Creating Force Fields
A simple idea. Nearly impossible science.
Force fields are so commonplace in the radiant worlds of our science fiction that they are often left without explanation. Most stories don’t bother to touch on the science of the technology, nor do they have a definition for what exactly a force field is. The idea is simple enough: it’s a thin barrier made of energy or particles that is able to block solid matter — missiles, bullets, swords — and radiation. Force fields are primarily used as havens. They crop up over people and over towns, shielding them from the dangerous lasers or the heavy artillery heading their way. But one can imagine entirely new landscapes shaped by this technology. Not only would force fields have applications in war and space travel, but there could be entire cities constructed from them.
In physicist Michio Kaku’s Physics of the Impossible he mentions how force fields would replace everyday building materials like brick and steel. Instead, highways, bridges, and cities could materialize with the smallest effort. And in the strangest places. Because force fields can act as a barrier to the external world, it would be possible to have homes built in locations as unrelenting as the ocean depths. One imagines a futuristic city surrounded by the probing eyes of curious marine life. Beyond the glamorous space-green glow of the kelp forests, and beyond the tentacled reefs where prawn and polyps bathe in the sunlit salt waters, there could be the spectacle of human life brought down from the surface. Our towering buildings all surrounded by this thin, by this miraculous material we call a force field.
It is no exaggeration to say that the invention of this technology would revolutionize our lives. But as simple as the definition of a force field may be, its conception is not so straightforward.
Of the four forces of the universe — gravity, electromagnetism, and the strong and weak nuclear force — none seem to allow for the existence of a force field. In every case there is always some obstacle to its creation. Gravity is weak and works only on immense scales like those of stars and planets, electromagnetism cannot be contained to a small plane and can easily be neutralized, the nuclear forces are difficult to manipulate and act only on the scale of atoms. A fifth, as yet unseen force acting over a distance of inches or feet could allow for the creation of force fields, but so far there is no solid evidence that such a fifth force of nature exists.
So instead we turn to the states of matter. The most familiar are solids, liquids, and gasses. But these are not the most abundant state of matter in the universe. While not found in great quantities on Earth, plasma is the fourth state of matter and the most common throughout the cosmos. Over 99% of matter in the universe is plasma. In this state, electrons have been removed from their atoms, meaning that the plasma gas can now conduct electricity and is able to be influenced by magnetic fields. These magnetic fields can then shape the plasma into the thin planes of sci-fi force fields. If we create a plasma by heating up a gas like argon, the resulting gas will glow with a fantastical, electric blue color (or an ethereal lilac at lower voltages).
A sheet of plasma heated to high temperature and power will vaporize objects with which it comes into contact. And not only can it help stop bullets and everyday matter, but we already have evidence that plasma can stop radiation as well. Beginning at about 40 miles above the planet’s surface is the ionosphere. It is the last, wispy bit of Earth’s atmosphere before it gives way entirely to the vacuum of space. The gas here has been heated by the sun, becoming a plasma. Ions and free electrons run amok in the upper atmosphere, preventing radio waves from penetrating through. Radio waves are a kind of low-energy radiation. If future technology is able to produce denser sheets of plasma then they may be capable of blocking more high-energy forms of radiation such as the gamma and cosmic rays so harmful to an astronaut’s health. The problem with this, of course, is that to block high-energy radiation it would also need to block visible light, meaning that the view from within the plasma force fields would be an endless, eerie blankness.
Plasma on its own won’t give us the force fields of our science fiction dreams. Kaku suggests layering three separate technologies.
The first is the high-power plasma window which can vaporize incoming objects and block radiation. The second layer will consist of thousands of laser beams arranged in a tight lattice so that any objects not vaporized by the plasma screen will be vaporized at this point, by the laser beams. The final layer is an invisible but stable sheet of carbon nanotubes, a material like graphene that is only one atom thick — and thus transparent — but stronger than steel. The collective properties of these three layers should stop most incoming matter and radiation, providing a powerful defense for a city. Or for an intrepid team of astronauts on their journey to a new home.
The creation of a real life force field depends on advancement in various fields of technology, including that of photochromatics which would filter high-energy radiation (this is the same technology used in sunglasses which darken upon exposure to sunlight and help filter UVA and UVB light). Photochromatics would allow the force field to block incoming laser beams from the enemy side — whether the enemy side be another country or a race of hostile aliens come to raze the Earth.
Estimates for the development of this technology range from decades to centuries, a time which would coincide with our exploration of the Solar System’s nearby worlds. Magnetic force fields are being studied now for application on future space ships. However, many view them as impractical. To fully shield a ship from the most dangerous radiation would require a magnetic force field system of at least 9 tons. This is a tremendous amount of weight to carry considering how expensive flying any material into space can be.
When they do arrive, force fields will be a transformative technology. They push the boundaries of our science. So much more than just a dome under which to hide while under attack, they give us the material out of which to sculpt dream-like lives in deserts and in icelands. Their promise is to protect us from the destruction of war, and to ferry us safely through the destructive plasma wash of the cosmos.
