May 5, 2014 – In the scifi world shields protect spacecraft from light-based weapons like photon torpedoes, phasers and other directed-energy technologies. Spaceship battle cruisers use lasers the way our current military use artillery shells. Only recently have we seen directed-energy weaponry move from fiction to fact with the American navy deploying a test laser weapon system this coming summer.
Since yesterday was Star Wars day, “May the fourth be with you,” I thought it would be appropriate to look at the feasibility of building a shield to protect us from directed-energy weapons technology. It appears that such a defense may be possible.
In a paper entitled, “Shields Up! The Physics of Star Wars,” written by three fourth-year physics students at University of Leicester, and published in the Journal of Physics Special Topics, they describe the feasibility of creating a magnetic shield capable of deflecting photon torpedoes and all the other light-based weapons that populate the science fiction of Star Wars and Star Trek.
The model for creating a shield comes from two natural features of our planet, the ionosphere, lying 50 to 80 kilometers (30 to 50 miles) above the Earth’s surface, and the magnetosphere, extending tens of thousands of kilometers into near-Earth space. These two regions protect us from extraterrestrial radiation, the charged particles that rain down on our planet from space every day. It is our ionosphere that makes radio communications and radar function by reflecting the beams from both back to Earth. It also shields us from ultraviolet light and skin cancer.
The university students in their peer-reviewed paper propose that a plasma shield could work similarly reflecting light-based and directed-energy weapons away from a properly equipped spaceship. Unfortunately to build a shield today would require a massive magnetic array and significant power source, clearly beyond our current capability.
One other issue pointed out by the student authors of this paper, those on board a shielded ship would be flying blind. In deflecting light-based and directed-energy weapons, all other visible light would be blocked.
On a practical level, this theoretical shield could prove to be an effective protection for ground-based applications including protecting us from radiation emitted by nuclear power plants. And for those planning to make Mars a future home, such a shield would prove highly useful in protecting any surface habitations from the ill effects of cosmic rays.