Lightsabers

Lightsabers are quintessential to the Star Wars franchise, serving as more than just flashy weapons; they also symbolize the emotional struggles of characters. Imagine the iconic confrontation between Luke and Darth Vader in The Empire Strikes Back without the dramatic lightsaber duel that precedes it. But does the underlying science hold water?

According to the expanded lore, lightsabers derive their power and color from kyber crystals found in various locations throughout the galaxy, such as Jedha from Rogue One. While these crystals might not exist in our world, we can still question the practicality of different lightsaber designs and colors.

Typically, a lightsaber measures around 3 feet in length. Whether creating a beam of that size is feasible depends on whether it's composed of light or plasma.

Light beams are challenging to contain, as photons are notoriously difficult to redirect or halt mid-flight. A simple solution might involve using mirrors to reflect light, but this contradicts the films' portrayal, where inactive lightsabers are only as long as their hilts. The iconic sound of a lightsaber activating could hypothetically stem from the sound of light being released, yet several complications arise.

For instance, the beam's visibility presents a conundrum. If you’ve ever pointed a laser at your skin, you know it’s harmless. To inflict damage, a laser's power would need to increase substantially—by about a factor of a thousand—accompanied by a significant cooling system. Moreover, a beam of light, regardless of its intensity, cannot deflect plasma projectiles. Essentially, wielding a miniature sun would necessitate extreme sun protection.

On the other hand, if we consider a lightsaber as a plasma weapon, we enter a different realm of challenges. A well-crafted electromagnetic field could theoretically confine plasma to a 3-foot length by following an elliptical path. Plasma can cauterize wounds and melt metal, aligning with their depiction in the films, but issues arise when imagining two plasma beams colliding. Rather than clashing, they would attract each other, making it improbable to deflect a blaster shot while explaining the absorption of force lightning.

The color variations in plasma relate directly to their temperature. A red lightsaber would signify lower energy compared to a green one, assuming both are made from the same materials. Generating these colors in plasma is complex, and while we know a great deal about hydrogen-based plasma colors, the results of cobalt plasma remain an open question.

Due to the extreme temperatures of plasma, being near one would undoubtedly result in severe burns. The sun's distance requires us to wear sunscreen to shield against its rays, yet a handheld plasma weapon would necessitate protection equivalent to SPF 10,000.

Alternative explanations for lightsaber functionality could either involve fantasy elements (like kyber crystals) or extraordinary engineering that transcends mere light or plasma.

Blasters

Blasters are prevalent throughout the Star Wars saga, utilized by everyone from the Galactic Empire to bounty hunters. While Jedi might deem them "clumsy," they are essential tools for many characters. A particularly infamous scene is the "Han shot first" moment in Episode IV, where the original portrayal had Han shooting Greedo without a need for dodging. The subsequent edits imply that even at close range, blaster shots can be evaded, lending credence to the notion of their erratic nature.

Some portray blasters as laser weapons, while others categorize them as plasma weapons. In the plasma scenario, tibanna gas—mined in locations like Cloud City—is compressed and energized, launching a bolt toward a target. This raises questions about the temperature at which tibanna gas transforms into plasma, estimated to be around 360,000 degrees Fahrenheit. Contact with such a high-temperature gas would likely vaporize any body part it touches.

However, a plasma-based blaster introduces complications. The charged particles that comprise plasma are susceptible to electromagnetic forces. If a plasma bolt travels at around 73 miles per hour, a magnetic field a million times weaker than Earth's would be enough to alter its path significantly. This may clarify the apparent inaccuracy of stormtrooper fire. If a stormtrooper were to fire on Earth, stray magnetic fields could lead the bolt to veer back and hit the weapon itself.

Conversely, if blasters are indeed laser guns, their accuracy would be higher since light is far more difficult to redirect. While laser pointers are typically harmless, a class 4 laser—which could cause burns and ignite materials—would align more closely with blaster functionality. Class 4 lasers operate above 500 milliwatts, and prolonged contact could result in severe injuries, consistent with Leia's injuries on Endor.

Ultimately, neither explanation completely aligns with the cinematic portrayal. If one theory stands out, it is the plasma explanation, suggesting either a lack of magnetic fields in the film or advanced technology to slow down light.

Electrostaff

The electrostaff, a weapon wielded mainly by General Grievous's guards, consists of a 6-foot staff with electrical discharges at both ends. Its effectiveness against Jedi like Obi-Wan and Anakin is showcased in Episode III. But how viable is such a weapon? Would it withstand a lightsaber's blade, and could it break a spaceship window if thrown forcefully enough?

Creating sustained electrical discharges over a foot requires a significant voltage, typically around a million volts. The design could be achievable by employing a capacitor mechanism—metal rings charged with high voltage that ionize air at a sufficient distance. However, practical usage poses challenges; if the staff ends are too close to metal surfaces, they would discharge prematurely.

Could an electrostaff block a lightsaber or shatter a spaceship window? The short answer is no and yes, respectively. While it’s theoretically possible for an electrostaff to disperse a lightsaber beam, it wouldn’t operate as depicted in the films. Breaking a window would require immense force, but a well-thrown staff could potentially accomplish that.

Ion Cannons

In The Empire Strikes Back, the rebels use ion cannons to protect their evacuation. These weapons successfully disable a Star Destroyer with a few shots. While the specific destructive capability of ion cannons is only depicted once, they appear to send a powerful electrical surge through enemy ships, akin to an electromagnetic pulse.

Vaporizing asteroids, as seen in the film, necessitates heating them to their melting and evaporating points. For iron or silicate rock asteroids, this would require approximately 10¹⁴ joules of energy—roughly ten times the energy released in the Hiroshima atomic bomb. Such energy demands are daunting but not impossible.

Firing high-powered weapons like ion cannons presents additional challenges. A beam of ions can undergo blooming, causing it to spread out and lose effectiveness. Thermal blooming is exacerbated in snowy conditions, such as those on Hoth. In scenarios involving magnetic fields, ions could deviate from their trajectory, further complicating the aim of these weapons.

Designing an effective ion weapon would likely necessitate a spherical or disk shape, allowing ions to move in circular paths for optimal heating before being fired. This design could elucidate the delay between shots, as sufficient time is required to accelerate the ions to lethal speeds.

In conclusion, while the technology depicted in Star Wars is fictional, examining the underlying physics can yield fascinating insights and discussions about feasibility.

Explore how blasters function within the Star Wars universe and the science behind their operation.

Investigate whether the first real Star Wars blaster is a possibility and the science that could make it happen.

Patrick Johnson is a member of the teaching faculty at Georgetown University, primarily teaching introductory physics.

From Physics of Star Wars by Patrick Johnson, Ph.D. Copyright © 2017 by Simon & Schuster, Inc. Used with permission of the publisher. All rights reserved.