount of energy and wouldn’t have the same instant effect or versatility we see in sci-fi. That’s assuming the heat generated by the plasma and lasers don’t destroy everything that they’re supposed to protect.
Invincible force fields may be relegated to the imagination for now, but who knows what we might be capable of in the next century? Until then, we’ll just have to stick with old fashioned armor.