ARE FORCE FIELDS THE MUGGLE VERSION OF SHIELD CHARMS?

Picture this: Hogwarts castle under siege from all manner of death eaters and dark creatures. In an external courtyard of the castle, and under cover of darkness, Professor McGonagall declares, “Hogwarts is threatened! Man the boundaries and protect us! Do your duty to our school!” Countless castle statues and gargoyles thunder past, heading toward the viaduct and the position of the invading dark forces, all to McGonagall’s evident delight, “I’ve always wanted to use that spell.”

A few yards away, Professor Flitwick waved his wand aloft and the summoning began, “Protego Maxima. Fianto Duri. Repello Inimicum”. As other witches and wizards join with Flitwick, we see a momentary disturbance in the dark skies above the castle. Together they conjure a magical shield, expanding ever outward, bubbling and blooming over the castle’s estate, as far below the statues and gargoyles marched along the viaduct and took their posts along the perimeter.

Flitwick had conjured up a shield charm on the castle. Protego Maxima was a strong shield charm which, when cast in combination with Fianto Duri and Repello Inimicum raised an almost unbreakable magical wall of defense. The charms created magical barriers to deter and deflect physical objects and spells, which could work to protect a person or a locale. When done well, conjurations would often rebound directly off a shield charm, back towards the caster or ricocheting off in random space as soon as they hit the shield. Shield charms seem so easily summoned in magic. But could muggle technology conjure up something similar?

Fantasy Force Fields

All matter is made of atoms. Atoms are bound by forces. Take away atoms. Leave the forces behind. That’s a force field. Well, at least that’s a force field in science fantasy. In physics, a force field can have a different meaning, but for fantasy it’s usually an invisible protective sphere, or wall of force. It’s a concept we all know and love. It’s what happens when aliens, rogue asteroids, or killer wizards are winging your way. Just slap up a force field and pour a cocktail. Job done.

The first force field found its way into fantasy in America in the 1930’s and 40’s. In E.E. ‘Doc’ Smith’s Skylark and Lensman books, when force fields were under attack they typically glowed red and orange and then all the way through the spectrum until they got to violet and black, at which point they broke down. Smith’s fields were a forerunner of the modern deflector on the S.S. Enterprise in Star Trek.

In modern movies, force fields are accepted without question. Take the 1996 movie, Independence Day, for example. Disabling the protective force fields of the spaceships of the invading forces is a key plot point. It renders the hostile aliens vulnerable to nuclear attack. And yet the force field is presented seemingly without need of explanation. This situation has become so endemic in fantasy that stories commonly have force fields surrounding entire solar systems!

The truth is more problematic. There is no known force capable of repelling all objects and energies. But muggles are working on it. Scientists at NASA’s Kennedy Space Center and the NASA Institute for Advanced Concepts are researching the possibility of electric shields, for use on Earth, or even bases on the moon, for example. Most of the deadly radiation in space is made up of electrically charged particles. So why not use a powerful electric field that has the same charge as the incoming radiation, thus deflecting the radiation away?

Real Life Force Fields

Recently, scientists found an invisible shield, around 7,200 miles (11,600 km) above Earth. And this shield certainly helps repel ‘dark’ forces. The shield blocks ‘killer electrons’, which would otherwise be free to bombard our little planet. Now these ‘killer electrons’ can whizz about the globe at near-light speed. They spook astronauts, fry satellites, and wreck space systems. And, if they hit Earth on a massive scale, they could take out power grids, radically alter our climate, and send cancer rates spiking to an all-time high.

The nature of the shield itself remains a mystery. Though scientists know of its existence through its effects, they are puzzled about its formation and function. But there is little doubt this real-life shield is somewhat like the shields created by shield charms at Hogwarts, and force fields on Star Trek. The main difference is that rather than repelling death eaters or aliens, this invisible shield blocks high-energy electrons.

7,200 miles above the Earth puts this invisible shield in the Van Allen radiation belts. The Van Allen belts are two doughnut-shaped rings that sit in the Earth’s atmosphere. They’re replete with high-energy protons and electrons, and held in sway by the Earth’s magnetic field. They ebb and flow, and shrink and swell, in response to inbound energy surges from our sun. The Van Allen belts were found in 1958, and are composed of an inner and outer belt extending up to 25,000 miles (40,000km) above the planet’s surface.

But recently a third, transient ‘storage ring’ was found, hidden in the belts. This mystery third ring was discovered by the twin Van Allen Probes, launched in 2012. The ring seems to wax and wane with the intensity of space weather. But it blocks the ultrafast electrons from breaching its barrier, and probing down deeper towards the Earth. Science teams are a little puzzled by the phenomenon, but hope to learn from nature’s example, which may help us understand how to make artificial force fields.

The third ring is like a glass wall in space, akin to that bubble in the dark skies above Hogwarts. At first, scientists were worried that the highly-charged electrons, which are looping about the globe at speeds greater than 100,000 miles per second, would veer down into the upper atmosphere. But the ‘glass wall’ stops the electrons before they get that far. If the science teams can work out how the glass wall operates, they may be able to mimic its capabilities and make a man-made barrier that does the same.

Scientists have been working out how such a glass wall might be created and sustained in space. One theory is that the wall is made by the Earth’s magnetic field lines. These magnetic lines capture and control charged particles, such as protons and electrons. The particles are made to prance between the planet’s poles like angry birds on a wire. Another theory is that radio signals from human activity on Earth could be scattering the charged electrons at the barrier, preventing their downward motion. But neither theory holds scientific water. At the moment, the science teams simply don’t know how the slow and steady motion of these particles can suddenly conspire to create such a sharp and stubborn boundary at this ‘glass wall’ in space.

And yet a third theory is more interesting still. It suggests that a giant cloud of cold, electrically charged gas, beginning about 600 miles (960km) above the Earth, is scattering the electrons at the boundary. The name of this giant cloud? The plasma sphere! Now, that does sound like a force field.