I was always a fan of the Protoss: super-advanced technology, powerful units, and those awesome plasma shields protecting everything from the lowliest probe to gigantic carriers. But I always wondered: could those force fields really work?
Well… Sort of.
It really depends on your definition of a force field and what you want to prevent from passing through. Electric and magnetic fields can exert forces on charged objects, so you could call those “force fields.” If you accept that definition, then there have actually been some NASA studies of how to use force fields on spacecraft and lunar bases.
One of the biggest problems facing human space exploration (aside from the politics) is that space is a dangerous place for humans. Even if we can launch people to Mars, there is a lot of radiation out there, both from the sun and from high-energy events out in the galaxy. That’s why two studies at NASA’s Institute for Advanced Concepts (which has, sadly, been canceled due to lack of funding) looked into deflecting the radiation with electromagnetic shields.
A lot of the radiation in space is in the form of charged particles: electrons, protons, and even larger atomic nuclei. If you remember your science classes, charged particles are attracted to objects with an opposite charge and repelled by objects with the same charge. So if you want to protect your lunar base, you just set up some strategically placed charged spheres, like so:
The other NIAC study focused on protecting the crew during long-duration missions. Even with advances in propulsion technology, it will still take months to get to Mars, and all the while the crew will be bombarded with radiation. Unless their ship is shielded! This concept would shield the spacecraft by using powerful magnetic fields to divert the solar wind plasma. “Plasma” in physics refers to a gas in which the atoms have been stripped of some (or all) of their electrons. That means that the plasma can be shaped by magnetic fields, creating a safe zone where the crew of the ship could stay protected.
You’re actually being protected from radiation by just such a shield right now! The Earth’s magnetic field diverts the solar wind and prevents it from hitting the surface, except at the poles. That’s why you only see auroras at the north and south pole: that is where all the solar wind plasma is being funneled down to hit the upper atmosphere. When the radiation hits the atmosphere, it excites the atoms and causes them to glow in the familiar colors of the aurora. The concept for the shielded ship would essentially create a miniature magnetosphere to protect the crew.
Ok, but let’s be honest: those shields are not nearly as cool as the protoss plasma shields. We want something that can stop bullets! We want to deflect hydralisk spines!
Well, I’m afraid nothing quite so awesome exists yet, but there is one bit of technology that is similar: plasma windows. These are narrow slabs of plasma confined by – you guessed it – magnetic fields. They actually have a lot in common with science fictional plasma shields! The hotter a plasma gets, the more viscous it gets, so plasma windows are actually able to act as a strong barrier between air and hard vacuum. Presumably, with enough energy you could create a plasma window capable of blocking more substantial regular matter. Right now plasma windows are tiny, but again, with a huge supply of energy, they could possibly be made larger. Interestingly, plasma windows do not block laser light or electron beams, so even if larger versions were made, they would not protect against weapons that used those forms of radiation.
Wrapping plasma windows all the way around something in a sphere would be very difficult, and projecting a shield onto a distant target, like the Terran science vessel’s “defensive matrix” capability is definitely not possible with today’s technology and understanding of physics.
So, unfortunately, plasma shields exactly like the ones that protect Protoss units are not realistic, but there are various force fields and plasma-shield-like technologies being developed. We may not be able to keep out bullets or zerglings, but some of the shields being developed block a much more realistic threat to human explorers: radiation.
Bamford, R., Gibson, K., Thornton, A., Bradford, J., Bingham, R., Gargate, L., Silva, L., Fonseca, R., Hapgood, M., Norberg, C., Todd, T., & Stamper, R. (2008). The interaction of a flowing plasma with a dipole magnetic field: measurements and modelling of a diamagnetic cavity relevant to spacecraft protection Plasma Physics and Controlled Fusion, 50 (12) DOI: 10.1088/0741-3335/50/12/124025